MIL-88-derived porous carbon rod-supported FePS3 nanosheet arrays for robust sodium storage

Abstract

Ternary metal phosphorus trisulfide (MPS3) has emerged as an excellent candidate for use as an anode in sodium-ion batteries, characterized by its unique layered structure, easily tunable physicochemical properties, and high theoretical capacity. However, its intrinsic challenges such as low electrical conductivity and susceptibility to fragmentation have led to unsatisfactory rate and cyclic capability. Herein, the intriguing microcomposite structure of porous carbon rod-supported FePS3 nanosheet arrays (FePS3@CR) is ingeniously constructed in situ via the phospho‑sulfurization of MIL-88. FePS3@CR showcases multiple structural advantages, including enhanced electrical conductivity, increased surface area, accelerated electron transfer rate, and mitigated structural stress. These combined benefits endow FePS3@CR with improved rate capability (808.0 and 474.3 mAh g−1 at 0.1 and 10 A g−1, respectively) and cyclic life (94.5 % retention after 1500 loops at 2 A g−1). The assembled full battery also demonstrates robust cycling stability, retaining 94.2 % of its capacity after 1100 loops at 0.5 A g−1. The specific sodium storage process of the FePS3 electrode is investigated through ex-situ structure analysis. This work presents innovative structural designs potentially improving the energy storage performance of MPS3 material system.