In situ growth of glucose-intercalated LDHs on NiCo2S4 hollow nanospheres to enhance energy storage capacity for hybrid supercapacitors

Abstract

Layer double hydroxides (LDHs) have been considered ideal material for energy storage owing to their high theoretical capacity. However, the narrow layer spacing of LDHs affects the diffusion of electrolyte ions and the exposure of active atoms. In addition, intrinsic flaws such as low conductivity and poor cycle still restrict the practical application of LDHs. It is urgent to apply modification strategies to effectively activate intrinsic energy storage performance of LDHs. In this work, we designed glucose-intercalated LDHs on the surface of NiCo2S4 hollow nanospheres by in situ growth strategy to prepare NiCo2S4 @NiCo-G-LDH materials. The glucose-intercalated LDHs showed an appropriate layer spacing of 8.9 Å, which minimized the diffusion path of electrolyte ions and accelerated the kinetics of redox reactions. Besides, the introduction of transition metal sulfides (TMSs) has effectively improved the electrical conductivity of the LDHs, thus showing excellent electrochemical performance. Examined as the supercapacitor electrode; the as-prepared NiCo2S4 @NiCo-G-LDH material possesses an ultrahigh specific capacity of 986 C g−1 at 1 A g−1 and a rate capability of 73.1% even at 30 A g−1. Furthermore, the fabricated hybrid supercapacitor device using NiCo2S4 @NiCo-G-LDH as the positive electrode and commercial activated carbon as the negative electrode achieved a competitive energy density of 54.5 Wh kg−1 at a power density of 400.0 W kg−1 and preeminent cycle stability of 88.9% over 10000 cycles.