Interleaved Nanosheet Mxene@Czts Heterostructure with Reversible and Stable Capacity for Sodium-Ion Batteries

Abstract

Ti3C2Tx MXene, an emerging two-dimensional material, has garnered considerable attention as a promising material for sodium-ion batteries due to its excellent electrical conductivity, abundant surface functional groups, and unique layered structure. Often combined with other materials to construct heterostructures because of its relatively low theoretical capacity, metal sulfides, when subjected to highly selective and controllable multi-cation co-doping, can exploit the synergistic effects among different functional dopant atoms, achieving high charge storage, robust crystal structure, and superior sodium ion reaction kinetics simultaneously. In this study, monolayer Ti3C2Tx MXene nanosheets were obtained through etching and centrifugation, followed by the in-situ growth of Sn-Zn co-doped Cu2ZnSnS4 (CZTS) nanosheets via a simple hydrothermal reaction. The prepared MXene@CZTS heterostructure leverages the beneficial properties of each component, significantly enhancing the material's sodium ion storage capability. As a result, the MXene@CZTS anode material exhibits a specific capacity of 475.7 mAh g-1 at a current density of 0.2 A g-1 and maintains a reversible capacity of 332 mAh g-1 after 1000 cycles at 2 A g-1, with a coulombic efficiency nearly reaching 100%, demonstrating outstanding sodium storage performance and stable reversible capacity. These excellent sodium storage characteristics make the material a strong candidate for sodium-ion battery anode materials.

Keywords: MXene, interleaved nanosheet structure, CZTS, Anode, Sodium-ion batteries