Engineering New Hybrid Structure of Nife2o4@Nico2o4 Hollow Algae Microspheres Enabled by Mott-Schottky Heterojunction Towards Advanced Electrochemical Performance

Designing hybrid structure of transition metal oxides (TMOs) with controlled morphology can adjust the electronic structure and create more kinetics reactions. Herein, a new kind of NiFe2O4@NiCo2O4 nanocomposite was synthesized with one pot-hydrothermal. The unique hollow algae microspheres with plenty nanowires and the synergistic effect factors promote high electroactive sites and generate a built-in electric field. The constituted Mott-Schottky heterostructure creates strong interfacial interaction, paves the way for the electrolyte ions diffusion and results high charges transfer abilities by reducing the energy barriers in the heterointerface. As cathode material, the NiFe2O4@NiCo2O4 presents satisfactory capacitance of 2013 F.g-1(253.8 mAh.g-1) at 0.5 A·g-1), and maintains ultrahigh capacitance retention of 80% at 30 A·g-1 with marvellous stability of only 7% loss during 20,000 cycles. Interestingly, asymmetric hybrid supercapacitor device based NiFe2O4@NiCo2O4 provides tremendous energy density of 93.6 Wh·kg-1 at 350 W·kg-1 power density. What's more, all-solid-state device offers ultra-low self-discharge of 9.5% through 24 h. Therefore, the combination of NiFe2O4@NiCo2O4 to form Mott-Schottky heterojunction was a promising strategy to develop electrode material with high energy storage performance.