In-depth analysis of VARTM-based solid-state supercapacitors utilizing CNT-dispersed cobalt-bismuth-samarium ternary hydroxide on woven carbon fiber for enhanced energy storage

Abstract

Multi-metal hydroxides possess unique physical and chemical properties, making them promising candidates for supercapacitor working electrodes. Enhancing their electrochemical performance can be achieved through a combination with carbon materials. In this study, we synthesized a composite material by hydrothermally dispersed 4, 6, and 10 wt% carbon nanotubes (CNT) into ternary cobalt-bismuth-samarium hydroxide (CoBiSm-TOH). These nanocomposites were employed as the material for the working electrode in a supercapacitor. The findings reveal that at 1.5 A/g, the specific capacitance of CNT3@CoBiSm-TOH, using a three-electrode system, was found to be 852.91 F/g, higher than that of CoBi-BOH, CoBiSm-TOH, CNT1@CoBiSm-TOH and CNT5@CoBiSm-TOH—measuring 699.69, 750.34, 789.54 and 817.79 F/g, respectively. Moreover, CNT3@CoBiSm-TOH electrodes exhibited a capacitance retention of around 88% over 10,000 cycles. To demonstrate practical applicability, CNT3@CoBiSm-TOH was grown on woven carbon fiber (WCF), and a solid-state supercapacitor device was developed using the VARTM (vacuum-assisted resin transfer molding). This device displayed a specific capacitance of 272.67 F/g at 2.25 A/g. Notably, it achieved a maximum energy density of 53.01 Wh/kg at a power density of 750 W/kg and sustained excellent cycle stability over 50,000 cycles, maintaining 70% of its initial capacitance. These results underscore the importance of interfacial nanoengineering and provide crucial insights for the development of future energy storage devices.