Facile synthesis of Ni3Se4/Ni0.6Zn0.4O/ZnO nanoparticle as high-performance electrode materials for electrochemical energy storage device

To enhance the performance of transition metal chalcogenide composite electrode material, a key point is a composite design and preparation based on the synergistic effect between the oxide and selenide materials. With a facile 'one step template-annealing' step, Ni3Se4, Ni0.6Zn0.4O and ZnO are simultaneously synthesized, by 500 degrees C annealing. With the increase of annealing temperature from 350 degrees C to 600 degrees C, nickel selenides change from NiSe2 to Ni3Se4 to NiSe. The charge storage capacity increases first and then decreases with the increase of annealing temperature, and the 500 degrees C annealing obtained three compound composite Ni3Se4/Ni0.6Zn0.4O/ZnO (NNZ-500) nanoparticle material displayed a high specific capacitance of 1089.2 F g(-1) at 1 A g(-1), and excellent cycle stability of 99.8% capacitance retention after 2000 cycles at 5 A g(-1). Moreover, an asymmetric supercapacitor was assembled with NNZ-500 as the positive electrode material and activated carbon as the negative electrode material. This kind of asymmetric supercapacitor demonstrated a high energy density of 53.4 Wh kg(-1) at 819.0 W kg(-1), and cycle stability with 98.6% capacitance retention after 2000 cycles. This material preparation approach provides great potential for the future development of high performance transition metal composite electrode materials in energy storage applications.