Development and characterization of Li-ion capacitor pouch cells

High energy density Li-ion capacitor (LIC) pouch cell prototypes were assembled with lab-scale equipment using activated carbon cathode and hard carbon/lithium stabilized metal power (SLMP) anode. The specific energy and energy density as high as 30 Wh kg−1 and 39 Wh L−1 have been achieved, respectively. The pouch cells can deliver over 50% of the maximum stored energy at a discharge rate over 100 C-rate. After 10,000 cycles, the LIC pouch cell still has 80% of the initial capacitance. The average leakage current is 0.3 μA cm−2 during the first 72 h. •The specific energy and energy density are 30 Wh kg−1 and 39 Wh L−1, respectively.•The capacitor was discharge at rates over 100 C rate.•The capacitor was cycled over 10,000 cycles with capacitance degradation