基于Co-N-C改性隔膜的高性能锂硫电池

High Performance Lithium-Sulfur Batteries Enabled by Co-N-C Modified Separators

设计制备了一种钴嵌入式叶片状氮掺杂碳(Co-N-C)材料改性隔膜用于锂硫电池,借助高分散单质钴提供的活性位点实现对正极侧中间产物多硫化物的化学锚定,抑制其溶解导致的穿梭效应;利用氮掺杂碳材料的微纳结构加快离子传输速率,提高电化学反应动力学,使改性隔膜实现吸附-催化协同作用。实验结果表明,采用此改性隔膜组装的锂硫电池,首圈比容量高达1408 mAh/g,且在1 C倍率下稳定循环400圈,衰减率仅为每圈0.05%,电池性能明显提升。

A leaf-like cobalt-embedded nitrogen-doped carbon material(Co-N-C)is successfully synthesized and then modified on the commercial separator for Li-S batteries.The Co nanoparticles are uniformly dispersed in the prepared Co-N-C.With a large surface area and amounts of micropores,Co-N-C materials provide more active sites to trap soluble polysulfides in the cathode and effectively inhibit the shuttle effect caused by the dissolution of polysulfides.Meanwhile,the micro-nano structure in N-doped carbon is beneficial to accelerate ion transport and enhance the redox reaction kinetics,Beneftting from the integrated adsorption-catalyzing effect,the Li-S cell constructed with a Co-N-C modified separator exhibits a high capacity of 1408 mAh/g and excellent cycling stability(a low capacity fading rate of 0.05%per cycle after 400 cycles at 1 C).