电活性双酚A的合成及其锂离子电池防过充性能研究

对双酚A进行结构修饰,经甲醚化、氰基取代,设计合成了2,2-双-(4-(β-氰基乙氧基)苯基)丙烷（DBDCN）、2-(4-(β-氰基乙氧基)苯基)-2'-(4-甲氧基苯基)丙烷（DBMCN）和2,2-双-(4-甲氧基苯基)丙烷（DBMB）,将三种化合物作为锂离子电池的防过充添加剂开展研究。在锂离子电池电解液1 mol/L LiPF₆/[碳酸乙烯酯（EC）+ 碳酸二乙酯（DEC） + 碳酸甲乙酯（EMC） （1∶1∶1,体积比）]中分别添加0.1 mol/L的DBDCN、DBMB和DBMCN,采用循环伏安、过充测试、电化学阻抗、恒流充放电和扫描电子显微镜等手段研究DBDCN、DBMB和DBMCN的防过充性能,并探讨添加剂与正极材料LiFePO₄的相容性。这些化合物的氧化还原电位均为4.1 V,显著提高了电池的过充保护。100%过充测试和5 V截止电压测试结果表明,DBMB的防过充性能明显优于DBDCN和DBMCN。以0.5 C倍率电流循环100圈,基础电解液和分别添加0.1 M DBDCN、DBMB、DBMCN的电池放电比容量分别为134.5 mA∙h/g、135.3 mA∙h/g、132.8 mA∙h/g和127.0 mA∙h/g,容量保持率分别为87.7%、87.0%、89.5%和84.3%。结果表明,DBMB对电池防过充作用最明显。

Synthesis of Electro-Active Bisphenol A Compounds and Overcharge Protection Performances in Lithium-Ion Batteries

2,2-Bis-(4-(β-cyan-ethoxy)-phenyl)-propane (DBDCN), 2-(4-(β-cyan-ethoxy)-phenyl)-2'-(4-methoxyphenyl)propane (DBMCN) and 2,2-bis(4-methoxyphenyl)propane (DBMB) were synthesized by modifying bisphenol A through a Michael addition reaction using acrylonitrile or methyl etherification using dimethyl sulfate. These compounds were explored as new redox shuttle additives for overcharge protection in lithium-ion batteries. Cyclic voltammetry (CV), overcharge test, electrochemical impedance spectrum (EIS), charge-discharge cycle performance, and scanning electron microscopy (SEM) were carried out to investigate the electrochemical performances, and the compatibility of these additives in the electrolyte with LiFePO₄ electrode. These three compounds had a working potential of 4.1 V (vs Li/Li⁺), and showed significantly improved overcharge protection performance when used as additive (0.1 M) in 1 mol/L LiPF₆/ [ethylene carbonate (EC) + diethyl carbonate (DEC) + ethylmethyl carbonate (EMC) (1:1:1, by volume)]. Among them, DBMB exhibited best overcharge protection performance in 100% overcharge at 5 V cutoff voltage. After 100 cycles at 0.5 C rate, the capacity retention for LiFePO₄/Li cell, using the base electrolyte and the electrolyte with 0.1 M DBDCN, 0.1 M DBMB and 0.1 M DBMCN additive, were 87.7%, 87.0%, 89.5% and 84.3%, respectively.