High-performance all-solid state asymmetric supercapacitor based on Co3O4 nanowires and carbon aerogel

Abstract An all-solid state asymmetric supercapacitor has been fabricated using carbon aerogel (CA) microspheres as the negative electrode and Co 3 O 4 nanowires on nickel foam (Co 3 O 4 –NF) as the positive electrode separated by PVA-KOH membrane as the electrolyte. For the desirable porous structure, high specific capacitance and rate capability of CA and Co 3 O 4 –NF, broader potential window of the two electrodes, no binder and conductive agent added, the asymmetric supercapacitor can be cycled reversibly in a wide potential window of 0–1.5 V with an energy density of 17.9 Wh kg −1 at a power density of 750 W kg −1 . The energy density of the asymmetric supercapacitor is significantly improved in comparison with those of the symmetric supercapacitors based on CA (6.28 Wh kg −1 ) and Co 3 O 4 –NF (2.42 Wh kg −1 ). The asymmetric supercapacitor can also deliver a high energy density of 10.44 Wh kg −1 , even at a high power density of 7.5 kW kg −1 . In addition, the asymmetric device shows good stability with approximately 85% of its initial capacitance after 1000 cycles.