@article{
 title = {Complex Defect Chemistry of Hydrothermally-synthesized Nb-substituted β′-LiVOPO 4},
 type = {article},
 year = {2023},
 pages = {121},
 websites = {http://pubs.rsc.org/en/Content/ArticleLanding/2023/TA/D3TA01152F},
 id = {901dee11-5780-3f8c-86a5-3a5a681a710f},
 created = {2023-05-02T01:58:34.938Z},
 file_attached = {true},
 profile_id = {acecf9ac-a9eb-39c3-b1a6-bdadc9df448a},
 last_modified = {2023-05-11T03:09:27.890Z},
 read = {true},
 starred = {false},
 authored = {true},
 confirmed = {true},
 hidden = {false},
 private_publication = {false},
 abstract = {Lithium vanadyl phosphate (LiVOPO4) is a next-generation multielectron battery cathode that can intercalate up to two Li-ions per V-ion through the redox couples of V 4+ /V 3+ and V 5+ /V 4+ . However, its rate...},
 bibtype = {article},
 author = {Lee, Krystal and Zhou, Hui and Zuba, Mateusz J and Kaplan, Carol M and Zong, Yanxu and Qiao, Linna and Zhou, Guangwen and Chernova, Natasha A. and Liu, Hao and Whittingham, Stanley},
 doi = {10.1039/D3TA01152F},
 journal = {Journal of Materials Chemistry A},
 number = {207890}
}

Lithium vanadyl phosphate (LiVOPO4) is a next-generation multielectron battery cathode that can intercalate up to two Li-ions per V-ion through the redox couples of V 4+ /V 3+ and V 5+ /V 4+ . However, its rate...

@article{
 title = {Oxygen Loss in Layered Oxide Cathodes for Li-Ion Batteries: Mechanisms, Effects, and Mitigation},
 type = {article},
 year = {2022},
 pages = {5641-5681},
 volume = {122},
 websites = {https://pubs.acs.org/doi/10.1021/acs.chemrev.1c00327},
 month = {3},
 day = {23},
 id = {ca348b0a-cc3d-3c6d-885a-da7c32f1966f},
 created = {2022-02-03T14:23:14.026Z},
 file_attached = {true},
 profile_id = {acecf9ac-a9eb-39c3-b1a6-bdadc9df448a},
 last_modified = {2022-03-31T17:16:25.199Z},
 read = {true},
 starred = {false},
 authored = {true},
 confirmed = {true},
 hidden = {false},
 private_publication = {false},
 abstract = {Layered lithium transition metal oxides derived from LiMO2 (M = Co, Ni, Mn, etc.) have been widely adopted as the cathodes of Li-ion batteries for portable electronics, electric vehicles, and energ...},
 bibtype = {article},
 author = {Zhang, Hanlei and Liu, Hao and Piper, Louis F. J. and Whittingham, M. Stanley and Zhou, Guangwen},
 doi = {10.1021/acs.chemrev.1c00327},
 journal = {Chemical Reviews},
 number = {6}
}

Layered lithium transition metal oxides derived from LiMO2 (M = Co, Ni, Mn, etc.) have been widely adopted as the cathodes of Li-ion batteries for portable electronics, electric vehicles, and energ...

@article{
 title = {Surface Reduction Stabilizes the Single-Crystalline Ni-Rich Layered Cathode for Li-Ion Batteries},
 type = {article},
 year = {2022},
 pages = {38795-38806},
 volume = {14},
 websites = {https://doi.org/10.26434/chemrxiv-2022-fplt1,https://pubs.acs.org/doi/10.1021/acsami.2c09937},
 month = {8},
 day = {31},
 id = {dab1c803-3b7a-3201-9233-3c5961aa1350},
 created = {2022-06-17T02:22:37.084Z},
 file_attached = {true},
 profile_id = {acecf9ac-a9eb-39c3-b1a6-bdadc9df448a},
 last_modified = {2022-10-06T00:23:39.028Z},
 read = {true},
 starred = {false},
 authored = {true},
 confirmed = {true},
 hidden = {false},
 private_publication = {false},
 bibtype = {article},
 author = {Fan, Qinglu and Zuba, Mateusz Jan and Zong, Yanxu and Menon, Ashok S. and Pacileo, Anthony T. and Piper, Louis F.J. and Zhou, Guangwen and Liu, Hao},
 doi = {10.1021/acsami.2c09937},
 journal = {ACS Applied Materials & Interfaces},
 number = {34}
}

@article{
 title = {Reaction Mechanism of Na-Ion Deintercalation in Na 2 CoSiO 4},
 type = {article},
 year = {2022},
 pages = {16983-16992},
 volume = {126},
 websites = {https://pubs.acs.org/doi/10.1021/acs.jpcc.2c05314},
 month = {10},
 day = {13},
 id = {861e4975-b182-32f7-85d4-8c7746ecd7da},
 created = {2022-11-04T19:16:45.810Z},
 file_attached = {true},
 profile_id = {acecf9ac-a9eb-39c3-b1a6-bdadc9df448a},
 last_modified = {2022-11-04T19:18:27.828Z},
 read = {true},
 starred = {false},
 authored = {true},
 confirmed = {true},
 hidden = {false},
 private_publication = {false},
 abstract = {Sodium transition metal silicates are potential candidate electrode materials to enable two-electron redox per transition metal ion center. Yet, the electrochemical reaction mechanism remains elusive despite the widely reported electrochemical activity for this class of materials as intercalation cathodes for Na-ion batteries. Adopting monoclinic Na2CoSiO4 as a model compound, we used high-resolution synchrotron X-ray diffraction (XRD) and X-ray pair distribution function (PDF) analysis to elucidate the structure of the partially desodiated Na2-xCoSiO4 phases for the Co3+/Co2+ redox couple. The appearance of satellite reflections in the intermediate Na1.5CoSiO4 and NaCoSiO4 phases manifests the formation of modulated structures, which are induced by Na+/vacancy and Co2+/Co3+ charge orderings. Accounting for these structural orderings is important to understand the function and performance of sodium transition metal silicate electrodes.},
 bibtype = {article},
 author = {Wang, Jiwei and Hoteling, Grayson and Shepard, Robert and Wahila, Matthew and Wang, Fei and Smeu, Manuel and Liu, Hao},
 doi = {10.1021/acs.jpcc.2c05314},
 journal = {The Journal of Physical Chemistry C},
 number = {40}
}

Sodium transition metal silicates are potential candidate electrode materials to enable two-electron redox per transition metal ion center. Yet, the electrochemical reaction mechanism remains elusive despite the widely reported electrochemical activity for this class of materials as intercalation cathodes for Na-ion batteries. Adopting monoclinic Na2CoSiO4 as a model compound, we used high-resolution synchrotron X-ray diffraction (XRD) and X-ray pair distribution function (PDF) analysis to elucidate the structure of the partially desodiated Na2-xCoSiO4 phases for the Co3+/Co2+ redox couple. The appearance of satellite reflections in the intermediate Na1.5CoSiO4 and NaCoSiO4 phases manifests the formation of modulated structures, which are induced by Na+/vacancy and Co2+/Co3+ charge orderings. Accounting for these structural orderings is important to understand the function and performance of sodium transition metal silicate electrodes.

