Bimodal porous carbon cathode and prelithiated coalesced carbon onion anode for ultrahigh power energy efficient lithium ion capacitors

Lithium ion capacitors made using prelithiated coalesced carbon onion based anode showed excellent high energy and power performance with time constant in the order of similar to 1.45s. The interconnected carbon onion microstructure facilitated both rapid electron and ion transport thereby minimizing the overall resistance. Additionally, high specific capacitance was achieved through control of pore size distribution in high surface area carbons derived from polyfurfuryl alcohol based polymer blends. The fabricated capacitors can be charged and discharged in less than 30s between 2.2V - 4V with energy efficiencies >90%. The maximum achievable energy density was 120 Wh/kg with the capacitor retaining 77 Wh/kg even at a high power density of 11 kW/kg. The capacitors also demonstrated excellent cycling stability with 80% capacitance retention over 21000 cycles along with good thermal stability up to 60 degrees C. (C) 2019 Elsevier Ltd. All rights reserved.