Nitriles as efficient electrolyte additives are widely used in high-voltage lithium-ion batteries.However,their working mechanisms are still mysterious,especially in practical high-voltage LiCoO_(2)pouch lithium-ion b...Nitriles as efficient electrolyte additives are widely used in high-voltage lithium-ion batteries.However,their working mechanisms are still mysterious,especially in practical high-voltage LiCoO_(2)pouch lithium-ion batteries.Herein,we adopt a tridentate ligandcontaining 1,3,6-hexanetricarbonitrile(HTCN)as an effective electrolyte additive to shed light on the mechanism of stabilizing high-voltage LiCoO_(2)cathode(4.5 V)through nitriles.The LiCoO_(2)/graphite pouch cells with the HTCN additive electrolyte possess superior cycling performance,90%retention of the initial capacity after 800 cycles at 25℃,and 72%retention after 500 cycles at 45℃,which is feasible for practical application.Such an excellent cycling performance can be attributed to the stable interface:The HTCN molecules with strong electron-donating ability participate in the construction of cathode-electrolyte interphase(CEI)through coordinating with Co ions,which suppresses the decomposition of electrolyte and improves the structural stability of LiCoO_(2)during cycling.In summary,the work recognizes a coordinating-based interphase-forming mechanism as an effective strategy to optimize the performance of high voltage LiCoO_(2)cathode with appropriate electrolyte additives for practical pouch batteries.展开更多
基金supported by the National Key Research and Development Program of China(Nos.2017YFA0206700 and 2017YFA0402802)the National Natural Science Foundation of China(Nos.21776265 and 51902304)Anhui Provincial Natural Science Foundation(No.1908085ME122).
文摘Nitriles as efficient electrolyte additives are widely used in high-voltage lithium-ion batteries.However,their working mechanisms are still mysterious,especially in practical high-voltage LiCoO_(2)pouch lithium-ion batteries.Herein,we adopt a tridentate ligandcontaining 1,3,6-hexanetricarbonitrile(HTCN)as an effective electrolyte additive to shed light on the mechanism of stabilizing high-voltage LiCoO_(2)cathode(4.5 V)through nitriles.The LiCoO_(2)/graphite pouch cells with the HTCN additive electrolyte possess superior cycling performance,90%retention of the initial capacity after 800 cycles at 25℃,and 72%retention after 500 cycles at 45℃,which is feasible for practical application.Such an excellent cycling performance can be attributed to the stable interface:The HTCN molecules with strong electron-donating ability participate in the construction of cathode-electrolyte interphase(CEI)through coordinating with Co ions,which suppresses the decomposition of electrolyte and improves the structural stability of LiCoO_(2)during cycling.In summary,the work recognizes a coordinating-based interphase-forming mechanism as an effective strategy to optimize the performance of high voltage LiCoO_(2)cathode with appropriate electrolyte additives for practical pouch batteries.
