The unstable interfacial chemistry between the electrode and carbonate electrolyte greatly hinders the development of high-voltage lithium-ion batteries with a Ni-rich cathode. Herein, dimethyl sulfide (DMS), the simplest thioether, is successfully used as a new type of safe and low-cost electrolyte additive in a conventional carbonate electrolyte for high-voltage lithium-ion batteries. The electron-donating groups in DMS are capable of deactivating the reactive superoxide radical released from the cathode at high voltages and inducing robust S-rich cathode electrolyte interphase, which inhibits continuous side reactions, transition metal dissolutions, and cathode lattice oxygen consumption. As a result, the Li||NCM811 cell delivers a superior capacity retention of 85% at a voltage of 4.6 V over 300 cycles. Prolonged stable cycling for 1000 cycles (75% capacity retention) in a 4.4 V-level NCM811||Graphite full cell is enabled by DMS. The sulfide-based additive reported here provides a very promising and practical pathway to achieving a durable high-voltage lithium battery with a Ni-rich cathode.

中文翻译：

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二甲硫醚电解质添加剂启用的高压锂离子电池


电极和碳酸盐电解质之间不稳定的界面化学极大地阻碍了富镍正极高压锂离子电池的发展。其中，最简单的硫醚二甲硫醚（DMS）被成功地用作高压锂离子电池传统碳酸酯电解液中的新型安全且低成本的电解液添加剂。 DMS 中的供电子基团能够使高电压下从阴极释放的反应性超氧自由基失活，并诱导强大的富硫阴极电解质界面，从而抑制连续副反应、过渡金属溶解和阴极晶格氧消耗。因此，Li||NCM811 电池在 4.6 V 电压下经过 300 个循环后仍能保持 85% 的优异容量。通过 DMS，可以在 4.4 V 级 NCM811||石墨全电池中实现 1000 次循环的长时间稳定循环（75% 容量保留）。本文报道的硫化物添加剂为实现具有富镍阴极的耐用高压锂电池提供了一种非常有前途且实用的途径。