@article{
 title = {Structure, Composition, and Electrochemistry of Chromium-Substituted ε-LiVOPO 4},
 type = {article},
 year = {2021},
 keywords = {disordered structure,elemental substitution,high-energy density cathode,hydrothermal synthesis,lithium-ion batteries,livopo 4,multielectron redox},
 pages = {1421-1430},
 volume = {4},
 websites = {https://pubs.acs.org/doi/10.1021/acsaem.0c02634},
 month = {2},
 day = {22},
 id = {5b4e5ed0-a058-3641-9d7a-89ec32e63614},
 created = {2021-03-19T19:25:47.407Z},
 file_attached = {true},
 profile_id = {acecf9ac-a9eb-39c3-b1a6-bdadc9df448a},
 last_modified = {2022-05-10T03:00:49.021Z},
 read = {true},
 starred = {false},
 authored = {true},
 confirmed = {true},
 hidden = {false},
 private_publication = {false},
 abstract = {Lithium vanadyl phosphate (LiVOPO4) is an attractive cathode material for next-generation lithium-ion batteries, having the ability to reversibly intercalate two Li ions per transition metal redox center to reach a theoretical capacity of 305 mAh g-1. This material has a high energy density with two voltage plateaus of 2 and 4 V. However, reduced capacity retention at faster rates and sluggish kinetics in the high-voltage region leaves much room for improvement. Cr substitution was implemented to mitigate these limitations and enhance the electrochemical performance of ε-LiVOPO4. By various characterization techniques, we have established the composition of the hydrothermally synthesized Cr-substituted samples to be LixHyCrzV1-zOPO4 solid solution (0.80 ≤ x ≦ 0.85, 0.25 ≦ y ≦ 0.60, and z ≦ 0.05). All Cr-substituted samples demonstrated higher coulombic efficiency and superior cycling stability for over 40 cycles at C/15. Electrochemical tests show Cr substitution enhances the Li-ion diffusion in the high-voltage regime and the reaction reversibility of ε-LiVOPO4.},
 bibtype = {article},
 author = {Lee, Krystal and Siu, Carrie and Hidalgo, Marc F. V. and Rana, Jatinkumar and Zuba, Mateusz and Chung, Youngmin and Omenya, Fredrick and Piper, Louis F. J. and Liu, Hao and Chernova, Natasha A. and Whittingham, M. Stanley},
 doi = {10.1021/acsaem.0c02634},
 journal = {ACS Applied Energy Materials},
 number = {2}
}

Lithium vanadyl phosphate (LiVOPO4) is an attractive cathode material for next-generation lithium-ion batteries, having the ability to reversibly intercalate two Li ions per transition metal redox center to reach a theoretical capacity of 305 mAh g-1. This material has a high energy density with two voltage plateaus of 2 and 4 V. However, reduced capacity retention at faster rates and sluggish kinetics in the high-voltage region leaves much room for improvement. Cr substitution was implemented to mitigate these limitations and enhance the electrochemical performance of ε-LiVOPO4. By various characterization techniques, we have established the composition of the hydrothermally synthesized Cr-substituted samples to be LixHyCrzV1-zOPO4 solid solution (0.80 ≤ x ≦ 0.85, 0.25 ≦ y ≦ 0.60, and z ≦ 0.05). All Cr-substituted samples demonstrated higher coulombic efficiency and superior cycling stability for over 40 cycles at C/15. Electrochemical tests show Cr substitution enhances the Li-ion diffusion in the high-voltage regime and the reaction reversibility of ε-LiVOPO4.

@article{
 title = {Al Substitution for Mn during Co-Precipitation Boosts the Electrochemical Performance of LiNi 0.8 Mn 0.1 Co 0.1 O 2},
 type = {article},
 year = {2021},
 pages = {050532},
 volume = {168},
 websites = {https://iopscience.iop.org/article/10.1149/1945-7111/ac0020},
 month = {5},
 publisher = {IOP Publishing},
 day = {1},
 id = {cf7c212e-7d4f-3d52-8747-5e42ccfd7301},
 created = {2021-05-21T13:55:06.436Z},
 file_attached = {true},
 profile_id = {acecf9ac-a9eb-39c3-b1a6-bdadc9df448a},
 last_modified = {2021-05-21T13:55:11.729Z},
 read = {true},
 starred = {false},
 authored = {true},
 confirmed = {true},
 hidden = {false},
 private_publication = {false},
 bibtype = {article},
 author = {Pei, Ben and Zhou, Hui and Goel, Anshika and Zuba, Mateusz and Liu, Hao and Xin, Fengxia and Whittingham, M. Stanley},
 doi = {10.1149/1945-7111/ac0020},
 journal = {Journal of The Electrochemical Society},
 number = {5}
}

@article{
 title = {Best practices for operando depth-resolving battery experiments},
 type = {article},
 year = {2020},
 keywords = {batteries,depth profiling,operando,pair distribution function analysis},
 pages = {133-139},
 volume = {53},
 websites = {http://scripts.iucr.org/cgi-bin/paper?S1600576719016315},
 month = {2},
 day = {1},
 id = {da3a21b1-54b5-3de5-87e0-a57a5c6b9174},
 created = {2020-03-30T20:06:32.997Z},
 file_attached = {true},
 profile_id = {acecf9ac-a9eb-39c3-b1a6-bdadc9df448a},
 last_modified = {2022-04-15T13:11:48.081Z},
 read = {true},
 starred = {false},
 authored = {true},
 confirmed = {true},
 hidden = {false},
 private_publication = {false},
 abstract = {Operando studies that probe how electrochemical reactions propagate through a battery provide valuable feedback for optimizing the electrode architecture and for mitigating reaction heterogeneity. Transmission-geometry depth-profiling measurements carried out with the beam directed parallel to the battery layers – in a radial geometry – can provide quantitative structural insights that resolve depth-dependent reaction heterogeneity which are not accessible from conventional transmission measurements that traverse all battery layers. However, these spatially resolved measurements are susceptible to aberrations that do not affect conventional perpendicular-beam studies. Key practical considerations that can impact the interpretation of synchrotron depth-profiling studies, which are related to the signal-to-noise ratio, cell alignment and lateral heterogeneity, are described. Strategies to enable accurate quantification of state of charge during rapid depth-profiling studies are presented.},
 bibtype = {article},
 author = {Liu, Hao and Li, Zhuo and Grenier, Antonin and Kamm, Gabrielle E. and Yin, Liang and Mattei, Gerard S. and Cosby, Monty R. and Khalifah, Peter G. and Chupas, Peter J. and Chapman, Karena W.},
 doi = {10.1107/S1600576719016315},
 journal = {Journal of Applied Crystallography},
 number = {1}
}

Operando studies that probe how electrochemical reactions propagate through a battery provide valuable feedback for optimizing the electrode architecture and for mitigating reaction heterogeneity. Transmission-geometry depth-profiling measurements carried out with the beam directed parallel to the battery layers – in a radial geometry – can provide quantitative structural insights that resolve depth-dependent reaction heterogeneity which are not accessible from conventional transmission measurements that traverse all battery layers. However, these spatially resolved measurements are susceptible to aberrations that do not affect conventional perpendicular-beam studies. Key practical considerations that can impact the interpretation of synchrotron depth-profiling studies, which are related to the signal-to-noise ratio, cell alignment and lateral heterogeneity, are described. Strategies to enable accurate quantification of state of charge during rapid depth-profiling studies are presented.

