Oxygen-rich vacancies CuCoLDH with 1D/2D nanoarray structure for high performance asymmetric supercapacitor

Abstract

The performance of optimization layered double hydroxide (LDH) electrodes via oxygen vacancy engineering is of great significance for high-performance hybrid supercapacitors. Herein, we obtain oxygen-rich CuCoLDH (Ov-CuCoLDH) nanoarray structure by in-situ etching of Co-MOF nanorods and subsequent NaBH4 reduction. The addition of oxygen vacancy does not affect the original unique layered structure and creates more active centers, promoting faster electron transfer and ion conversion. Moreover, this method maximizes the synergistic effect between copper and cobalt ions. The as-assembled Ov-CuCoLDH electrode shows an outstanding specific capacity of 1392.4 F g−1. Furthermore, forming the Ov-CuCoLDH and AC electrodes possesses 58.2 W h kg−1 of energy density (at a power density of 850 W kg−1). At the end of 10,000 cycles, the CF@Ov-CuCoLDH//AC device keeps 86.7 % of the original capacitance, indicating a high degree of stability. The results show that the strategy of introducing oxygen vacancy by a mild and effective method to improve the capacity of LDH has a certain guiding significance for designing higher-performance electrode materials.