一种水性负极黏结剂的合成及性能

黏结剂对电极的性能有着重要的影响。本文设计并制备了一种新型水性聚(乙烯-乙烯醇)-磺酸锂（EVOH-SO₃Li，简称ES-Li）电极黏结剂，并对其键接结构及组成进行分析；对其溶解性、电解液稳定性、热稳定性进行测试；对所制电极柔性、微观形貌及电化学性能进行研究。经与聚(乙烯-乙烯醇)（EVOH）及商业的聚偏氟乙烯（PVDF）黏结剂进行对比。结果表明：ES-Li水性黏结剂具有不溶解于电解液，热稳定性良好等优点；ES-Li黏结剂制备负极柔性及微观形貌优良，采用ES-Li作为负极黏结剂的电池在电化学稳定窗口、界面阻抗、首次循环效率、循环及倍率等方面均表现优异，ES-Li负极的首次库仑效率为89.93%，在1C下循环100次的容量保持率为96.93%，且在2C、5C倍率下的循环性能均优于EVOH及PVDF制备的负极，具有应用潜力及商业化前景。

Synthesis and performance of a kind of water soluble negative electrode binder

The binder has an important influence on the performance of the electrode. This paper designed and prepared a new type of water-based poly(ethylene-vinyl alcohol)-lithium sulfonate (EVOH-SO₃Li, ES-Li) electrode binder. Its bonding structure and composition, solubility, electrolyte stability and thermal stability were analyzed. The flexibility, microscopic morphology and electrochemical performance of the prepared electrode were studied. It was compared with poly(ethylene vinyl alcohol) (EVOH) and commercial polyvinylidene fluoride (PVDF) binders. The results showed that ES-Li water-based binder had the advantages of insoluble in electrolyte and good thermal stability. The negative electrode prepared by ES-Li binder had excellent flexibility and microscopic morphology. The battery using ES-Li as the negative electrode binder had excellent performance in electrochemical stability window, interface impedance, first cycle efficiency, cycle and rate, etc. The first coulombic efficiency of the anode with ES-Li was 89.93%, the capacity retention rate after 100 cycles of 1C was 96.93%, and the cycle performance at 2C and 5C rates was better than that of the anode prepared by EVOH and PVDF, which had application potential and commercialization prospects.