Wu Vincent C, Zhong Peichen, Ong Julia, Yoshida Eric, Kwon Andrew, Ceder Gerbrand, Clément Raphaële J
Department of Materials Science and Engineering, University of California-Berkeley, Berkeley, California 94720, United States.
Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States.
ACS Energy Lett. 2024 May 30;9(6):3027-3035. doi: 10.1021/acsenergylett.4c01075. eCollection 2024 Jun 14.
Disordered rocksalt oxide (DRX) cathodes are promising candidates for next-generation Co- and Ni-free Li-ion batteries. While fluorine substitution for oxygen has been explored as an avenue to enhance their performance, the amount of fluorine incorporated into the DRX structure is particularly challenging to quantify and impedes our ability to relate fluorination to electrochemical performance. Herein, an experimental-computational method combining Li and F solid-state nuclear magnetic resonance, and cluster expansion Monte Carlo simulations, is developed to determine the composition of DRX oxyfluorides. Using this method, the synthesis of Mn- and Ti-containing DRX via standard high temperature sintering and microwave heating is optimized. Further, the upper fluorination limit attainable using each of these two synthesis routes is established for various Mn-rich DRX compounds. A comparison of their electrochemical performance reveals that the capacity and capacity retention mostly depend on the Mn content, while fluorination plays a secondary role.
无序岩盐氧化物（DRX）阴极是下一代无钴和无镍锂离子电池的有前途的候选材料。虽然氟取代氧已被探索为提高其性能的途径，但纳入DRX结构中的氟量特别难以量化，这阻碍了我们将氟化与电化学性能联系起来的能力。在此，开发了一种结合锂和氟固态核磁共振以及团簇展开蒙特卡罗模拟的实验-计算方法，以确定DRX氧氟化物的组成。使用该方法，通过标准高温烧结和微波加热优化了含锰和钛的DRX的合成。此外，针对各种富锰DRX化合物，确定了使用这两种合成路线中每种路线可达到的最高氟化限度。对它们的电化学性能进行比较后发现，容量和容量保持率主要取决于锰含量，而氟化起次要作用。
