Nitrogen-doped activated porous carbon for 4.5 V lithium-ion capacitor with high energy and power density

Abstract

Lithium-ion capacitors (LICs) have become one of the most popular energy storage devices because of the combination of high energy densities and power densities. However, the kinetic imbalance of anode and cathode restricts the specific capacities and voltage windows of LICs. Herein, an in-situ nitrogen-doped activated porous carbon (ANMPC) material with high specific surface area (1894.9 m2/g) is proposed to act as both cathode and anode for the preparation of the 4.5 V “all carbon” LICs. The hierarchically porous ANMPC obtained by KOH activation and carbonization of polypyrrole (PPy) has plenty of mesopores created by surfactant (added during the PPy process) as well as micropores generated by KOH activation, thus can provide abundant active sites for ion intercalation and large area for electrostatic adsorption simultaneously, satisfying the critical requirements of high-performance anode and cathode, respectively. After coupling the pre-lithiated ANMPC anode and fresh ANMPC cathode, the complete LIC device delivers large energy density of 167.5 Wh/kg at a power density of 269.0 W/kg, and still remains 88.9 Wh/kg at an ultrahigh power density of 13,198.5 W/kg, exhibiting enormous potential for applications in high performance lithium-ion capacitors.