A high-power lithium-ion hybrid electrochemical capacitor based on citrate-derived electrodes

Achieving high-power lithium-ion hybrid electrochemical capacitor (Li-HEC) through facile and low-cost synthesis procedures is still quite challenging. In this work, starting from daily used food additives, nitrogen-doped hierarchical porous carbon (N-HPC) was prepared through facile pyrolysis of magnesium citrate and subsequent NH3 treatment, and carbon-coated Fe2O3 (Fe2O3@C) was synthesized by thermal decomposition of ferric citrate and following heat treatment in air, respectively. As-prepared N-HPC and Fe2O3@C were separately employed as cathode and anode materials to fabricate a high-power, which delivers a high energy density of 65 W h kg−1 at 368 W kg−1, and 31 W h kg−1 at a high power density of 9.2 kW kg−1. And it remains 84.1% capacity over 1000 galvanostatic charge-discharge cycles at 1 A g−1.