【摘要】 针对PVDF固态聚合物电解质离子电导率低和枝晶抑制能力差的问题,通过添加具有锂离子传输能力的铁电填料LiNbO₃来改善该电解质的性能。采用溶液浇铸法制备了不同LiNbO₃含量的PVDF-LiNbO₃复合固态电解质,并测试了它们的电化学性能。结果表明:LiNbO₃的加入提高了电解质的离子电导率,有效地抑制了枝晶生长,延长了电池寿命。当LiNbO₃的添加量为质量分数10%时,复合电解质在室温下的离子电导率可达6.1×10^-4 S·cm^-1,电化学窗口为4.5V,临界电流密度为1.8m A·cm^-2。使用该复合电解质组装的Li/Li对称电池在0.1m A·cm^-2和0.1m Ah·cm^-2的测试条件下,表现出超过800h的稳定循环和低于50mV的低极化电压。Li/NCM811全电池在1C倍率下稳定循环约400个周期后,容量保持率仍高达91.3%,表现出优异的循环性能。更多还原

【Abstract】 In order to solve the problems of low ion conductivity and poor dendrite inhibition ability of PVDF solid polymer electrolyte,the ferroelectric material LiNbO₃ with Li⁺ transport ability was used as a filler to improve the performance of PVDF polymer solid electrolyte.PVDF-LiNbO₃ composite solid electrolytes with different LiNbO₃ contents were prepared by solution casting method,and their electrochemical performance was tested.The results show that with the addition of LiNbO₃,the ionic conductivity of the electrolytes was significantly increased,the growth of Li dendrites was effectively inhibited,and the life of battery was extended.When LiNbO₃ content is 10%（mass fraction）,the composite solid electrolyte exhibits a high ionic conductivity of 6.1×10^-4 S·cm^-1at room temperature,a wide electrochemical window of 4.5V,and an increased critical current density of 1.8mA·cm^-2.The Li/Li symmetrical battery assembled with the composite electrolyte exhibits a stable cycle of more than 800h and a low polarization voltage of less than 50mV under the test conditions of 0.1m A·cm^-2 and 0.1 mAh·cm^-2.The capacity retention rate of Li/NCM811 full cell assembled with the composite electrolyte is as high as 91.3%after stable cycling for about400cycles at 1C,showing excellent cycle performance.更多还原