In-situ growth of hierarchical Ni–Co LDH/CoMoO4 nanosheets arrays on Ni foam for pseudocapacitors with robust cycle stability

Abstract

In this work, a nanoarray electrode composed of CoMoO4 nanosheets (CoMoO4 NSs) and Co–Ni layered double hydroxide (Ni–Co LDH) nanosheets supported on Ni foam (NF) is successfully constructed by an in-situ growth route. Firstly, cobalt molybdenum arrays were fabricated by a mild hydrothermal reaction as the core. Afterwards, the as-prepared electrode was utilized as a skeleton to immobilize Ni–Co LDH with an electrochemical deposition method. The electrochemical performance of the prepared Ni–Co LDH/CoMoO4/NF electrode, compared with CoMoO4/NF electrode, illustrated a high gravimetric specific capacitance (1812 F g−1 at 1 A g−1), excellent rate capability (68% at 50 A g−1), good cycle stability (93.7% capability retention after 5000 cycles) and the maximum energy density and power density of 62.92 Wh kg−1 and 12.5 kW kg−1, respectively. Moreover, an asymmetric supercapacitor (Ni–Co LDH/CoMoO4//AC) is fabricated with excellent electrochemical performance. The asymmetric supercapacitor with a maximum voltage of 1.6 V has demonstrated a high energy density of 79.28 Wh kg−1, a high power density of 11.97 kW kg−1 at 51.2 Wh kg−1 and outstanding cyclic stability with the capacitance retention of 93% after 5000 cycles. The increased pseudocapacitive behaviors are related to its unique core/shell structure which provides facilitated ion diffusion, rapid electron transport kinetics, and good strain accommodation that makes it a potential choice for electrochemical energy storage owing to the their considerable electrochemical properties.