Journal Article

Electrochemical Lithium Storage Performance of Molten Salt Derived V2SnC MAX Phase

Huang, Qing, Eklund Per, Hultman Lars, Li Youbing, Huang Zhengren, Lin Zifeng, Hou Jinrong, Du Shiyu, Shao, Hui, Jin, Na, Ma, Jiwei, Chen, Ke, Chai Zhifang, Zhang, Xiao, Liu, Ying, Xiao, Peng, Persson Per O Å, Ma, Guoliang, Xu, Jin, Lu, Jun, Li, Mian

2021

Overview

HighlightsSmall size V2SnC MAX phase was prepared by the molten salt method.V2SnC MAX phase electrode is able to deliver high gravimetric capacity up to 490 mAh g−1 and volumetric capacity of 570 mAh cm−3A charge storage mechanism with V2C-Li redox and Sn–Li alloying dual reactions was proposedMAX 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 V2SnC MAX phase by the molten salt method. V2SnC 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 V2SnC particles where Sn atoms are exposed to the electrolyte followed by a redox reaction that occurs at V2C 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.

• Publisher: Springer Nature B.V
• Subject: Alloying / Anodes / Density functional theory / Energy storage / Gravimetry / Lithium / Molten salts / Redox reactions