@article{
 title = {Intrinsic Kinetic Limitations in Substituted Lithium-Layered Transition-Metal Oxide Electrodes},
 type = {article},
 year = {2020},
 pages = {7001-7011},
 volume = {142},
 websites = {https://pubs.acs.org/doi/abs/10.1021/jacs.9b13551},
 month = {4},
 day = {15},
 id = {5f321dfa-1667-376b-8d1a-ec306cc4991d},
 created = {2020-05-13T14:36:21.147Z},
 file_attached = {true},
 profile_id = {acecf9ac-a9eb-39c3-b1a6-bdadc9df448a},
 last_modified = {2020-06-19T19:47:56.136Z},
 read = {true},
 starred = {false},
 authored = {true},
 confirmed = {true},
 hidden = {false},
 private_publication = {false},
 abstract = {Substituted Li layered transition metal oxide (LTMO) electrodes such as LixNiyMnzCo1-y-zO2 (NMC) and LixNiyCo1-y-zAlzO2 (NCA) show reduced first cycle Coulombic efficiency (90-87 % in standard cycl...},
 bibtype = {article},
 author = {Grenier, Antonin and Reeves, Philip J. and Liu, Hao and Seymour, Ieuan D. and Märker, Katharina and Wiaderek, Kamila M. and Chupas, Peter J. and Grey, Clare P. and Chapman, Karena W.},
 doi = {10.1021/jacs.9b13551},
 journal = {Journal of the American Chemical Society},
 number = {15}
}

Substituted Li layered transition metal oxide (LTMO) electrodes such as LixNiyMnzCo1-y-zO2 (NMC) and LixNiyCo1-y-zAlzO2 (NCA) show reduced first cycle Coulombic efficiency (90-87 % in standard cycl...

@article{
 title = {Quantifying Reaction and Rate Heterogeneity in Battery Electrodes in 3D through Operando X-ray Diffraction Computed Tomography},
 type = {article},
 year = {2019},
 keywords = {computed tomography,li-ion batteries,lifepo 4,operando,reaction heterogeneity,thick electrode,x-ray di ff raction},
 pages = {18386-18394},
 volume = {11},
 websites = {http://pubs.acs.org/doi/10.1021/acsami.9b02173,https://pubs.acs.org/doi/10.1021/acsami.9b02173},
 month = {5},
 day = {22},
 id = {8ae1833f-9352-3bfc-9297-bdc54c4e6d36},
 created = {2019-05-22T18:44:36.140Z},
 file_attached = {true},
 profile_id = {acecf9ac-a9eb-39c3-b1a6-bdadc9df448a},
 last_modified = {2020-06-19T19:47:56.981Z},
 read = {true},
 starred = {false},
 authored = {true},
 confirmed = {true},
 hidden = {false},
 private_publication = {false},
 bibtype = {article},
 author = {Liu, Hao and Kazemiabnavi, Saeed and Grenier, Antonin and Vaughan, Gavin and Di Michiel, Marco and Polzin, Bryant J. and Thornton, Katsuyo and Chapman, Karena W. and Chupas, Peter J.},
 doi = {10.1021/acsami.9b02173},
 journal = {ACS Applied Materials & Interfaces},
 number = {20}
}

@article{
 title = {Revisiting the charge compensation mechanisms in LiNi<sub>0.8</sub>Co<sub>0.2−y</sub>Al<sub>y</sub>O<sub>2</sub> systems},
 type = {article},
 year = {2019},
 pages = {2112-2123},
 volume = {6},
 websites = {http://xlink.rsc.org/?DOI=C9MH00765B},
 id = {9bd3242d-9bf1-3c2e-9c80-5b38ed3f4108},
 created = {2019-11-05T01:50:47.855Z},
 file_attached = {true},
 profile_id = {acecf9ac-a9eb-39c3-b1a6-bdadc9df448a},
 last_modified = {2020-03-30T20:06:37.900Z},
 read = {true},
 starred = {false},
 authored = {true},
 confirmed = {true},
 hidden = {false},
 private_publication = {false},
 abstract = {The emergence of oxidized oxygen RIXS features at high voltages for Ni-rich layered oxide cathodes.},
 bibtype = {article},
 author = {Lebens-Higgins, Zachary W. and Faenza, Nicholas V. and Radin, Maxwell D. and Liu, Hao and Sallis, Shawn and Rana, Jatinkumar and Vinckeviciute, Julija and Reeves, Philip J. and Zuba, Mateusz J. and Badway, Fadwa and Pereira, Nathalie and Chapman, Karena W. and Lee, Tien-Lin and Wu, Tianpin and Grey, Clare P. and Melot, Brent C. and Van Der Ven, Anton and Amatucci, Glenn G. and Yang, Wanli and Piper, Louis F. J.},
 doi = {10.1039/C9MH00765B},
 journal = {Materials Horizons},
 number = {10}
}

The emergence of oxidized oxygen RIXS features at high voltages for Ni-rich layered oxide cathodes.

@article{
 title = {Reactivity-Guided Interface Design in Na Metal Solid-State Batteries},
 type = {article},
 year = {2019},
 keywords = {coating,computation,first-principles,high-energy density,hydrate,interfacial stability,metal anode,solid electrolyte,solid-state batteries,synchrotron X-ray diffraction},
 pages = {1-14},
 volume = {0},
 websites = {https://doi.org/10.1016/j.joule.2018.12.019,https://www.cell.com/joule/fulltext/S2542-4351(18)30625-1,https://linkinghub.elsevier.com/retrieve/pii/S2542435118306251},
 month = {1},
 publisher = {Elsevier Inc.},
 id = {3e51d7bc-554e-361a-bf16-864d784c58e1},
 created = {2020-01-29T03:23:53.262Z},
 file_attached = {true},
 profile_id = {acecf9ac-a9eb-39c3-b1a6-bdadc9df448a},
 last_modified = {2020-01-29T03:24:07.595Z},
 read = {true},
 starred = {false},
 authored = {true},
 confirmed = {true},
 hidden = {false},
 private_publication = {false},
 abstract = {Summary Solid-state batteries provide substantially increased safety and improved energy density when energy-dense alkali metal anodes are applied. However, most solid-state electrolytes react with alkali metals, causing a continuous increase of the cell impedance. Here, we employ a reactivity-driven strategy to improve the interfacial stability between a Na3SbS4 solid-state electrolyte and sodium metal. First-principles calculations identify a protective hydrate coating for Na3SbS4 that leads to the generation of passivating decomposition products upon contact of the electrolyte with sodium metal. The formation of this protective coating, a newly discovered hydrated phase, is achieved experimentally through exposure of Na3SbS4 to air. The buried interface is characterized using post-operando synchrotron X-ray depth profiling, providing spatially resolved evidence of the multilayered phase distribution in the Na metal symmetric cell consistent with theoretical predictions. We identify hydrates as promising for improving the metal/electrolyte interfacial stability in solid-state batteries and suggest a general strategy of interface design for this purpose.},
 bibtype = {article},
 author = {Tian, Yaosen and Sun, Yingzhi and Hannah, Daniel C. and Xiao, Yihan and Liu, Hao and Chapman, Karena W. and Bo, Shou-Hang Hang and Ceder, Gerbrand},
 doi = {10.1016/j.joule.2018.12.019},
 journal = {Joule},
 number = {0}
}

Summary Solid-state batteries provide substantially increased safety and improved energy density when energy-dense alkali metal anodes are applied. However, most solid-state electrolytes react with alkali metals, causing a continuous increase of the cell impedance. Here, we employ a reactivity-driven strategy to improve the interfacial stability between a Na3SbS4 solid-state electrolyte and sodium metal. First-principles calculations identify a protective hydrate coating for Na3SbS4 that leads to the generation of passivating decomposition products upon contact of the electrolyte with sodium metal. The formation of this protective coating, a newly discovered hydrated phase, is achieved experimentally through exposure of Na3SbS4 to air. The buried interface is characterized using post-operando synchrotron X-ray depth profiling, providing spatially resolved evidence of the multilayered phase distribution in the Na metal symmetric cell consistent with theoretical predictions. We identify hydrates as promising for improving the metal/electrolyte interfacial stability in solid-state batteries and suggest a general strategy of interface design for this purpose.

