Upgrading a Supercapacitor by Particalizing Each Ultrathin Nanosheet into a Grain-Bearing Jigsaw-Like Layer

• Published in: Energy & fuels Vol. 36; no. 13; pp. 7096 - 7103
• Main Authors: Hu, Shuna, Liu, Fang, Huang, Qingsong
• Format: Journal Article
• Language: English
• Published: American Chemical Society 07.07.2022
• Subjects: Batteries and Energy Storage
• ISSN: 0887-0624; 1520-5029
• DOI: 10.1021/acs.energyfuels.2c00906

Transition metal compounds are usually adopted as electrode materials for supercapacitors. The obtained amorphous Co­(CO3)0.5(OH)·0.11H2O (CoCH) electrode nanosheet before calcination can achieve a specific capacity of 691.6 C/g, at a current density of 1 A/g, as well as an excellent rate performance 30.88% from 1 to 20 A/g. Particalization of electrode CoCH nanosheets into crystal nanograins can boost the supercapacity from 691.6 to 1308 C/g remarkably. Furthermore, if obtained CoCH grains can be transferred to a new phase with higher capacity, the performance should be enhanced even better, in theory. However, with CoCH transforming into Co3O4 nanoparticles gradually, the supercapacity rises first and falls after reaching a peak point, which might be arising from the magnetic proximity effect (MPE) of Co3O4 nanoparticles. The supercapacitor performance should be weakened by the Co3O4 crystal grain increment in density, so that an optimal property can be achieved near the peak point, for example, a power density of 967 W kg–1 at an energy density of 35.3 Wh kg–1 and 8.62 W kg–1 at 16251.3 Wh kg–1. The result indicates that MPE should exhibit an important influence on energy storage if the grain layout can be adjusted into a suitable magnetic response configuration.