Dual Functions of Potassium Antimony(III)‐Tartrate in Tuning Antimony/Carbon Composites for Long‐Life Na‐Ion Batteries

Abstract Antimony holds a high‐specific capacity as a promising anode material for Na‐ion batteries (SIBs) and much research is focused on solving the poor cycling stability issue associated with its large volume expansion during alloying/dealloying processes. Here, self‐thermal‐reduction method is successfully applied to prepare antimony/carbon rods (Sb/C rods) utilizing potassium antimony(III)‐tartrate (C 8 H 10 O 15 Sb 2 K 2 ) as a dual source of carbon matrix and metallic antimony. According to theory calculations and experiment results, the formation process is explicitly explored as follows: C 8 H 10 O 15 Sb 2 K 2 → Sb 2 O 3 /C → Sb 2 O 3 /Sb/C → Sb/C rods. Notably, organic ligands in C 8 H 10 O 15 Sb 2 K 2 can be gradually turned into amorphous carbon with simultaneous reduction of Sb 3+ to metal Sb. Moreover, potassium chloride acts as an activator and a template during the course of carbonization, and synchronous reduction is introduced. Consequently, an antimony/carbon electrode material denoted as SbOC/C is formed, exhibiting a unique dual‐carbon‐modified structure and extensive SbOC bridge bonds that give rise to outstanding cycling performance and rate capacity. Specifically, the capacity is maintained at 404 mA h g −1 with 89% retention after 700 cycles at 500 mA g −1 . The low‐cost, self‐thermal‐reduction method and excellent electrode performances of electrode material make it attractive for large‐scale energy storage systems.