Carbon‐Coated MOF‐Derived Porous SnPS₃ Core–Shell Structure as Superior Anode for Sodium‐Ion Batteries

Abstract

Metal thiophosphites have recently emerged as a hot electrode material system for sodium‐ion batteries because of their large theoretical capacity. Nevertheless, the sluggish electrochemical reaction kinetics and drastic volume expansion induced by the low conductivity and inherent conversion‐alloying reaction mechanism, require urgent resolution. Herein, a distinctive porous core–shell structure, denoted as SnPS3@C, is controllably synthesized by synchronously phosphor‐sulfurizing resorcinol‐formaldehyde‐coated tin metal–organic framework cubes. Thanks to the 3D porous structure, the ion diffusion kinetics are accelerated. In addition, SnPS3@C features a tough protective carbon layer, which improves the electrochemical activity and reduces the polarization. As expected, the as‐prepared SnPS3@C electrode exhibits superior electrochemical performance compared to pure SnPS3, including excellent rate capability (1342.4 and 731.1 mAh g−1 at 0.1 and 4 A g−1, respectively), and impressive long‐term cycling stability (97.9% capacity retention after 1000 cycles at 1 A g−1). Moreover, the sodium storage mechanism is thoroughly studied by in‐situ and ex‐situ characterizations. This work offers an innovative approach to enhance the energy storage performance of metal thiophosphite materials through meticulous structural design, including the introduction of porous characteristics and core–shell structures.