Construction of binder-free 3-D porous NiMn LDH electrode materials for high performance asymmetric supercapacitors using dynamic hydrogen bubbles as template

Three-dimensional porous Ni/NiMn layered double hydroxides (3-D Ni/NiMn LDH) with enhanced specific capacitance and superior cycle stability were loaded on nickel foam (NNM/NF) by combining dynamic hydrogen bubble template (DHBT) and electrodeposition methods. The optimized NNM-2/NF electrode for supercapacitors (SCs) possessed high specific capacitance (2755.36 F g–1 at 1 A g–1) and considerable capacitance retention (71.25% after 5000 consecutive cycles at 20 A g–1). When NNM-2/NF and active carbon (AC) were used to construct an asymmetric supercapacitor (ASC) device, it achieves a high specific energy density of 41.75 Wh kg–1 at a power density of 2700.09 W kg–1 and an excellent cycling performance (109.85% capacitance retention after 5000 cycles at 20 A g–1). The practical energy storage applicability of this device was demonstrated by the lighting of an LED bulb when two NNM-2/NF//AC devices were connected in series. This work provided potential strategy to promote the further application of porous Ni/NiMn LDH electrodes in new-generation energy storage.