CoS <sub>2</sub> Nanospheres Anchored on 3D N-Doped Carbon Skeleton Derived from Bacterial Cellulose for Lithium-Sulfur Batteries
Shuhui Wang, Jinze Guo, Ruisong Guo, Xiaohong Sun, Fuyun Li, Tingting Li, Xinqi Zhao, Yani Luo
Abstract
To address sluggish sulfur redox kinetic and the “shuttling behavior” of polysulfides in lithium-sulfur batteries (LSBs), CoS 2 hollow nanospheres tightly anchored on three-dimensional (3D) N-doped biological carbon nanofibers skeleton (CoS 2 /N-CNFs) are successfully designed as highly-efficient sulfur hosts. The carbon nanofibers obtained by carbonization of bacterial cellulose are interweaved with each other, and can provide a firm 3D conductive skeleton for the low-conductive sulfur cathode. And the N-doping carbon nanofibers skeleton with polar CoS 2 can achieve synergetic physical/chemical adsorption of polysulfides and effective catalytic conversion, which are contributed to enhance sulfur redox kinetic and effectively suppress the shuttling effect. Moreover, the skeleton with abundant −OH functional groups achieve strong chemisorption to CoS 2 , greatly maintaining structural stability during cycling process. Benefitting from the above-mentioned merits, CoS 2 /N-CNFs@S electrode with high sulfur loading of 74.4% exhibits superior reversible capacity of 497.3 mAh g −1 at 0.2 C after 100 cycles with an improved coulombic efficiency of approximately 100%, and the electrode has excellent cycle life with 73% capacity retention over 300 cycles at 0.5 C. This synthesis strategy makes a leading exploration for the application of biological carbon materials in advanced LSBs.