【摘要】 高电压钴酸锂(LCO)正极材料是消费锂离子电池重要研究方向。其优势是使电池具有高的能量密度,能进一步延长电子设备的待机时间,但循环寿命和电池安全面临严峻挑战,亟需材料和电解液改性以提高LCO在高电位下的稳定性和电池安全性。本文研究了乙氧基五氟环磷腈(PFPN)作为多功能电解液添加剂对LCO在高电位下循环性能的影响,并进一步考察其电解液的阻燃特性。研究发现,电解液中添加5wt%的PFPN能显著提高LCO的高压循环稳定性,在4.5V(vs.Li/Li~+)下循环100次,容量保持率达到92%,而空白电解液为84%;此外,电解液添加PFPN后具有良好的阻燃效果,能有效提高LCO电池的安全性。结果表明PFPN是一种具有潜在应用价值的高电压和高安全的电解液添加剂。更多还原

【Abstract】 High-voltage lithium cobalt oxide(LCO)cathode material is an important research direction of consumer lithium-ion batteries.The advantage is that it can make higher battery energy density,extending the standby time of electronic devices.However,cycling life and safety are facing severe challenges.Material and electrolyte modification are urgently required to improve the stability of LCO at high potential and safety.In this study,the effect of ethoxy pentafluor of luorophos phazene(PFPN)as a multifunctional electrolyte additive on the cycling performance of LCO at high potential is investigated,and the flame-retardant properties are further investigated.We find that the addition of 5 wt% PFPN in the electrolyte can significantly improve the high-potential cycling stability of LCO.After cycling 100 times,the capacity retention rate reaches 92%at 4.5 V(vs.Li/Li+),while the blank electrolyte is only 84%.In addition,the electrolyte has a good flame-retardant effect after adding PFPN,which can effectively improve the safety of LCO batteries.These results indicate that PFPN is a good electrolyte additive for high voltage and safety battery application.更多还原