Synthesis of hierarchical porous Co(OH)2/Ni2Mn1Ox composites on Ni foam for high performance battery-supercapacitor hybrid devices

In this work, nickel-manganese metal oxide (NiMnOx) composites with different Ni to Mn molar ratios onto Ni foam (NF) were fabricated by one-pot hydrothermal method. The influence of Ni to Mn molar ratio on the electrochemical performance was investigated and the optimal value was determined to be 2/1 (Ni2Mn1Ox/NF). A Co(OH)2/Ni2Mn1Ox/NF nanocomposite with novel porous honeycomb network structure was designed by electrodeposition Co(OH)2 on the surface of Ni2Mn1Ox/NF. The specific capacity value of Co(OH)2/Ni2Mn1Ox/NF composite electrode material reaches 949.02 C g−1 at 1 A g−1, which is obviously superior to those of the Ni2Mn1Ox/NF electrode. A battery-supercapacitor hybrid (BSH) device was assembeld by developing Co(OH)2/Ni2Mn1Ox/NF with activated carbon (AC), which possesses a promising energy of 47.34 Wh kg−1 at 424.69 W kg−1 power density, cycling retention 100% even after 5000 cycles over a voltage window of up to 1.7 V. This approach generates a strategy to fabricate nanocomposite electrode materials and also provides a promising contender for battery-supercapacitor hybrid devices in energy storage.