Flexible and porous Co3O4-carbon nanofibers as binder-free electrodes for supercapacitors

Herein, flexible and porous Co3O4-carbon nanofibers (Co3O4-CNFs) were fabricated by electrospinning technique combining with the followed carbonization process. The effects of material composition and calcination temperature on morphology, pore structure, and electrochemical properties of the Co3O4-CNFs were systematically investigated. Results indicated that the obtained Co3O4-CNFs exhibited high porosity, high mechanical strength, and superior electrical conductivity. Electrochemical characterization results showed that the optimized Co3O4-CNFs as binder-free electrodes exhibited a specific capacitance of 369 F g(-1) at the current density of 0.1 A g(-1). Even at a high current density of 2 A g(-1), the specific capacitance still remained at 181 F g(-1), with the capacitance retention rate of 49%. Intriguingly, the prepared Co3O4-CNF film could recover to its original state easily after folding for three times, indicating good mechanical flexibility for free-standing electrodes. Coupled with the excellent mechanical flexibility, high specific capacitance, and simple fabrication process, the flexible and free-standing Co3O4-CNFs with hierarchical porous structure could be promising electrode materials for energy storage applications. Flexible and porous Co3O4-carbon nanofibers were prepared by electrospinning and carbonization,which can be used as free-standing electrodes for supercapacitors.