Electrochemical Lithium Storage Performance of Molten Salt Derived V2SnC MAX Phase
Youbing Li, Guoliang Ma, Hui Shao, Xiao Peng, Jun Lu, Jin Xu, Jinrong Hou, Ke Chen, Xiao Zhang, Mian Li, Per O. Å. Persson, Lars Hultman, Per Eklund, Shiyu Du, Zhifang Chai, Qing Huang, Na Jin, Jiwei Ma, Ying Liu, Zifeng Lin, Qing Huang
Abstract
Abstract MAX phases are gaining attention as precursors of two-dimensional MXenes that are intensively pursued in applications for electrochemical energy storage. Here, we report the preparation of V 2 SnC MAX phase by the molten salt method. V 2 SnC is investigated as a lithium storage anode, showing a high gravimetric capacity of 490 mAh g −1 and volumetric capacity of 570 mAh cm −3 as well as superior rate performance of 95 mAh g −1 (110 mAh cm −3 ) at 50 C, surpassing the ever-reported performance of MAX phase anodes. Supported by operando X-ray diffraction and density functional theory, a charge storage mechanism with dual redox reaction is proposed with a Sn–Li (de)alloying reaction that occurs at the edge sites of V 2 SnC particles where Sn atoms are exposed to the electrolyte followed by a redox reaction that occurs at V 2 C layers with Li. This study offers promise of using MAX phases with M-site and A-site elements that are redox active as high-rate lithium storage materials.