Hierarchical MnCo-LDH/rGO@NiCo2S4 heterostructures on Ni foam with enhanced electrochemical properties for battery-supercapacitors

Abstract

The rational construction and synthesis of mixed composites made up of multiple components as electrode materials have shown great potential in battery-supercapacitors. Here, the hybrid structure of MnCo-layered double hydroxide onto reduced graphene oxide (MC-LDH/rGO) and NiCo2S4 (NCS) is prepared via a two-step method. The electrochemical performance of the composites were optimized systematically by the growth/deposition cycles of the NCS material. When the deposition cycle reaches 6 (MC-LDH/rGO@NCS-6), the prepared composite exhibits the superior electrochemical performance due to the compositional and structural advantages. The resulting MC-LDH/rGO@NCS-6 composite achieves an excellent specific capacity (1446.5C g−1 at 1 A g−1) and the outstanding cycling life (98% capacity retention after 5000 cycles at 10 A g−1). Besides, a battery-supercapacitor hybrid device based on MC-LDH/rGO@NCS-6 composite and active carbon electrode possesses a remarkable energy density of 55.8 Wh kg−1 at a power density of 856.2 W kg−1 and a better cycling performance (100% capacity retention after 6000 cycles at 10 A g−1), suggesting the promising candidates of MC-LDH/rGO@NCS composites for high-performance battery-supercapacitors.