锂硫电池正极用钴掺杂空心多孔碳载体材料

锂硫电池被认为是新一代低成本、高能量密度的储能系统。但由于硫正极导电性差、穿梭效应严重以及氧化还原反应速率慢, 导致电池容量衰减严重, 倍率性能较差。本研究以柠檬酸钠为碳源制备了具有三维中空结构的多孔碳材料, 并在其骨架上负载钴纳米颗粒后作为硫正极的载体。引入的钴纳米颗粒可有效吸附多硫化物, 提升其转化反应的动力学, 进而明显改善电池的循环和倍率性能。所得的钴掺杂复合硫正极在0.5C (1C=1672 mAh·g^-1)的倍率下首圈放电比容量高达1280 mAh·g^-1, 在1C的倍率下稳定循环200圈后可保持770 mAh·g^-1, 并且具有优异的倍率性能, 即使在10C的大电流密度下仍可稳定循环。

Cobalt-doped Hollow Carbon Framework as Sulfur Host for the Cathode of Lithium Sulfur Battery

Lithium-sulfur batteries are deemed to be the next generation of cost-effective and high energy density systems for energy storage.However,low conductivity of active materials,shuttle effect and sluggish kinetics of redox reaction lead to serious capacity fading and poor rate performance.Herein,a sodium citrate derived three-dimensional hollow carbon framework embedded with cobalt nanoparticles is designed as the host for sulfur cathode.The introduced cobalt nanoparticles can effectively adsorb the polysulfides,enhance the kinetics of conversion reaction and further improve the cyclic and rate performance.The obtained cathode delivered a high initial discharge capacity of 1280 mAh·g^-1at 0.5C,excellent high-rate performance up to 10C and stable cyclic capacity of 770 mAh·g^-1at 1C for 200 cycles with high Columbic efficiency.