@article{
 title = {Localized concentration reversal of lithium during intercalation into nanoparticles},
 type = {article},
 year = {2018},
 pages = {eaao2608},
 volume = {4},
 websites = {http://advances.sciencemag.org/lookup/doi/10.1126/sciadv.aao2608},
 id = {ecbc9ff9-f633-3e51-a2a6-680eb06d408e},
 created = {2018-01-17T14:57:42.695Z},
 file_attached = {true},
 profile_id = {acecf9ac-a9eb-39c3-b1a6-bdadc9df448a},
 last_modified = {2018-09-18T15:39:18.813Z},
 read = {false},
 starred = {false},
 authored = {true},
 confirmed = {true},
 hidden = {false},
 folder_uuids = {b7fc39ea-b907-41ad-867d-d41108aaba7d},
 private_publication = {false},
 abstract = {Nanoparticulate electrodes, such as Li x FePO4, have unique advantages over their microparticulate counterparts for the applications in Li-ion batteries because of the shortened diffusion path and access to nonequilibrium routes for fast Li incorporation, thus radically boosting power density of the electrodes. However, how Li intercalation occurs locally in a single nanoparticle of such materials remains unresolved because real-time observation at such a fine scale is still lacking. We report visualization of local Li intercalation via solid-solution transformation in individual Li x FePO4 nanoparticles, enabled by probing sub-angstrom changes in the lattice spacing in situ. The real-time observation reveals inhomogeneous intercalation, accompanied with an unexpected reversal of Li concentration at the nanometer scale. The origin of the reversal phenomenon is elucidated through phase-field simulations, and it is attributed to the presence of structurally different regions that have distinct chemical potential functions. The findings from this study provide a new perspective on the local intercalation dynamics in battery electrodes.},
 bibtype = {article},
 author = {Zhang, Wei and Yu, Hui-Chia and Wu, Lijun and Liu, Hao and Abdellahi, Aziz and Qiu, Bao and Bai, Jianming and Orvananos, Bernardo and Strobridge, Fiona C. and Zhou, Xufeng and Liu, Zhaoping and Ceder, Gerbrand and Zhu, Yimei and Thornton, Katsuyo and Grey, Clare P. and Wang, Feng},
 doi = {10.1126/sciadv.aao2608},
 journal = {Science Advances},
 number = {1}
}

Nanoparticulate electrodes, such as Li x FePO4, have unique advantages over their microparticulate counterparts for the applications in Li-ion batteries because of the shortened diffusion path and access to nonequilibrium routes for fast Li incorporation, thus radically boosting power density of the electrodes. However, how Li intercalation occurs locally in a single nanoparticle of such materials remains unresolved because real-time observation at such a fine scale is still lacking. We report visualization of local Li intercalation via solid-solution transformation in individual Li x FePO4 nanoparticles, enabled by probing sub-angstrom changes in the lattice spacing in situ. The real-time observation reveals inhomogeneous intercalation, accompanied with an unexpected reversal of Li concentration at the nanometer scale. The origin of the reversal phenomenon is elucidated through phase-field simulations, and it is attributed to the presence of structurally different regions that have distinct chemical potential functions. The findings from this study provide a new perspective on the local intercalation dynamics in battery electrodes.

@article{
 title = {Identifying the chemical and structural irreversibility in LiNi 0.8 Co 0.15 Al 0.05 O 2 – a model compound for classical layered intercalation},
 type = {article},
 year = {2018},
 pages = {4189-4198},
 volume = {6},
 websites = {http://pubs.rsc.org/en/content/articlepdf/2018/ta/c7ta10829j,http://xlink.rsc.org/?DOI=C7TA10829J},
 id = {5334cdae-e440-3612-a2e6-54182803b3ef},
 created = {2018-02-12T16:38:15.819Z},
 accessed = {2018-02-12},
 file_attached = {true},
 profile_id = {acecf9ac-a9eb-39c3-b1a6-bdadc9df448a},
 last_modified = {2020-05-13T14:36:25.021Z},
 read = {true},
 starred = {false},
 authored = {true},
 confirmed = {true},
 hidden = {false},
 folder_uuids = {b7fc39ea-b907-41ad-867d-d41108aaba7d},
 private_publication = {false},
 abstract = {Anisotropic disorder along the c -axis results from static disorder.},
 bibtype = {article},
 author = {Liu, Haodong and Liu, Hao and Seymour, Ieuan D and Chernova, Natasha and Wiaderek, Kamila M and Trease, Nicole M and Hy, Sunny and Chen, Yan and An, Ke and Zhang, Minghao and Borkiewicz, Olaf J and Lapidus, Saul H and Qiu, Bao and Xia, Yonggao and Liu, Zhaoping and Chupas, Peter J and Chapman, Karena W and Whittingham, M Stanley and Grey, Clare P and Meng, Ying Shirley},
 doi = {10.1039/C7TA10829J},
 journal = {Journal of Materials Chemistry A},
 number = {9}
}

Anisotropic disorder along the c -axis results from static disorder.

@article{
 title = {Identifying the chemical and structural irreversibility in LiNi<sub>0.8</sub>Co<sub>0.15</sub>Al<sub>0.05</sub>O<sub>2</sub> – a model compound for classical layered intercalation},
 type = {article},
 year = {2018},
 pages = {4189-4198},
 volume = {6},
 websites = {http://pubs.rsc.org/en/content/articlepdf/2018/TA/C7TA10829J,http://xlink.rsc.org/?DOI=C7TA10829J,http://pubs.rsc.org/en/content/articlepdf/2018/ta/c7ta10829j},
 id = {4b31512f-2d29-3513-a6aa-8ab34475c402},
 created = {2020-03-30T20:06:32.566Z},
 accessed = {2018-02-12},
 file_attached = {true},
 profile_id = {acecf9ac-a9eb-39c3-b1a6-bdadc9df448a},
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 confirmed = {true},
 hidden = {false},
 folder_uuids = {b7fc39ea-b907-41ad-867d-d41108aaba7d},
 private_publication = {false},
 abstract = {Anisotropic disorder along the c -axis results from static disorder.},
 bibtype = {article},
 author = {Liu, Haodong and Liu, Hao and Seymour, Ieuan D and Chernova, Natasha and Wiaderek, Kamila M and Trease, Nicole M and Hy, Sunny and Chen, Yan and An, Ke and Zhang, Minghao and Borkiewicz, Olaf J and Lapidus, Saul H and Qiu, Bao and Xia, Yonggao and Liu, Zhaoping and Chupas, Peter J and Chapman, Karena W and Whittingham, M Stanley and Grey, Clare P and Meng, Ying Shirley},
 doi = {10.1039/C7TA10829J},
 journal = {Journal of Materials Chemistry A},
 number = {9}
}

Anisotropic disorder along the c -axis results from static disorder.

