碳纤维支撑柔性碳硫复合电极的制备、物性及电池性能研究

Flexible Carbon-fiber Supported Carbon–sulfur Electrode:Preparation, Physical Property and Electrochemical Performance

锂硫电池作为极具潜力的下一代二次电池受到广泛关注。然而,对于含硫正极的研究仍处于实验探索阶段,商业化的碳纤维毡应用于硫正极鲜有报道。本研究制备了锂硫电池用碳纤维支撑柔性碳硫复合电极,并对其进行了物性及电池性能的研究。结果发现,碳纤维毡具有多孔隙的三维网络结构,与具有微孔结构的多孔碳共同构成正极支撑体,能够物理固定正极材料,有助于提高电池的能量密度和锂硫正极的导电性,界面电阻由原来的97.9Ω降到22.6Ω。进一步研究表明,碳纤维毡做集流体的样品在首圈0.05C倍率下,具有996.7 mAh/g的放电比容量,在2C高倍率下循环140圈后仍保持666.7 mAh/g的放电比容量,而铝箔样品仅为772.9和471.6 mAh/g。同时,本研究使用的LA132水系粘结剂、super-P导电剂价格低廉,球磨制备工艺可规模化生产、安全环保,可以为锂硫电池工业化生产和应用提供参考。

Lithium sulfur battery has attracted extensive attention as highly promising next generation of rechargeable battery. However, lithium sulfur battery, especial the sulfur cathode, is still under experimental exploration, and the commercial carbon fiber felt is rarely reported to apply in the sulfur cathode. Herein, the flexible carbon-fiber- supported carbon-sulfur electrode was prepared, and its physical properties and electrochemical performance were characterized. The results showed that the interface resistance was reduced from 97.9 Ω to 22.6 Ω, due to porous three-dimensional network of the carbon fiber felt and micropore of the porous carbon which benefited energy density of the battery and conductivity of the sulfur cathode. Furthermore, the initial discharge capacity at 0.05C rate was 996.7 mAh/g and the discharge capacity at 2C rate after 140 cycles was 666.7 mAh/g when carbon fiber felt serves as current collector, while their counterparts with aluminum foil as the current collector were 772.9 and 471.6 mAh/g, respectively. Furthermore, the environmental-friend and low-cost binder LA132, super-P, and the ball-milling technique are beneficial to mass synthesis, suitable for the industrial production and the application of lithium sulfur battery.