School of Metallurgical and Ecological Engineering, University of Science and Technology Beijing, 100083 Beijing, China.
Key Laboratory of Organic Optoelectronics and Molecular Engineering, Department of Chemistry, Tsinghua University, 100084 Beijing, China.
ACS Appl Mater Interfaces. 2023 Jun 7;15(22):26627-26636. doi: 10.1021/acsami.3c02553. Epub 2023 May 23.
Lithium-rich layered oxides (LRLOs), with the chemical formula of LiMnO·(1 - )LiMO, delivering higher specific discharge capacity, are potential cathode materials for lithium-ion batteries. However, the dissolution of transition metal ions and the instability of the cathode-electrolyte interphase (CEI) hinder the commercial application of LRLOs. Herein, a simple and affordable method is developed for the construction of a robust CEI layer by quenching a kind of cobalt-free LRLO, LiNiFeMnO (denoted as NFM), in 1,1,2,2-tetrafluoroethyl-2,2,2-trifluoroethyl ether solvent. This robust CEI, with well-distributed LiF, TMF, and partial organic component CF, performs as a physical barrier to prevent NFM from direct contact with the electrolyte, suppresses the oxygen release, and ensures the CEI layer stability. The customized CEI with LiF and TMF-rich phase considerably enhances the NFM cycle stability and the initial coulomb efficiency and inhibits voltage fading. This work provides a valuable strategy for designing stable interface chemistry on the cathode of lithium-ion batteries.
富锂层状氧化物 (LRLOs)，其化学式为 LiMnO·(1 - )LiMO，具有更高的比放电容量，是锂离子电池的潜在阴极材料。然而，过渡金属离子的溶解和阴极-电解质界面（CEI）的不稳定性阻碍了 LRLOs 的商业应用。在此，通过将一种无钴富锂层状氧化物 LiNiFeMnO（表示为 NFM）在 1,1,2,2-四氟乙基-2,2,2-三氟乙基醚溶剂中淬火，开发了一种构建坚固 CEI 层的简单且经济实惠的方法。这种坚固的 CEI 具有分布均匀的 LiF、TMF 和部分有机成分 CF，起到物理屏障的作用，防止 NFM 与电解质直接接触，抑制氧气释放，并确保 CEI 层的稳定性。富含 LiF 和 TMF 的定制 CEI 极大地提高了 NFM 的循环稳定性和初始库仑效率，并抑制了电压衰减。这项工作为设计锂离子电池阴极的稳定界面化学提供了有价值的策略。
