A Novel Strategy of Multi-element Nanocomposite Synthesis for High Performance ZnO-CoSe2 Supercapacitor Material Development

Main observation and conclusion Developing multi-element composites is a promising way for high performance supercapacitor material development, and simplifying the synthesis steps is critical for reducing the preparation costs and successful promotion of the materials. A novel one-step selective reaction strategy is developed, and successfully used to prepare four-element ZnO-CoSe2 (ZOCS) nano-spherical composites, to be used as supercapacitor materials. Started form nano-spherical glycerate templates, under the optimal synthesis condition, the obtained ZOCS-0.125 electrode material exhibits a specific capacitance of 450.7 F/g at 1 A/g and a good rate performance by keeping 76.8% capacitance at 20 A/g. Moreover, the ZOCS-0.125 electrode exhibits excellent cycle stability of 114.9% capacitance retention after 5000 cycles at 10 A/g. An asymmetric supercapacitor assembled by ZOCS-0.125 and activated carbon electrodes delivers an energy density of 22.35 Wh/kg at 825 W/kg, and a cycle stability of 105.6% capacitance retention after 5000 cycles. This work not only shows the good potential of the facilely prepared ZnO-CoSe2 composite electrode material, but also demonstrates a new strategy for low cost and high performance multielement composite material development, that can be used in a wide range of applications.

Automated summary

The study introduces a novel one-step selective reaction strategy for the fabrication of ZnO-CoSe2 (ZOCS) nano-spherical composites as supercapacitor materials. These composites exhibit high specific capacitance, good rate performance, and excellent cycle stability, making them suitable for assembling asymmetric supercapacitors with superior energy density and cycle stability. This work not only demonstrates the potential of facilely prepared ZnO-CoSe2 composite electrode material, but also presents a new strategy for low-cost and high-performance multi-element composite material development.