Precisely controllable oxygen vacancy-manufactured Ov-Co3O4@PPy for high energy density supercapacitor

Effective controllable manufacturing oxygen vacancy and polypyrrole coating can optimize the capacitive and cyclic properties of Co 3 O 4 . Herein, composition of O v -Co 3 O 4 @PPy with Co 3 O 4 rich in oxygen vacancy defects and polypyrrole was synthesized using NaBH 4 reduction and chronoamperometry. O v -Co 3 O 4 was synthesized while regulating the concentration of the reducing agent NaBH 4 solution, and then O v -Co 3 O 4 @PPy was synthesized by electrodeposition of PPy. The specific capacitance of O v -Co 3 O 4 @PPy formed at an optimal NaBH 4 concentration and electrodeposition time was about three times that of Co 3 O 4 without reduction treatment and unwrapped PPy. The capacitance retention rate of O v -Co 3 O 4 @PPy was close to 80.5% after 5000 cycles. In addition, O v -Co 3 O 4 @PPy//AC asymmetric supercapacitor was assembled with the as-prepared O v -Co 3 O 4 @PPy as the positive electrode material and activated carbon as the negative electrode, which yielded specific energy density up to 74.55 Wh kg −1 at 850 W kg −1 power density and a capacitance retention rate close to 110% after 10,000 cycles.