In-situ MOFs-derived hollow Co9S8 polyhedron welding on the top of MnCo2S4 nanoneedles for high performance hybrid supercapacitors

Abstract

MOFs-derived hollow Co 9 S 8 polyhedron welding on the top of MnCo 2 S 4 nanoneedles showed a superior energy density of 45.8 W·h·kg −1 at a power density of 800 W·kg −1 . • Waxberry-like MnCo 2 S 4 /Co 9 S 8 hierarchical electrodes are rationally constructed. • This unique structure provides more abundant reaction sites for faradaic reaction. • The MnCo 2 S 4 /Co 9 S 8 electrode exhibits a high specific capacity of 1100.5 F g −1 . • The assembled MnCo 2 S 4 /Co 9 S 8 //AC supercapacitor achieves an excellent electrochemical property. Metal-organic frameworks (MOFs) have been considered as the outstanding templates and precursors in synthesizing advanced cathode materials for supercapacitor. Herein, a novel hierarchical structure with hollow Co 9 S 8 polyhedrons welding on the top of MnCo 2 S 4 nanoneedles are rationally designed via a facile in-situ vulcanization approach. The unique morphology can provide more abundant reaction sites and ensure the efficient electron transport. Due to the synergistic effect between MnCo 2 S 4 and Co 9 S 8 , the hybrid electrode delivers a favorable specific capacity of 1100.5 F·g −1 at a current density of 1 A·g −1 in three-electrode system. Furthermore, an assembled asymmetric supercapacitor comprising MnCo 2 S 4 /Co 9 S 8 and activated carbon delivers a high energy density up to 45.8 W·h·kg −1 at a power density of 800 W·kg −1 . Moreover, the device holds more than 94.8% capacitance retention after 5000 cycles, demonstrating it could be a potential electroactive material for next-generation high performance energy storage device.