Li- and Mn-rich layered oxides are a promising class of cathode active materials (CAMs) for future lithium-ion batteries. However, they suffer from fast capacity fading in standard EC-containing electrolytes, and therefore fluorinated alternatives, such as FEC, are required to improve their full-cell performance, which unfortunately increases the cost of the electrolyte. In this study, we will analyze the reasons for the poor cycling performance of EC-containing electrolytes with CAMs that release lattice oxygen at high degrees of delithiation, i.e., either of Li- and Mn-rich NCMs (LMRNCMs) during activation or of NCMs at high cutoff voltages. By on-line electrochemical mass spectrometry (OEMS), we will show that the stability of EC towards electrochemical oxidation is sufficient up to potentials of ≈4.7 V vs Li + /Li, but that its chemical reaction with lattice oxygen released from CAMs negatively affects cycle-life. Furthermore, we will show that the use...

中文翻译：

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使用基于EC的富含Li和Mn的NCM电解质：O 2释放在选择环状碳酸酯方面的作用

富含锂和锰的层状氧化物是用于未来锂离子电池的有前途的一类阴极活性材料（CAM）。然而，它们在标准的含EC的电解质中容量快速下降，因此需要氟化替代品（如FEC）来改善其全电池性能，这不幸地增加了电解质的成本。在这项研究中，我们将分析含CAM的含EC的电解质循环性能差的原因，这些CAM在高脱锂度下释放晶格氧，即活化过程中的富Li和Mn的NCM（LMRNCM）或NCM在高截止电压下。通过在线电化学质谱（OEMS），我们将证明EC对电化学氧化的稳定性足以达到≈4.7V vs Li + / Li，但是它与从CAM释放出的晶格氧的化学反应会对循环寿命产生负面影响。此外，我们将展示使用...