Synthesis of hollow carbon spheres from polydopamine for electric double layered capacitors application

This paper reports a surfactant-assisted template method for synthesis' of hollow carbon nanospheres by using polydopamine (PDA) as carbon source and ZnO as template. In the help of surfactant micelles, spherical ZnO particles are firstly formed and then coated with PDA films at room temperature without structure damage by the alkaline conditions needed for self-polymerization of dopamine. After carbonization in NZ atmosphere followed by ZnO removal, hollow carbon spheres with adjustable particle size (150-300 nm), high specific surface area (SSA, similar to 1100 m(2) g(-1)) and optimized mesopore size distribution are obtained. The effects of surfactant content and carbonization temperature on the morphology and the electrochemical properties of the as-prepared carbons have been further investigated. The hollow carbon spheres obtained at optimum synthetic conditions exhibit outstanding electrochemical properties including high capacitance (156 F g(-1) at 2 mV s(-1)) and rate capability (125 F g(-1) even at 200 mV s(-1)) as well as cycling stability with 98% capacitive retention after 16,000 cycles, suggesting that it is a promising electrode material for the application of electric double layered capacitors.