Dimethyl Sulfide Electrolyte Additive Enabled High-Voltage Lithium-Ion Battery

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.