3D nitrogen and sulfur equilibrium co-doping hollow carbon nanosheets as Na-ion battery anode with ultralong cycle life and superior rate capability

• DOI: 10.1016/j.apsusc.2021.149168
• Publication Date: 2021-01-30T11:53:41Z
• Authors: Lu Yue; Wanyin Xu; Kai Li; Liwei Xiao; Chengjie Feng; Xinyang Si; Kun Cheng; Feng Zhang; Guihua Hou; Wenhui Zhang
• Keywords: Carbon fibers; Sodium-ion battery; Heteroatom

Abstract In sodium ion batteries, heteroatom doping is deemed to be an important way to enhance the electrochemical activity of carbon-based anode materials. In this work, we report 3D nitrogen and sulfur equilibrium co-doping hollow carbon nanosheets for sodium ion battery anode, which can deliver a maximum capacity of 497 mA h g−1 under 0.2 A g−1, good rate capability (260 mA h g−1 under 50 A g−1 and 245 mA h g−1 under 60 A g−1), and good cycling stability (339 mA h g−1 under 5 A g−1 over 5000 cycling and 249 mA h g−1 under 10 A g−1 over 5000 cycling), suggesting wonderful electrochemical performance. To the best of our knowledge, the excellent performance of the long-term cyclability at such high rates is rarely reported for carbon-based sodium ion battery anodes. Meanwhile, the storage mechanism of sodium was studied by in-situ Raman spectroscopy, cyclic/linear sweep voltammetry and electrochemical impedance spectroscopy. Its superior properties can be attributed to the special three-dimensional hollow nanosheets with high specific surface, doping regulation of N and S elements to carbon structure and synergistic effect of nitrogen doping enhancing pseudocapacitive contributions.