In Situ Universal Construction of Thiophosphite/MXene Hybrids via Lewis Acidic Etching for Superior Sodium Storage

Abstract

AbstractMetal thiophosphite has demonstrated promising application potential as an anode material for sodium‐ion batteries. Nevertheless, the intrinsic low electrical conductivity and drastic volume expansion impede its commercialization. Herein, a series of metal thiophosphite/Ti3C2Tx (metal = Fe, Ni, Co, and Cd) composites are constructed via Lewis acidic molten salt etching followed by synchronous phospho‐sulfurization. The Ti3C2Tx substrate endows the thiophosphite/Ti3C2Tx hybrids with high electrical conductivity. Importantly, thiophosphite grown on the MXene layers exhibits a 3D cross‐linked structure, which not only facilitates electron/ion transport, but also maintains robust structural stability owing to the space confinement effect. As a proof of concept, FePS3/Ti3C2Tx demonstrates remarkable rate performance (827.4 and 598.1 mAh g−1 at 0.1 and 10 A g−1, respectively) along with long‐term cycling stability (capacity retention of 93.7% after 2000 cycles at 5 A g−1). Impressively, the FePS3/Ti3C2Tx//NVPO full cell exhibits a high reversible capacity of 396.8 mAh g−1 over 1350 cycles at 2 A g−1. The sodium storage mechanism of FePS3/Ti3C2Tx anode is further unveiled through in situ XRD/ex situ HRTEM characterizations and theoretical calculations. This work provides a fresh perspective on enhancing the electrochemical performance of thiophosphite through the in situ construction of thiophosphite/Ti3C2Tx hybrids.