Degradation Mechanisms in Li2VO2F Li-Rich Disordered Rock-Salt Cathodes
Degradation Mechanisms in Li2VO2F Li-Rich Disordered Rock-Salt Cathodes
复制标题
DOI：
10.1021/acs.chemmater.9b00829
复制
发表时间：
2019-08-27
影响因子：
8.6
通讯作者：
Hahlin, Maria
中科院分区：
文献类型：
--
作者：
Kallquist, Ida;Naylor, Andrew J.;Hahlin, Maria
锂离子电池中能量密度的增加特别依赖于迄今为止限制电池整体性能的阴极材料。一类新的材料，富含锂的无序岩盐，最近被提出作为下一代阴极的有希望的候选者，因为它们能够可逆地循环每个过渡金属多于一个锂离子。最近已经开发了这些富Li阴极材料的几种变体，并且显示出有希望的初始容量，但是关于循环期间的容量衰减和电压衰减的挑战尚未被克服。必须理解某些材料的显著容量衰减背后的机制，以允许设计可以减轻有害反应的新材料。在这项研究中，在富含锂的材料Li2VO2F的容量衰减的起源进行了调查，它被证明是开始与颗粒表面的降解，蔓延向内与继续循环。
The increased energy density in Li-ion batteries is particularly dependent on the cathode materials that so far have been limiting the overall battery performance. A new class of materials, Li-rich disordered rock salts, has recently been brought forward as promising candidates for next-generation cathodes because of their ability to reversibly cycle more than one Li-ion per transition metal. Several variants of these Li-rich cathode materials have been developed recently and show promising initial capacities, but challenges concerning capacity fade and voltage decay during cycling are yet to be overcome. Mechanisms behind the significant capacity fade of some materials must be understood to allow for the design of new materials in which detrimental reactions can be mitigated. In this study, the origin of the capacity fade in the Li-rich material Li2VO2F is investigated, and it is shown to begin with degradation of the particle surface that spreads inward with continued cycling.