六氟磷酸锂浓度对锂离子电池性能的影响

Effects of Li PF_6 concentration on the performance of Li-ion battery

配制不同浓度（0.8~2.2 mol/L）的Li PF6/EC＋EMC＋DMC（质量比1∶1∶1）电解液,用循环伏安、电化学阻抗谱（EIS）和恒流充放电测试并结合Li^＋迁移数、电导率和黏度等参数的测试,研究锂盐浓度和电解液物化参数对电池倍率性能、循环性能的影响。电解液浓度为1.6~1.8 mol/L时,制得的锂离子电池倍率性能和循环性能最佳。电解液浓度为1.6 mol/L和1.8 mol/L的电池在3.65~2.00 V循环,20.0 C放电相对于0.5 C时的容量保持率分别为89.10%、91.1%;以1.0 C充电、10.0 C放电循环300次,容量保持率分别为56.22%、62.6%。

LiPF6/ EC ＋ EMC ＋ DMC（mass ratio was 1 ∶ 1 ∶ 1） electrolytes with different concentration（0. 8 ~ 2. 2 mol / L） were prepared,the effects of lithium salt concentration and electrolyte physicochemical parameters on the rate capability and cycle performance were studied by cyclic voltammetry,electrochemical impedance spectroscopy（EIS） and galvanostatic charge-discharge tests,along with parameters testing of Li^＋transference number,conductivity and viscosity. The Li-ion battery using electrolyte with salt concentration about 1. 6 ~ 1. 8 mol / L gave the best rate capability and cycle performance. When the batteries in which electrolyte concentration were 1. 6 mol / L,1. 8 mol / L cycled in 3. 65 ~ 2. 00 V,the capacity retention ratio of 20. 0 C discharge were 89. 10%and 91. 1% compared with 0. 5 C one,respectively,after 300 cycles at 1. 0 C charge and 10. 0 C discharge,the capacity retention ratio were 56. 22% and 62. 6%,respectively.