Bhardwaj Ravindra Kumar, Jayanthi Swetha, Adarakatti Prashanth Shivappa, Sood A K, Bhattacharyya Aninda J
Solid State and Structural Chemistry Unit, Indian Institute of Science, Bengaluru 560012, India.
Department of Physics, Indian Institute of Science, Bengaluru 560012, India.
ACS Appl Mater Interfaces. 2020 Jun 24;12(25):28120-28128. doi: 10.1021/acsami.0c04507. Epub 2020 Jun 10.
The extent of confinement of soluble metal polysulfides inside a sulfur cathode strongly determines the performance of metal-sulfur rechargeable batteries. This challenge has been largely tackled by loading sulfur inside various conducting porous scaffolds. However, this approach has not proven to be fully effective because of poor chemical interaction between the scaffold and polysulfides. Here, we demonstrate an excellent strategy of using a sulfide additive in the sulfur cathode, ., cobalt nickel sulfide (CoNiS), to efficiently trap the soluble polysulfides inside the sulfur cathode. Raman and UV-vis spectroscopies clearly reveal higher retention of polysulfides inside CoNiS/S compared to bare sulfur and carbon-sulfur mixture cathodes. Against sodium, the CoNiS/S assembly showed remarkable cyclability both as a function of current density (at room temperature) and temperature (at constant current density). The versatility of CoNiS is further proven by the exemplary cyclability at various current densities at room temperature against lithium.
可溶性金属多硫化物在硫阴极内的受限程度在很大程度上决定了金属硫可充电电池的性能。通过将硫负载在各种导电多孔支架内，这一挑战已在很大程度上得到解决。然而，由于支架与多硫化物之间的化学相互作用较差，这种方法尚未被证明是完全有效的。在这里，我们展示了一种在硫阴极中使用硫化物添加剂（即钴镍硫化物（CoNiS））的出色策略，以有效地将可溶性多硫化物捕获在硫阴极内。拉曼光谱和紫外可见光谱清楚地表明，与裸硫和碳硫混合阴极相比，CoNiS/S内的多硫化物保留率更高。对于钠，CoNiS/S组件在作为电流密度（在室温下）和温度（在恒定电流密度下）函数时均表现出显著的循环稳定性。CoNiS在室温下针对锂在各种电流密度下的示例性循环稳定性进一步证明了其通用性。
