One-step construction of FeNi LDH/FeNi2S4 heterojunctions for boosting electrocatalytic oxygen evolution reaction and hybrid capacitive storage

Construction of heterogeneous phases offers a promising strategy to tailor the physiochemical properties of electrode materials to improve their electrochemical performance toward energy conversion and capacitive storage. Herein, the hetero-phase combination of hexagonal FeNi layered double-hydroxide (FeNi-LDH) and spinel phase FeNi2S4 microsphere assembled with nanosheets is synthesized via one-step solvothermal process. Owing to improved components, unique micro-structures and the construction of heterogeneous engineering between FeNi LDH and FeNi2S4 with abundant active interface, FeNi LDH/FeNi2S4 heterojunctions exhibit an excellent electrochemical performance for oxygen evolution reaction (OER) and hybrid capacitive storage. The heterojunctions show low overpotential of 259 mV at 10 mA cm−2, small Tafel slope of 75 mV dec−1, excellent cyclic stability in OER, as well as an improved specific capacity of 472.5C g−1 at 1 A g−1 in hybrid capacitors. The preparation and dual-function applications of FeNi LDH/FeNi2S4 heterojunctions provide a new idea as the advanced electrode materials for electrocatalytic OER and hybrid capacitors.