@article{
 title = {Intergranular Cracking as a Major Cause of Long-Term Capacity Fading of Layered Cathodes},
 type = {article},
 year = {2017},
 keywords = {batteries,capacity fading,discharge,eventually,hundreds of charge,intergranular cracking,lead to failure,may occur progressively over,operando x-ray di ff,or energy storage within,raction,the processes that,undermine performance and},
 pages = {3452-3457},
 volume = {17},
 websites = {http://pubs.acs.org/doi/abs/10.1021/acs.nanolett.7b00379},
 month = {6},
 day = {14},
 id = {83e34f23-3380-3496-90e6-f5cccfdd95e6},
 created = {2017-06-21T14:47:00.701Z},
 file_attached = {true},
 profile_id = {acecf9ac-a9eb-39c3-b1a6-bdadc9df448a},
 last_modified = {2017-10-25T02:22:46.600Z},
 read = {true},
 starred = {false},
 authored = {true},
 confirmed = {true},
 hidden = {false},
 private_publication = {false},
 bibtype = {article},
 author = {Liu, Hao and Wolf, Mark and Karki, Khim and Yu, Young-sang and Stach, Eric A and Cabana, Jordi and Chapman, Karena W and Chupas, Peter J},
 doi = {10.1021/acs.nanolett.7b00379},
 journal = {Nano Letters},
 number = {6}
}

@article{
 title = {Sensitivity and Limitations of Structures from X-ray and Neutron-Based Diffraction Analyses of Transition Metal Oxide Lithium-Battery Electrodes},
 type = {article},
 year = {2017},
 pages = {A1802-A1811},
 volume = {164},
 websites = {http://jes.ecsdl.org/content/164/9/A1802.abstract,https://iopscience.iop.org/article/10.1149/2.0271709jes},
 month = {6},
 day = {21},
 id = {812a6479-0524-364c-a891-4806283b833c},
 created = {2017-06-25T15:46:55.153Z},
 file_attached = {true},
 profile_id = {acecf9ac-a9eb-39c3-b1a6-bdadc9df448a},
 last_modified = {2020-06-19T19:47:57.597Z},
 read = {true},
 starred = {false},
 authored = {true},
 confirmed = {true},
 hidden = {false},
 private_publication = {false},
 abstract = {Lithium transition metal oxides are an important class of electrode materials for lithium-ion batteries. Binary or ternary (transition) metal doping brings about new opportunities to improve the electrode's performance and often leads to more complex stoichiometries and atomic structures than the archetypal LiCoO2. Rietveld structural analyses of X-ray and neutron diffraction data is a widely-used approach for structural characterization of crystalline materials. However, different structural models and refinement approaches can lead to differing results, and some parameters can be difficult to quantify due to the inherent limitations of the data. Here, through the example of LiNi0.8Co0.15Al0.05O2 (NCA), we demonstrated the sensitivity of various structural parameters in Rietveld structural analysis to different refinement approaches and structural models, and proposed an approach to reduce refinement uncertainties due to the inexact X-ray scattering factors of the constituent atoms within the lattice. This refinement approach was implemented for electrochemically-cycled NCA samples and yielded accurate structural parameters using only X-ray diffraction data. The present work provides the best practices for performing structural refinement of lithium transition metal oxides.},
 bibtype = {article},
 author = {Liu, Hao and Liu, Haodong and Lapidus, Saul H and Meng, Y Shirley and Chupas, Peter J and Chapman, Karena W},
 doi = {10.1149/2.0271709jes},
 journal = {Journal of The Electrochemical Society},
 number = {9}
}

Lithium transition metal oxides are an important class of electrode materials for lithium-ion batteries. Binary or ternary (transition) metal doping brings about new opportunities to improve the electrode's performance and often leads to more complex stoichiometries and atomic structures than the archetypal LiCoO2. Rietveld structural analyses of X-ray and neutron diffraction data is a widely-used approach for structural characterization of crystalline materials. However, different structural models and refinement approaches can lead to differing results, and some parameters can be difficult to quantify due to the inherent limitations of the data. Here, through the example of LiNi0.8Co0.15Al0.05O2 (NCA), we demonstrated the sensitivity of various structural parameters in Rietveld structural analysis to different refinement approaches and structural models, and proposed an approach to reduce refinement uncertainties due to the inexact X-ray scattering factors of the constituent atoms within the lattice. This refinement approach was implemented for electrochemically-cycled NCA samples and yielded accurate structural parameters using only X-ray diffraction data. The present work provides the best practices for performing structural refinement of lithium transition metal oxides.

@article{
 title = {Effects of Antisite Defects on Li Diffusion in LiFePO<sub>4</sub> Revealed by Li Isotope Exchange},
 type = {article},
 year = {2017},
 pages = {12025-12036},
 volume = {121},
 websites = {http://pubs.acs.org/doi/abs/10.1021/acs.jpcc.7b02819,https://pubs.acs.org/doi/10.1021/acs.jpcc.7b02819},
 month = {6},
 day = {8},
 id = {fbdcf5d6-b259-3524-b4d6-679bb14f5c5f},
 created = {2017-07-09T15:37:14.250Z},
 file_attached = {true},
 profile_id = {acecf9ac-a9eb-39c3-b1a6-bdadc9df448a},
 last_modified = {2020-08-06T13:30:33.491Z},
 read = {true},
 starred = {false},
 authored = {true},
 confirmed = {true},
 hidden = {false},
 private_publication = {false},
 bibtype = {article},
 author = {Liu, Hao and Choe, Min-Ju and Enrique, Raul A. and Orvañanos, Bernardo and Zhou, Lina and Liu, Tao and Thornton, Katsuyo and Grey, Clare P.},
 doi = {10.1021/acs.jpcc.7b02819},
 journal = {The Journal of Physical Chemistry C},
 number = {22}
}

