乙炔黑修饰玻璃纤维隔膜及其在锂硫电池中的应用研究

Glass Fiber Separator Modified by Acetylene Black and Its Application in Lithium Sulfur Batteries

锂硫电池因其硫电极导电性差及容量衰减快等问题限制了其应用。为了提高锂硫电池的比容量、倍率性能及循环稳定性等电化学性能,本研究利用乙炔黑对玻璃纤维(GF)进行表面修饰,得到了一种新型的乙炔黑/玻璃纤维复合隔膜(CGF)。研究发现,在纯硫电极下,使用CGF隔膜的锂硫电池在电流密度为0.2C时,其起始比容量达到1550mAh/g。且在1C和2C高电流密度下,其比容量仍分别达到了960mAh/g和691mAh/g,长循环300圈后容量保持率分别为65%和58%。然而,使用GF隔膜的锂硫电池在0.2C时起始比容量仅为1113mAh/g。且其比容量衰减快,循环300圈后,比容量仅为517mAh/g;当电流密度增加到0.5C及以上时,锂硫电池基本不能释放容量。通过乙炔黑修饰玻璃纤维隔膜并将其应用于锂硫电池,有效地提高了电池的比容量、循环稳定性和倍率性能。

The application of lithium sulfur battery is restricted by the poor conductivity of sulfur electrode and its fast capacity fading. In order to improve the electrochemical properties of lithium sulfur batteries,such as specific capacity,rate capability,cycle stability,a new acetylene black/glass fiber composite separator（ CGF） was obtained by using acetylene black modified glass fiber（ GF） in this study. The results showed that the initial specific capacity of Li-S batteries with pure sulfur electrode reached 1550 m Ah/g at current density of 0. 2C when use CGF as separator. Even at high current density of 1C and 2C,the specific capacity also reached 960 mAh/g and 691 mAh/g,respectively. And exhibited an excellent cycling stability with 65 % and 58 % capacity retention after 300 cycles. However,the initial specific capacity of Li-S batteries only reached1113 m Ah/g at current density of 0. 2 C when use GF as separator. And its capacity fading was very fast. The capacity decreased to be 517 mAh/g after 300 cycles. When increased the current density to be 0. 5 C,the LiS batteries almost could not release any capacity. In this study,glass fiber separator modified by acetylene black and applied in lithium-sulfur batteries,the specific capacity,cycle stability and rate capability could be improved effectively.