Abstract:With the rapid development of renewable energy and portable electronic devices, the development of new energy storage materials with high energy density, high power density, and long cycle life is the key to breaking through the current bottlenecks in energy storage technology. In response to the issues of low electronic conductivity and insufficient cycling stability of the single ZnCo?O? electrode material, this study aimed to construct a heterostructure by introducing V?O?. Using a two-step hydrothermal method-in situ growth process, a ZnCo?O?/V?O? heterostructure nanosheet array was successfully fabricated on the foam nickel substrate, and systematic electrochemical tests and cycling stability tests were conducted on it. The following main conclusions were drawn. This composite material exhibits a double redox peak, and the analysis of the storage mechanism shows that the b value ranges from 0.82 to 0.84, indicating a mixed storage mechanism dominated by surface capacitance behavior. The charge transfer resistance is as low as 0.80 Ω, demonstrating excellent reaction kinetics characteristics. The composite material has a specific capacity of 850 C·g?1 at a current density of 1 A·g?1, a capacity retention rate of 70.6% at a high current density of 10 A·g?1, a capacity retention rate of 91.7% after 1 000 cycles at 5 A·g?1, and an energy density retention rate of 89.6%. The comprehensive electrochemical performance of this composite material is significantly superior to that of pure ZnCo?O? and pure V?O? electrodes. The tight hetero-interface of this material belongs to an in situ growth without binder construction, which optimizes the electron transmission path and shortens the ion diffusion distance, and collaboratively achieves a unified high specific capacity, excellent rate performance, and long cycling stability. This provides a new idea for the development of high-performance supercapacitor electrode materials. The long-term cycling stability test results show that after 1 000 cycles at a high current density of 5 A·g?1, the specific capacity of the ZnCo?O?/V?O? electrode stabilizes at 660.0 C·g?1 from the initial 720.0 C·g?1, with a capacity retention rate of 91.7%, an energy density retention rate of 89.6%, and a power density retention rate of 97.8%, which is significantly better than that of pure ZnCo?O? and pure V?O? electrodes. The ZnCo?O?/V?O? composite material prepared in this study not only provides a high initial capacity but also exhibits slow capacity decay, good reversibility, and stable performance during long-term cycling, and has good market application potential. Further research is needed to characterize and analyze the microscopic morphology, element distribution, and structural evolution after cycling of this material, in order to further reveal the fine structure and stability mechanism of the hetero-interface.
