亲锂电解液在LiNi0.6Mn0.2Co0.2O2／Li二次锂金属电池中的电化学性能

金属锂电池被认为是具有良好前景的下一代高能量密度电池。然而，传统的碳酸酯类电解液与锂的亲和性差，在循环过程中由于锂枝晶的生长和固体电解质膜（SEI）的不稳定导致金属锂电池性能快速衰减。采用1.2 mol／L六氟磷酸锂（LiPF₆）／二氟草酸硼酸锂（LiDFOB）／氟代碳酸乙烯酯（FEC）／碳酸二乙酯（DEC），并添加了双三氟甲磺酰亚胺锂（LiTFSI）作为电解液，对其在LiNi_0.6Mn_0.2Co_0.2O₂／40 μm-Li（单位面积上负／正极材料的实际容量的比N／P＝2.85）电池中的电化学性能进行了研究。LiNi_0.6Mn_0.2Co_0.2O₂／40 μm-Li电池表现出优异的循环稳定性（循环120圈后，容量保持率>93%）和倍率性能（3C倍率下放电比容量为110 mA·h／g）。良好的电化学性能主要归因于该电解液可以在金属锂表面形成致密且稳定的SEI，并抑制锂枝晶的产生。

Electrochemical Performance of Lithiophilic Electrolyte in LiNi0.6Mn0.2Co0.2O2/Li Rechargeable Lithium Metal Battery

Lithium metal batteries are considered to be the next generation high-energy-density batteries with good prospects.However,the traditional carbonate-based electrolyte has poor compatibility with lithium,and the lithium metal battery has fast capacity decay due to the growth of lithium dendrites and the instability of the solid electrolyte interface(SEI)during cycling.Using 1.2 mol/L lithium hexafluorophosphate(LiPF₆)/lithium difluorooxalate(LiDFOB)/fluoroethylene carbonate(FEC)/diethylcarbonate(DEC),and lithium bis(trifluoromethanesulfonyl)imide(LiTFSI)added as an electrolyte,the electrochemical performance of LiNi_0.6Mn_0.2Co_0.2O₂/40μm-Li battery(ratio of negative to positive capacity per unit area N/P=2.85)was studied.The LiNi_0.6Mn_0.2Co_0.2O₂/40μm-Li battery exhibits excellent cycle stability(after 120 cycles,the capacity retention>93%)and rate performance(the specific discharge capacity is 110 mA·h/g at 3 C).The good electrochemical performance is mainly due to the fact that the electrolyte can form a dense and stable SEI on the surface of metal lithium and inhibit the generation of lithium dendrites.