@article{
 title = {Reaction Heterogeneity in LiNi<sub>0.8</sub>Co<sub>0.15</sub>Al<sub>0.05</sub>O<sub>2</sub> Induced by Surface Layer},
 type = {article},
 year = {2017},
 pages = {7345-7352},
 volume = {29},
 websites = {http://pubs.acs.org/doi/pdfplus/10.1021/acs.chemmater.7b02236,http://pubs.acs.org/doi/10.1021/acs.chemmater.7b02236,https://pubs.acs.org/doi/10.1021/acs.chemmater.7b02236},
 month = {9},
 day = {12},
 id = {60b70238-32d8-3680-8372-faeadfdb81b4},
 created = {2017-12-12T21:35:29.770Z},
 accessed = {2017-12-12},
 file_attached = {true},
 profile_id = {acecf9ac-a9eb-39c3-b1a6-bdadc9df448a},
 last_modified = {2020-08-06T13:30:33.704Z},
 read = {true},
 starred = {false},
 authored = {true},
 confirmed = {true},
 hidden = {false},
 private_publication = {false},
 abstract = {Through operando synchrotron powder X-ray diffraction (XRD) analysis of layered transition metal oxide electrodes of composition LiNi 0.8 Co 0.15 Al 0.05 O 2 (NCA), we decouple the intrinsic bulk reaction mechanism from surface-induced effects. For identically prepared and cycled electrodes stored in different environments, we demonstrate that the intrinsic bulk reaction for pristine NCA follows solid-solution mechanism, not a two-phase as suggested previously. By combining high resolution powder X-ray diffraction, diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS), and surface sensitive X-ray photoelectron spectroscopy (XPS), we demonstrate that adventitious Li 2 CO 3 forms on the electrode particle surface during exposure to air through reaction with atmospheric CO 2 . This surface impedes ionic and electronic transport to the underlying electrode, with progressive erosion of this layer during cycling giving rise to different reaction states in particles with an intact versus an eroded Li 2 CO 3 surface-coating. This reaction heterogeneity, with a bimodal distribution of reaction states, has previously been interpreted as a " two-phase " reaction mechanism for NCA, as an activation step that only occurs during the first cycle. Similar surface layers may impact the reaction mechanism observed in other electrode materials using bulk probes such as operando powder XRD. ■ INTRODUCTION Decoupling the energy storage behavior intrinsic to an electrode phase from variables related to material processing, battery architecture, and cycling parameters provides an important baseline from which we develop strategies to enhance battery performance. The kinetics and mechanism for Li extraction and insertion in a given electrode phase can be varied depending on the morphology of the active material, its surface chemistry (e.g., coatings), and the interface with the electrolyte. In the case of nanoscale LiFePO 4 particles, fast rate cycling can be achieved whereby the reaction proceeds via a solid-solution mechanism rather than the two-phase mecha-nism intrinsic to the bulk phase. 1 Accordingly, in probing the electrochemical reaction mechanism for an electrode phase, for example, through operando X-ray diffraction (XRD), it is imperative to differentiate intrinsic properties of the active material from extrinsic variables related to the material preparation and experimental protocol. Layered transition metal oxides, which provide high energy densities, are among the most important materials for commercial Li-ion batteries. These layered transition metal oxides span a number of phases distinguished by the layer stacking-sequence and interlayer cation geometry. For O3-type phases (α-NaFeO 2 structure type, R-3m), MO 2 layers containing mixed-metal cations (M = Mn, Fe, Co, Ni, Al) stack perpendicular to the c-direction in an ABC sequence, separated by interlayer Li + in octahedral O 2− environments.},
 bibtype = {article},
 author = {Grenier, Antonin and Liu, Hao and Wiaderek, Kamila M and Lebens-Higgins, Zachary W and Borkiewicz, Olaf J and Piper, Louis F J and Chupas, Peter J and Chapman, Karena W},
 doi = {10.1021/acs.chemmater.7b02236},
 journal = {Chemistry of Materials},
 number = {17}
}

Through operando synchrotron powder X-ray diffraction (XRD) analysis of layered transition metal oxide electrodes of composition LiNi 0.8 Co 0.15 Al 0.05 O 2 (NCA), we decouple the intrinsic bulk reaction mechanism from surface-induced effects. For identically prepared and cycled electrodes stored in different environments, we demonstrate that the intrinsic bulk reaction for pristine NCA follows solid-solution mechanism, not a two-phase as suggested previously. By combining high resolution powder X-ray diffraction, diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS), and surface sensitive X-ray photoelectron spectroscopy (XPS), we demonstrate that adventitious Li 2 CO 3 forms on the electrode particle surface during exposure to air through reaction with atmospheric CO 2 . This surface impedes ionic and electronic transport to the underlying electrode, with progressive erosion of this layer during cycling giving rise to different reaction states in particles with an intact versus an eroded Li 2 CO 3 surface-coating. This reaction heterogeneity, with a bimodal distribution of reaction states, has previously been interpreted as a " two-phase " reaction mechanism for NCA, as an activation step that only occurs during the first cycle. Similar surface layers may impact the reaction mechanism observed in other electrode materials using bulk probes such as operando powder XRD. ■ INTRODUCTION Decoupling the energy storage behavior intrinsic to an electrode phase from variables related to material processing, battery architecture, and cycling parameters provides an important baseline from which we develop strategies to enhance battery performance. The kinetics and mechanism for Li extraction and insertion in a given electrode phase can be varied depending on the morphology of the active material, its surface chemistry (e.g., coatings), and the interface with the electrolyte. In the case of nanoscale LiFePO 4 particles, fast rate cycling can be achieved whereby the reaction proceeds via a solid-solution mechanism rather than the two-phase mecha-nism intrinsic to the bulk phase. 1 Accordingly, in probing the electrochemical reaction mechanism for an electrode phase, for example, through operando X-ray diffraction (XRD), it is imperative to differentiate intrinsic properties of the active material from extrinsic variables related to the material preparation and experimental protocol. Layered transition metal oxides, which provide high energy densities, are among the most important materials for commercial Li-ion batteries. These layered transition metal oxides span a number of phases distinguished by the layer stacking-sequence and interlayer cation geometry. For O3-type phases (α-NaFeO 2 structure type, R-3m), MO 2 layers containing mixed-metal cations (M = Mn, Fe, Co, Ni, Al) stack perpendicular to the c-direction in an ABC sequence, separated by interlayer Li + in octahedral O 2− environments.

@article{
 title = {A radially accessible tubular in situ X-ray cell for spatially resolved operando scattering and spectroscopic studies of electrochemical energy storage devices},
 type = {article},
 year = {2016},
 keywords = {batteries,capacitors,cells,energy storage,in situ x-ray electrochemical,spatial},
 pages = {1665-1673},
 volume = {49},
 websites = {http://scripts.iucr.org/cgi-bin/paper?S1600576716012632},
 month = {10},
 publisher = {International Union of Crystallography},
 day = {1},
 id = {7136d096-8dba-3b7d-8023-b29d91d90745},
 created = {2016-09-22T20:26:36.000Z},
 file_attached = {true},
 profile_id = {acecf9ac-a9eb-39c3-b1a6-bdadc9df448a},
 last_modified = {2017-07-05T23:30:33.168Z},
 read = {true},
 starred = {false},
 authored = {true},
 confirmed = {true},
 hidden = {false},
 private_publication = {false},
 abstract = {A tubular operando electrochemical cell has been developed to allow spatially resolved X-ray scattering and spectroscopic measurements of individual cell components, or regions thereof, during device operation. These measurements are enabled by the tubular cell geometry, wherein the X-ray-transparent tube walls allow radial access for the incident and scattered/transmitted X-ray beam; by probing different depths within the electrode stack, the transformation of different components or regions can be resolved. The cell is compatible with a variety of synchrotron-based scattering, absorption and imaging methodologies. The reliability of the electrochemical cell and the quality of the resulting X-ray scattering and spectroscopic data are demonstrated for two types of energy storage: the evolution of the distribution of the state of charge of an Li-ion battery electrode during cycling is documented using X-ray powder diffraction, and the redistribution of ions between two porous carbon electrodes in an electrochemical double-layer capacitor is documented using X-ray absorption near-edge spectroscopy.},
 bibtype = {article},
 author = {Liu, Hao and Allan, Phoebe K. and Borkiewicz, Olaf J. and Kurtz, Charles and Grey, Clare P. and Chapman, Karena W. and Chupas, Peter J.},
 doi = {10.1107/S1600576716012632},
 journal = {Journal of Applied Crystallography},
 number = {5}
}

A tubular operando electrochemical cell has been developed to allow spatially resolved X-ray scattering and spectroscopic measurements of individual cell components, or regions thereof, during device operation. These measurements are enabled by the tubular cell geometry, wherein the X-ray-transparent tube walls allow radial access for the incident and scattered/transmitted X-ray beam; by probing different depths within the electrode stack, the transformation of different components or regions can be resolved. The cell is compatible with a variety of synchrotron-based scattering, absorption and imaging methodologies. The reliability of the electrochemical cell and the quality of the resulting X-ray scattering and spectroscopic data are demonstrated for two types of energy storage: the evolution of the distribution of the state of charge of an Li-ion battery electrode during cycling is documented using X-ray powder diffraction, and the redistribution of ions between two porous carbon electrodes in an electrochemical double-layer capacitor is documented using X-ray absorption near-edge spectroscopy.

