Binary cooperative NiCo2O4 on the nickel foams with quasi-two-dimensional precursors: a bridge between ‘supercapacitor’ and ‘battery’ in electrochemical energy storage

Abstract

Some inorganic quasi-two-dimensional nanomaterials such as cobalt–nickel hydroxides are kinetically facile for a capacitive charge storage process. However, high performance capacitive charge storage needs a balance of the ionic and electronic transporting, and to build up an integrated architecture on substrates step by step and utilize the interface better is still a key challenge. As the interfacial assembly has conflicted with our goals for high-performance capacitive charge storage process, we identify theoretically and experimentally binary cooperative nanoscale interfacial materials to solve the problem. Co–Ni-hydroxide precursors were prepared by hybrid quasi-two-dimensional nanosheets and hetero-oriented nanocrystallines walls. Followed by dip-dry and annealing, NiCo₂O₄ could adhere to the nickel foams robustly with a solution-based surface treatment. Moreover, an unusual phenomenon in the electrochemical test inspired us to establish a bridge between ‘supercapacitor’ and ‘battery’. The bridged gap highlights a new design idea for high-performance energy storage.