Synthesis and sodium storage performance of MxSy@N, C composites derived from l-methionine-based MOFs

Transition metal sulfides (TMSs), celebrated for their elevated theoretical capacities, are prospective anode candidates for sodium-ion batteries (SIBs). However, the conventional synthesis of TMSs is marred by intricate, multi-stage procedures and reliance on external sulfur precursors. Herein, we present a novel one-pot synthesis strategy utilizing l-methionine within a metal–organic framework (MOF) to incorporate carbon, nitrogen, and sulfur sources, thereby enabling the direct synthesis of carbon, nitrogen-doped sulfides (M_xS_y@N, C) without the need for external sulfurization agents. By altering the metal ions, we synthesized a series of M_xS_y@N, C composites characterized by co-doping with nitrogen and carbon. Among these, Co₉S₈@N, C demonstrated an impressive reversible sodium ion capacity of 592.7 mAh/g at a current density of 200 mA/g, along with stable cycling performance over 150 cycles and superior rate capability. These findings underscore the potential of this material as a high-performance anode for SIBs. Our research signifies a significant advancement in the synthesis of transition metal sulfides for energy storage applications, laying the groundwork for the development of high-capacity, long-lasting anode materials. This work contributes to the progress of energy storage technologies and supports the expansion of SIBs.