Ren Naiqing, Wang Lifeng, He Xiaodong, Zhang Liming, Dong Jiemin, Chen Fei, Xiao Jingchao, Pan Bicai, Chen Chunhua
CAS Key Laboratory of Materials for Energy Conversion, Department of Materials Science and Engineering & Collaborative Innovation Center of Suzhou Nano Science and Technology, University of Science and Technology of China, Hefei, Anhui 230026, China.
Hefei National Laboratory for Physical Sciences at the Micro scale, Key Laboratory of Strongly-Coupled Quantum Matter Physics, Department of Physics, University of Science and Technology of China, Hefei, Anhui 230026, China.
ACS Appl Mater Interfaces. 2021 Oct 6;13(39):46813-46820. doi: 10.1021/acsami.1c14935. Epub 2021 Sep 21.
Hard carbons (HC) derived from biomass material are most promising anodes for lithium-ion batteries (LIBs) because of their cost effectiveness and environmental friendliness. However, the low initial Coulombic efficiency (ICE) of HC anodes reduces the energy density of full cells, which seriously impedes their practical applications. Herein, we demonstrate that the ICE of HC anodes can be significantly improved by modulating the work function of a model HC derived from cotton and deliberately treated to form C-Cl bonds on its surface. By X-ray absorption near-edge structure and density functional theory (DFT) calculation studies, it is verified that the introduction of the C-Cl bond leads to the electron transfer from C to Cl and enhances the work function of the system. In addition, this Cl-doped HC anode can inhibit the reduction of solvent molecules in the electrolyte and reduce the formation of a solid electrolyte interface (SEI) film. Consequently, the ICE is improved from 64.8 to 78.1%. This study provides an effective route to reduce the formation of the SEI film and improve the ICE of hard carbon anodes for LIBs.
源自生物质材料的硬碳（HC）因其成本效益和环境友好性，是锂离子电池（LIBs）最具潜力的阳极材料。然而，HC阳极较低的初始库仑效率（ICE）降低了全电池的能量密度，严重阻碍了其实际应用。在此，我们证明，通过调节一种源自棉花并经特殊处理使其表面形成C-Cl键的模型HC的功函数，HC阳极的ICE可得到显著提高。通过X射线吸收近边结构和密度泛函理论（DFT）计算研究，证实了C-Cl键的引入导致电子从C转移至Cl，并增强了体系的功函数。此外，这种Cl掺杂的HC阳极可抑制电解质中溶剂分子的还原，并减少固体电解质界面（SEI）膜的形成。因此，ICE从64.8%提高到了78.1%。本研究提供了一条有效途径，可减少SEI膜的形成并提高LIBs硬碳阳极的ICE。