@article{
 title = {Influence of particle size, cycling rate and temperature on the lithiation process of anatase TiO<sub>2</sub>},
 type = {article},
 year = {2016},
 pages = {6433-6446},
 volume = {4},
 websites = {http://xlink.rsc.org/?DOI=C6TA00673F},
 id = {0807977b-06f7-3ff5-b947-93178d44c5f0},
 created = {2017-03-10T18:29:06.000Z},
 file_attached = {true},
 profile_id = {acecf9ac-a9eb-39c3-b1a6-bdadc9df448a},
 last_modified = {2023-05-15T19:36:33.271Z},
 read = {true},
 starred = {false},
 authored = {true},
 confirmed = {true},
 hidden = {false},
 private_publication = {false},
 abstract = {A continuous structural change during the (de)lithiation of lithium-ion battery material, anatase TiO 2 , which undergoes a crystal symmetry change, was not found even at high rates.},
 bibtype = {article},
 author = {Liu, Hao and Grey, Clare P.},
 doi = {10.1039/C6TA00673F},
 journal = {Journal of Materials Chemistry A},
 number = {17}
}

A continuous structural change during the (de)lithiation of lithium-ion battery material, anatase TiO 2 , which undergoes a crystal symmetry change, was not found even at high rates.

@article{
 title = {Identifying the Distribution of Al 3+ in LiNi 0.8 Co 0.15 Al 0.05 O 2},
 type = {article},
 year = {2016},
 pages = {8170-8180},
 volume = {28},
 websites = {http://pubs.acs.org/doi/10.1021/acs.chemmater.6b02797,https://pubs.acs.org/doi/10.1021/acs.chemmater.6b02797},
 month = {11},
 day = {22},
 id = {21be8455-16a0-30df-ab07-088eb06f8c4a},
 created = {2017-04-06T15:15:00.353Z},
 file_attached = {true},
 profile_id = {acecf9ac-a9eb-39c3-b1a6-bdadc9df448a},
 last_modified = {2020-03-30T20:06:38.536Z},
 read = {true},
 starred = {false},
 authored = {true},
 confirmed = {true},
 hidden = {false},
 private_publication = {false},
 bibtype = {article},
 author = {Trease, Nicole M. and Seymour, Ieuan D. and Radin, Maxwell D. and Liu, Haodong and Liu, Hao and Hy, Sunny and Chernova, Natalya and Parikh, Pritesh and Devaraj, Arun and Wiaderek, Kamila M. and Chupas, Peter J. and Chapman, Karena W. and Whittingham, M. Stanley and Meng, Ying Shirley and Van der Van, Anton and Grey, Clare P.},
 doi = {10.1021/acs.chemmater.6b02797},
 journal = {Chemistry of Materials},
 number = {22}
}

@article{
 title = {Automatic Tuning Matching Cycler (ATMC) in situ NMR spectroscopy as a novel approach for real-time investigations of Li- and Na-ion batteries},
 type = {article},
 year = {2016},
 pages = {200-209},
 volume = {265},
 websites = {http://linkinghub.elsevier.com/retrieve/pii/S1090780716000902,https://linkinghub.elsevier.com/retrieve/pii/S1090780716000902},
 month = {4},
 id = {84ba320b-a5da-351d-ac32-ebc72f7c68a1},
 created = {2017-10-05T09:50:11.172Z},
 file_attached = {false},
 profile_id = {acecf9ac-a9eb-39c3-b1a6-bdadc9df448a},
 last_modified = {2020-01-29T03:23:53.500Z},
 read = {false},
 starred = {false},
 authored = {true},
 confirmed = {true},
 hidden = {false},
 private_publication = {false},
 bibtype = {article},
 author = {Pecher, Oliver and Bayley, Paul M. and Liu, Hao and Liu, Zigeng and Trease, Nicole M. and Grey, Clare P.},
 doi = {10.1016/j.jmr.2016.02.008},
 journal = {Journal of Magnetic Resonance}
}

@article{
 title = {Thermodynamics, Kinetics and Structural Evolution of ε-LiVOPO 4 over Multiple Lithium Intercalation},
 type = {article},
 year = {2016},
 pages = {1794-1805},
 volume = {28},
 websites = {http://pubs.acs.org/doi/abs/10.1021/acs.chemmater.5b04880,https://pubs.acs.org/doi/10.1021/acs.chemmater.5b04880},
 month = {3},
 day = {22},
 id = {ca54e089-5b70-3b66-8d8f-7e2735f109c6},
 created = {2017-10-05T09:50:11.179Z},
 file_attached = {true},
 profile_id = {acecf9ac-a9eb-39c3-b1a6-bdadc9df448a},
 last_modified = {2020-05-01T02:22:01.790Z},
 read = {true},
 starred = {false},
 authored = {true},
 confirmed = {true},
 hidden = {false},
 folder_uuids = {394f42fc-383a-41f1-a6ec-e92bbee26c33},
 private_publication = {false},
 bibtype = {article},
 author = {Lin, Yuh-Chieh and Wen, Bohua and Wiaderek, Kamila M. and Sallis, Shawn and Liu, Hao and Lapidus, Saul H. and Borkiewicz, Olaf J. and Quackenbush, Nicholas F. and Chernova, Natasha A. and Karki, Khim and Omenya, Fredrick and Chupas, Peter J. and Piper, Louis F. J. and Whittingham, M. Stanley and Chapman, Karena W. and Ong, Shyue Ping},
 doi = {10.1021/acs.chemmater.5b04880},
 journal = {Chemistry of Materials},
 number = {6}
}

