锂离子电池过充保护添加剂shuttle的研究

Study of shuttle as overcharge protection additive in lithium-ion battery

通过在锂离子电池电解液中添加2,5-二叔丁基-1,4-二甲氧基苯(2,5-diterbutyl-1,4-dimethoxybenzene,简称shuttle)来提高电池的过充保护能力。对磷酸铁锂电池分别进行了循环伏安扫描、常温循环寿命、过充后循环、交流阻抗测试,实验结果表明,在1 mol/L LiPF6/(EC+DEC+EMC)(1∶1∶1)+1%VC电解液中添加2%(质量分数)shuttle,当电压为3.81 V(相对于Li/Li+)时,shuttle开始发生氧化反应,烷氧基发生氧化离解,消耗电池内部过充的电量,提高了锂离子电池的安全性。此外,添加2%(质量分数)shuttle后电池循环性能有所提高,循环180次后,容量保持率从91.60%提高至94.70%。

2,5-diterbutyl-1,4-dimethoxybenzene(shuttle) as additive was added into Li-ion battery electrolyte in order to improve the ability of overcharge protection.The properties of the LiFePO4 battery were characterized by cyclic voltammetry,cycle performance at room temperature and electrochemical impedance spectrometry.The addition of 2% shuttle can be oxidized at about 3.81 V(vs.Li /Li+) in 1 mol/L LiPF6/(EC+DEC+EMC)(1∶1∶1) +1%VC electrolyte due to the cleavage of the alkoxy bond and consumption of the interior electric charge.Therefore,the overcharge protection in lithium-ion batteries can be achieved.Moreover,the capacity retention of lithium-ion batteries can be improved from 91.60% to 94.70% after 180 cycles.