@article{35890,
  author = {Tzu‐Yang Huang and Zijian Cai and Matthew J Crafton and Lori A Kaufman and Zachary M Konz and Helen K Bergstrom and Elyse A Kedzie and Han‐Ming Hao and Gerbrand Ceder and Bryan D McCloskey},
  title = {Quantitative Decoupling of Oxygen‐Redox and Manganese‐Redox Voltage Hysteresis in a Cation‐Disordered Rock Salt Cathode},
  abstract = {<p><span>Pronounced voltage hysteresis in Li-excess cathode materials is commonly thought to be associated with oxygen redox. However, these materials often possess overlapping oxygen and transition-metal redox, whose contributions to hysteresis between charge and discharge are challenging to distinguish. In this work, a two-step aqueous redox titration is developed with the aid of mass spectrometry (MS) to quantify oxidized lattice oxygen and Mn</span><span><sup>3+</sup> /<sup>4+</sup></span><span>&nbsp;redox in a representative Li-excess cation-disordered rock salt—Li</span><sub><span>1.2</span></sub><span>Mn</span><sub><span>0.4</span></sub><span>Ti</span><sub><span>0.4</span></sub><span>O</span><sub><span>2</span></sub><span>&nbsp;(LMTO). Two MS-countable gas molecules evolve from two separate titrant-analyte reactions, thereby allowing Mn and O redox capacities to be decoupled. The decoupled O and Mn redox coulombic efficiencies are close to 100% for the LMTO cathode, indicating high charge-compensation reversibility. As incremental Mn and O redox capacities are quantitatively decoupled, each redox voltage hysteresis is further evaluated. Overall, LMTO voltage hysteresis arises not only from an intrinsic charge-discharge voltage mismatch related to O redox, but also from asymmetric Mn-redox overvoltages. The results reveal that O and Mn redox both contribute substantially to voltage hysteresis. This work further shows the potential of designing new analytical workflows to experimentally quantify key properties, even in a disordered material having complex local coordination&nbsp;environments.</span></p>},
  year = {2023},
  journal = {Advanced Energy Materials},
  volume = {13},
  month = {06/2023},
  issn = {1614-6832},
  url = {https://onlinelibrary.wiley.com/toc/16146840/13/21},
  doi = {10.1002/aenm.202300241},
  language = {eng},
}