@article{
 title = {Unraveling the Complex Delithiation Mechanisms of Olivine-Type Cathode Materials, LiFe x Co 1– x PO 4},
 type = {article},
 year = {2016},
 pages = {3676-3690},
 volume = {28},
 websites = {http://pubs.acs.org/doi/pdfplus/10.1021/acs.chemmater.6b00319,http://pubs.acs.org/doi/10.1021/acs.chemmater.6b00319},
 month = {6},
 day = {14},
 id = {74097762-b0bc-35ea-bc79-573a1ef22985},
 created = {2018-01-10T15:37:43.930Z},
 accessed = {2018-01-10},
 file_attached = {true},
 profile_id = {acecf9ac-a9eb-39c3-b1a6-bdadc9df448a},
 last_modified = {2018-03-06T15:59:33.232Z},
 read = {true},
 starred = {false},
 authored = {true},
 confirmed = {true},
 hidden = {false},
 folder_uuids = {b7fc39ea-b907-41ad-867d-d41108aaba7d},
 private_publication = {false},
 abstract = {The delithiation mechanisms occurring within the olivine-type class of cathode materials for Li-ion batteries have received considerable attention because of the good capacity retention at high rates for LiFePO 4 . A comprehensive mechanistic study of the (de)lithiation reactions that occur when the substituted olivine-type cathode materials LiFe x Co 1−x PO 4 (x = 0, 0.05, 0.125, 0.25, 0.5, 0.75, 0.875, 0.95, 1) are electro-chemically cycled is reported here using in situ X-ray diffraction (XRD) data and supporting ex situ 31 P NMR spectra. On the first charge, two intermediate phases are observed and identified: Li 1−x (Fe 3+) x (Co 2+) 1−x PO 4 for 0 < x < 1 (i.e., after oxidation of Fe 2+ to Fe 3+) and Li 2/3 Fe x Co 1−x PO 4 for 0 ≤ x ≤ 0.5 (i.e., the Co-majority materials). For the Fe-rich materials, we study how nonequilibrium, single-phase mechanisms that occur discretely in single particles, as observed for LiFePO 4 at high rates, are affected by Co substitution. In the Co-majority materials, a two-phase mechanism with a coherent interface is observed, as was seen in LiCoPO 4 , and we discuss how it is manifested in the XRD patterns. We then compare the nonequilibrium, single-phase mechanism with the bulk single-phase and coherent interface two-phase mechanisms. Despite the apparent differences between these mechanisms, we discuss how they are related and interconverted as a function of Fe/Co substitution and the potential implications for the electrochemistry of this system.},
 bibtype = {article},
 author = {Strobridge, Fiona C and Liu, Hao and Leskes, Michal and Borkiewicz, Olaf J and Wiaderek, Kamila M and Chupas, Peter J and Chapman, Karena W and Grey, Clare P},
 doi = {10.1021/acs.chemmater.6b00319},
 journal = {Chemistry of Materials},
 number = {11}
}

The delithiation mechanisms occurring within the olivine-type class of cathode materials for Li-ion batteries have received considerable attention because of the good capacity retention at high rates for LiFePO 4 . A comprehensive mechanistic study of the (de)lithiation reactions that occur when the substituted olivine-type cathode materials LiFe x Co 1−x PO 4 (x = 0, 0.05, 0.125, 0.25, 0.5, 0.75, 0.875, 0.95, 1) are electro-chemically cycled is reported here using in situ X-ray diffraction (XRD) data and supporting ex situ 31 P NMR spectra. On the first charge, two intermediate phases are observed and identified: Li 1−x (Fe 3+) x (Co 2+) 1−x PO 4 for 0 < x < 1 (i.e., after oxidation of Fe 2+ to Fe 3+) and Li 2/3 Fe x Co 1−x PO 4 for 0 ≤ x ≤ 0.5 (i.e., the Co-majority materials). For the Fe-rich materials, we study how nonequilibrium, single-phase mechanisms that occur discretely in single particles, as observed for LiFePO 4 at high rates, are affected by Co substitution. In the Co-majority materials, a two-phase mechanism with a coherent interface is observed, as was seen in LiCoPO 4 , and we discuss how it is manifested in the XRD patterns. We then compare the nonequilibrium, single-phase mechanism with the bulk single-phase and coherent interface two-phase mechanisms. Despite the apparent differences between these mechanisms, we discuss how they are related and interconverted as a function of Fe/Co substitution and the potential implications for the electrochemistry of this system.

@article{
 title = {Mapping the Inhomogeneous Electrochemical Reaction Through Porous LiFePO<sub>4</sub> -Electrodes in a Standard Coin Cell Battery},
 type = {article},
 year = {2015},
 pages = {2374-2386},
 volume = {27},
 websites = {http://pubs.acs.org/doi/abs/10.1021/cm504317a,http://pubs.acs.org/doi/10.1021/cm504317a},
 month = {4},
 day = {14},
 id = {f5c12cb3-e1ab-342b-a9ea-f97165ac5c03},
 created = {2015-11-02T20:42:38.000Z},
 file_attached = {true},
 profile_id = {acecf9ac-a9eb-39c3-b1a6-bdadc9df448a},
 last_modified = {2018-07-30T06:49:35.176Z},
 read = {true},
 starred = {false},
 authored = {true},
 confirmed = {true},
 hidden = {false},
 folder_uuids = {507d2a91-8340-4f2c-904d-e2cef3cd6b32},
 private_publication = {false},
 bibtype = {article},
 author = {Strobridge, Fiona C. and Orvananos, Bernardo and Croft, Mark and Yu, Hui-Chia and Robert, Rosa and Liu, Hao and Zhong, Zhong and Connolley, Thomas and Drakopoulos, Michael and Thornton, Katsuyo and Grey, Clare P.},
 doi = {10.1021/cm504317a},
 journal = {Chemistry of Materials},
 number = {7}
}

@article{
 title = {Capturing metastable structures during high-rate cycling of LiFePO₄ nanoparticle electrodes.},
 type = {article},
 year = {2014},
 pages = {1252817},
 volume = {344},
 websites = {http://www.ncbi.nlm.nih.gov/pubmed/24970091},
 month = {6},
 day = {27},
 id = {0ea44cef-5908-37ba-a248-71ccd4b13564},
 created = {2014-07-11T18:28:57.000Z},
 accessed = {2014-07-10},
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 last_modified = {2017-07-05T23:30:33.309Z},
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 abstract = {The absence of a phase transformation involving substantial structural rearrangements and large volume changes is generally considered to be a key characteristic underpinning the high-rate capability of any battery electrode material. In apparent contradiction, nanoparticulate LiFePO4, a commercially important cathode material, displays exceptionally high rates, whereas its lithium-composition phase diagram indicates that it should react via a kinetically limited, two-phase nucleation and growth process. Knowledge concerning the equilibrium phases is therefore insufficient, and direct investigation of the dynamic process is required. Using time-resolved in situ x-ray powder diffraction, we reveal the existence of a continuous metastable solid solution phase during rapid lithium extraction and insertion. This nonequilibrium facile phase transformation route provides a mechanism for realizing high-rate capability of electrode materials that operate via two-phase reactions.},
 bibtype = {article},
 author = {Liu, Hao and Strobridge, Fiona C and Borkiewicz, Olaf J and Wiaderek, Kamila M and Chapman, Karena W and Chupas, Peter J and Grey, Clare P},
 doi = {10.1126/science.1252817},
 journal = {Science (New York, N.Y.)}
}

The absence of a phase transformation involving substantial structural rearrangements and large volume changes is generally considered to be a key characteristic underpinning the high-rate capability of any battery electrode material. In apparent contradiction, nanoparticulate LiFePO4, a commercially important cathode material, displays exceptionally high rates, whereas its lithium-composition phase diagram indicates that it should react via a kinetically limited, two-phase nucleation and growth process. Knowledge concerning the equilibrium phases is therefore insufficient, and direct investigation of the dynamic process is required. Using time-resolved in situ x-ray powder diffraction, we reveal the existence of a continuous metastable solid solution phase during rapid lithium extraction and insertion. This nonequilibrium facile phase transformation route provides a mechanism for realizing high-rate capability of electrode materials that operate via two-phase reactions.