Deposition of Co_3O_4 films as High-Performance Supercapacitor Electrodes via the Solution Precursor Plasma Spray Route Place

摘要

In order to efficiently utilize emerging green energies, supercapacitors are receiving increasing attention as one of the most promising energy storage devices. The development of efficient and facile fabrication processes of highly active and stable metal oxide electrodes is therefore a key research area for the promotion of supercapacitors. In this work, we have directly deposited binder-free Co_3O_4 films featuring in-situ oxygen vacancies, using a novel rapid, one-step route, namely the Solution Precursor Plasma Spray (SPPS) process. The particle morphology of the synthesized Co_3O_4 films is sensitive to the spraying distance. In particular, Co_3O_4 films composed of hexagonal flakes were synthesized for the first time through the SPPS route. Specific capacitances up to 1700 F/g were obtained under a scan rate of 5 mV/s and up to 1276 F/g at a current density of 2 A/g. Moreover, the prepared Co_3O_4 films exhibited an excellent cycling stability with 96.9% retention of the capacitance (1156 F/g) after 13,000 cycles at a scan rate of 20 mV/s. The high performances of these Co_3O_4 electrode films as supercapacitors are ascribed to the synergistic effects of three original features, namely their bind-free feature, the existence of in-situ oxygen vacancies and their porous structures boasting optimized nanostructures. Furthermore, this work unveils the promising potential of the SPPS technique for the preparation of other binder-free, metal oxide films which could benefit from similar properties, namely oxygen vacancies and well-fitted nanostructures, and prove interesting not only as electrodes for supercapacitor but also in other energy storage applications.