The synergistic effect of carbon and polypyrrole co-coating enhances the electrochemical performance of TiO2 microspheres for high-performance supercapacitors

Carbon and polypyrrole co-coated TiO 2 microspheres (TiO 2 @NC@PPy) electrodes were synthesized by hydrothermal, coating and potentiostatic deposition. The carbon coating layer and polypyrrole layer can significantly improve the conductivity of the electrode, and the unique hierarchical porous microsphere structure can adsorb PPy, preventing its structural decomposition and volume expansion while enhancing the cycle stability. Therefore, the areal capacitance was increased from 2.26 mF/cm 2 to 389.76 mF/cm 2 at a current density of 2 mA/cm 2 , retaining 73.34% capacity after 2000 cycles.