Optimizing the fabrication of Co compounds coating on modified carbon cloth with enhanced pseudocapacitive performance and cyclic stability

With rapidly growing commercial markets of portable electronics, supercapacitors (SCs) have become one of the most promising energy storage devices due to their unique characteristics. However, the low energy densities severely restrict their practical application. Furthermore, the liquid-electrolyte has leak issues under deformation, resulting in device failure or performance degradation. Herein, a novel material which has a porous carbon (PC) nanostructure skeleton connected by tannic acid (TA) with Co metal compounds which can provide pseudocapacitance is designed. PC is derived by activation C₆₀ which is sp2 carbon that ensures the efficient transmission of electrons and Co metal compounds increase the active site of the Faraday redox reaction and improve the specific capacitance. TA makes porous carbon skeleton and Co metal compounds more closely linked, effectively improving ion transport efficiency and optimizing cycle performance. The composite showed a reversible specific capacity of 1475 mF cm⁻² at a charge/discharge current density of 2 mA cm⁻² and a specific capacity of 1174 mF cm⁻² at 30 mA cm⁻² when measured by a three-electrode system conducted in 2.0 M KOH electrolyte. In addition, the assembled solid-state symmetric SCs with the electrode materials have excellent cycling stability that cycled for 5000 cycles at 5 mA cm⁻² and the capacitance retention rate reached 95.76%. The device can also provide continuous and stable energy that lights up the red light-emitting diode (LED) with excellent bendability. This strategy provides a novel device design method and can be effectively applied to future flexible electronic products.