新型添加剂全氟辛酸铵对提高锂离子电池安全性能的研究

报导可显著提高锂离子电池安全性的新型电解液添加剂全氟辛酸铵(APC). UL 94 可燃性试验显示添加0.70 wt% APC能使有机电解液的火焰传播速率下降33%. 差示扫描量热法(DSC)测试表明APC显著减弱了嵌锂碳电极和电解液之间的放热反应, 并将其热不稳定温度由138.0 ℃提高到167.5 ℃. 交流阻抗检测显示APC的加入明显降低了碳材料电极的界面阻抗, 并且提高了在储存过程中其固态电解质界面(SEI)层的稳定性. 添加APC还能有效地提高Li/MCMB电池充放电循环性能和库仑效率.

Study on a Novel Electrolyte Additive Ammonium Perfluorocaprylate to Improve the Safety of Lithium-ion Battery

This paper firstly revealed that the safety of lithium-ion battery could be greatly improved by using a novel electrolyte additive: ammonium perfluorocaprylate (APC). In a UL 94 flammability test, even with APC concentration in an organic electrolyte as low as 0.70 wt%, the flame propagation rate was significantly decreased by about 33%. The differential scanning calorimetry (DSC) analysis showed that less heat released in the reaction between lithiated Mesocarbon microbead (MCMB) anode and electrolyte, and the thermal unstable temperature of electrolyte increased from 138.0 to 167.5 ℃ by adding APC in the electrolyte. A lower charge-transfer resistance of an MCMB anode and a higher stability of SEI film were well determined by EIS in the APC-containing electrolyte system. The Li/MCMB cell with additive APC presented better capability of capacity retention and charge-discharge coulombic efficiency in cycling testing.