Mesoporous nickel cobalt manganese sulfide yolk–shell hollow spheres for high-performance electrochemical energy storage

Abstract

Electrode materials with complex hollow architectures, large specific surface area, and porosity as well as more inner cavities are widely employed for high-performance supercapacitors. In the current work, we report a simple self-templating strategy to prepare a complex nickel cobalt manganese sulfide yolk–shell hollow sphere. Uniform nickel cobalt manganese glycerate solid spheres are first prepared as the template and subsequently transformed into nickel cobalt manganese sulfide yolk–shell hollow spheres by a sulfidation process. When utilized as electrode materials for electrochemical supercapacitors, the resultant nickel cobalt manganese sulfide yolk–shell hollow spheres exhibited a large specific capacitance of 1360 F g⁻¹ at 1.0 A g⁻¹ and superior rate capability. Furthermore, an asymmetric supercapacitor device was assembled using the nickel cobalt manganese sulfide yolk–shell hollow spheres and activated carbon. The device showed a high energy density of 49.8 W h kg⁻¹ at a power density of 1700 W kg⁻¹ and long-term cycling life (only 1.8% loss after 6000 cycles), suggesting their potential application in high-performance electrochemical energy storage.