Abstract
Sulfurized polyacrylonitrile(SPAN)is proposed as a promising cathode material for lithium sulfur bat-teries.However,the continuous side reactions at the electrolyte-electrode interfaces as well as the slow redox kinetics of SPAN cathode deteriorate the electrochemical performance.In this study,an electrolyte with dual-additives comprising 2-fluoropyridine(2-FP)and lithium difluorobis(oxalato)phosphate(LiDF-BOP)was used to improve the performance of Li‖ SPAN cells.2-FP has a lower lowest occupied molecular orbital energy than that of the solvents in the electrolyte,leading to its prior reduction.A LiF-rich film can be formed on the electrode,effectively improving the stability of the electrolyte-electrode interfaces and prolonging the life.Simultaneously,LiDFBOP could form an electrolyte-electrode interface film contain-ing a large amount of LixPOyFz species,compensating for the kinetic deterioration caused by the lower ionic conductive of LiF formed at the electrolyte-electrode interface.Hence,an electrode-interface film with good chemical stability and high Li+transport was established by LiF and LixPOyFz-rich species.The Li‖SPAN cell with the electrolyte containing dual-additives demonstrates an excellent capacity retention of 97.5％after 200 cycles at 1.0 C,25 ℃,comparing to 56.2％capacity retention without additives.More-over,the rate capacities of cells with dual-additives can reach 1128.1 mAh/g at 5 C,comparing to only 813.5 mAh/g using electrolyte without additives.Our results shown that the dual-additives in electrolyte provide a promising strategy for practical application of lithium sulfur batteries with SPAN cathodes.
基金项目
国家自然科学基金(52072378)
国家自然科学基金(22209189)
国家重点研发计划(2022YFB3803400)
中国科学院战略规划重点项目(XDA22010602)
中国科学院战略规划重点项目(2022YFB3803400)
Shenyang Science and Technology Program(22-322-3-19)
维普
万方数据