Design and simple preparation of a novel 1D/2D/3D multi-structure composite for high-performance supercapacitors

In this paper, a novel NiCoCr-LDH/NiCoO2@NF (1D/2D/3D) composite are developed for supercapacitor. In the composite, one dimensional (1D) Cr-doped NiCoCr-LDH provided more active sites and facilitated redox reaction by modulating the valences of alloy elements. The enhanced cycle stability and conductivity were obtained due to the low electronegativity of two-dimensional (2D) NiCoO2 while high porosity and stability were achieved by the three-dimensional structure of (3D) Ni foam. Furthermore, heterointerface formed by LDH, metal oxides and Ni foam in the composite provided efficient methods to improve conductivity and stability of active electrode materials. Thanks to the above advantages, the NiCoCr-LDH/NiCoO2@NF composite exhibits remarkable performance as the anode of supercapacitor. The as-fabricated electrode using NiCoCr-LDH/NiCoO2@NF composites exhibits excellent area specific capacitance of 2.481 F cm-2 at 1 mA cm-2, which reaches about 3 times as much as traditional NiCo-LDH, and good capacitance retention of 67.3% after 5000 cycles at 10 mA cm-2. Also, a NiCoCr-LDH/NiCoO2@NF//AC asymmetric supercapacitor has a high energy density of 0.214 mWh cm-2 at a power density of 0.774 mW cm-2, and showed good capacity retention of 54.39% after 5000 cycles at 10 mA cm-2. This study reports a strategy to fabricate excellent battery-type electrode materials of supercapacitors via LDH composites design.