Modified ether electrolyte by siloxane additive with abundant Si-O bonds for high-voltage lithium metal batteries

Abstract To overcome the oxidative instability and performance degradation of ether-based electrolytes in lithium-metal batteries operating at high voltages (>4 V vs. Li/Li + ), decamethylcyclopentasiloxane (DMCPS) was introduced as an electrolyte additive in this study. The experimental results show that the lithium deposition behaviour is significantly optimized, and the electrochemical performance of the Li-metal battery is significantly enhanced by the incorporation of this additive. The capacity retention rate of batteries increases from 70.8% in ether electrolyte system (LS-009) to 73.9% in DMCPS additive system (LS-009-DMCPS) after 700 cycles at 0.5 C current in the voltage range of 2.6-3.8 V. More impressively, the capacity retention of Li/NCM811(LiNi 0.8 Mn 0.1 Co 0.1 O 2 ) batteries using LS-009 system is only 70% after 20 cycles, while it increases to 75% in system with DMCPS after 100 cycles at a current density of 0.5 C under the operating condition of 3.0-4.3 V. These results well suggest that the incorporation of DMCPS effectively improves the high-voltage stability of ether electrolyte. Overall, the findings highlight the effectiveness of DMCPS in stabilizing the electrode-electrolyte interface in ether electrolyte and provide valuable guidance for the design of high-performance ether-based lithium-metal batteries.