Hollow Co3O4 nanoparticles on CNF with polydopamine assistance for enhanced supercapacitor electrodes

Transition metal oxides (TMOs) are increasingly recognized as viable cathode materials for pseudocapacitors, due to their substantial theoretical capacity, widespread availability, and environmental benignity. However, their practical application is hindered by significant volumetric expansion during reactions and their inherently limited electrical conductivity. The design of hollow nanoarchitectures, coupled with carbonaceous material integration, has emerged as a potent approach to surmount these limitations. Herein, we reported a stepwise synthesis method where Cobalt oxide (Co3O4) nanoparticles, anchored onto carbon nanofibers (CNF) pre-modified with Polydopamine (PDA) known for its superior adhesion, were transformed into HCo3O4@C@CNF composite materials via a high-temperature annealing process. The mass ratio of Co3O4 to CNF was optimized, with a 3:1 ratio being identified as ideal. This optimized HCo3O4@C@CNF electrode exhibited outstanding electrochemical performance, attaining a significant specific capacitance of 2992 F g(-1) at 3 A g(-1) and maintaining a 91% capacitance retention rate following 8000 charge-discharge cycles. The CNF acted as an efficient conductive network, substantially enhancing the electrical conductance. Furthermore, the incorporation of PDA facilitated a more uniform dispersion and substantial loading of Co3O4, while the carbon shell, formed upon carbonization, effectively prevented the agglomeration of HCo3O4 nanoparticles, enhancing the overall stability and performance of the electrode. Therefore, the synthesized HCo3O4@C@CNF electrodes exhibit a viable approach for the preparation of electrode materials with high-performance.