Facile self-templating preparation of polyacrylonitrile-derived hierarchical porous carbon nanospheres for high-performance supercapacitors

A green, facile and efficient strategy was proposed to successfully synthesize polyacrylonitrile-derived hierarchical porous carbon nanospheres (HPCNs) for high-performance supercapacitors by surfactant-free emulsion polymerization followed with one-step KOH activation. The as-obtained HPCNs show favorable features for electrochemical energy storage such as a high specific surface area of up to 3130 m(2) g(-1), high volume of hierarchical pores up to 1.87 cm(3) g(-1), hierarchical porosity consisting of micro, meso, and macropores, turbostratic carbon structure, controlled and tunable pore size and stable thermal and chemical properties. The symmetric supercapacitor exhibits a reversible specific capacitance of 240 F g(-1) at a current density of 1 A gg(-1) and displays a high energy density of 77 W h kg(-1) at a power density of 875 W kg(-1). A high specific capacitance retention of 96% could be maintained even after 3000 cycles. Moreover, we used different electrolytes to study the capacitive behavior with controlled pore size. The facile, efficient and template-free synthesis strategy for novel HPCNs from polymer sources could find use in supercapacitors, lithium ion batteries and fuel cells.