阻燃电解液改善钛酸锂电池体系热稳定性研究

为了提高锂离子电池安全性,将碳酸亚乙烯酯、亚硫酸丙烯酯与二甲基乙酰胺加入到1.0mol/L LiPF_6/碳酸乙烯酯+碳酸二乙酯(1∶1wt%)的基准电解液中,配制成阻燃电解液。运用C80微量量热仪对钛酸锂负极(放电至1.0V)与基准电解液共存体系、钛酸锂负极(放电至1.0V)与阻燃电解液共存体系进行热稳定性测试,并计算得到热力学参数。对Li/基准电解液/Li_4Ti_5O_(12)和Li/阻燃电解液/Li_4Ti_5O_(12)半电池进行充放电循环测试、循环伏安测试与SEM扫描电镜测试。实验结果表明,钛酸锂负极与阻燃电解液体系反应放出的热量较钛酸锂负极与基准电解液体系减少了35.4%,且具有更高的活化能,提高了钛酸锂电池体系的热稳定性;同时电化学测试结果表明,阻燃电解液与钛酸锂负极有良好的相容性,可以应用到钛酸锂电池体系。

Flame-retardant electrolyte to improve the thermal stability of Li4Ti5O12 battery

To improve the safety of lithium ion battery, vinylene carbonate, 1,3-propylene sulfite and dimethylacetamide are used in the baseline electrolyte (1.0 mol/L LiPF6 / ethylene carbonate + diethyl carbonate (1:1wt%)). The electrolyte with the additives added is named as flame-retardant electrolyte. The thermal stabilities of fully discharged Li4Ti5O12 mixed with the baseline electrolyte and flame-retardant electrolyte, respectively, are investigated using a C80 micro calorimeter, and the thermodynamics parameters are calculated. The electrochemical performances of the Li /baseline electrolyte/ Li4Ti5O12 and Li /flame-retardant electrolyte/ Li4Ti5O12 half cells are evaluated using glavanostatic charge/discharge, cyclic voltammetry and SEM. The experimental results demonstrate that the fully discharged Li4Ti5O12-flame-retardant electrolyte system releases less heat, with a reduction of 35.4%, with higher activation energy, which can improve the thermal stability of Li4Ti5O12battery. Moreover, the flame-retardant electrolyte has a good stability and compatibility on the Li4Ti5O12 anode electrode, and hence, it can be used in the Li4Ti5O12 battery.