Construction of layered micro-/nano-structured MoNiCo-S cathode and broad bean shell derived carbon anode for hybrid supercapacitors

Abstract

Transition metal sulfides, despite their abundance of electrochemically active sites, often demonstrate inadequate rate performance and mechanical stability. The development of a multi-dimensional hierarchical architecture has proven to be an effective approach to address the limitations associated with sulfides. In the present study, MoNiCo-S nanorods featuring hierarchical micro-/nano-structures were successfully synthesized through a straightforward methodology that involved “in situ growth-etching-vulcanization”. The one-dimensional nanostructure CoMoO₄ served as both the substrate and metal source for the in-situ growth of ZIF-67. Subsequently, Lewis acid was introduced to facilitate the formation of hydroxides, ultimately leading to the synthesis of sulfides via ion exchange with sulfur ions. Due to its rational design and element composition, MoNiCo-S exhibited excellent capacitance (3125.1 F/g at 1 A/g) and cycling stability (capacitance retention rate of 72.9 % over 5,000 cycles). In addition, the broad bean shell derived carbon (KBBC), prepared through a carbonization and activation process, demonstrated a specific capacitance of 295.0 F/g and a cyclic capacitance retention of 99.6 %. The assembled MoNiCo-S//KBBC asymmetric supercapacitor devices achieves a high energy density of 78.5 Wh kg⁻¹ at a power density of 1004.3 W kg⁻¹. After 10,000 cycles, the device exhibited a capacitance retention rate of 107.9 %, indicating excellent cycling stability. This research contributes significantly to the advancement of sulfide materials in the context of performance optimization design.