3D hierarchical core–shell structural NiCoMoS@NiCoAl hydrotalcite for high-performance supercapacitors

Abstract

A 3D heterogeneous hierarchical core–shell NiCoMoS@NiCoAl hydrotalcite (NiCoMoS@LDH) electrode material was prepared by growing ultrathin NiCoAl-LDH nanosheets onto NiCoMoS nanoneedles arrayed on Ni foam (NF). After coating NiCoAl-LDH on the NiCoMoS array, the strong interaction of the two constituents could mediate the surface electronic structure to improve interfacial charge transport and offer more available active sites for the faradaic reaction. The optimized NiCoMoS_2/1@LDH material showed a high specific charge of 1336.0 C g⁻¹ at 1.0 A g⁻¹, superior to that of the pristine NiCoAl-LDH and NiCoMoS directly grown on NF. Furthermore, an asymmetric supercapacitor was assembled with NiCoMoS_2/1@LDH as the cathode and active carbon (AC) as the anode, which afforded a high energy density of 41.9 W h kg⁻¹ at a power density of 800 W kg⁻¹. And the device showed excellent cycling performance (89.3% retention after 10 000 cycles), revealing that NiCoMoS_2/1@LDH had potential application as the electrode material in high-performance energy storage.