High Performance Li-Ion Capacitor Laminate Cells Based on Hard Carbon/Lithium Stripes Negative Electrodes

High performance Li-ion capacitor (LIC) laminate cells have been fabricated with activated carbon positive electrodes (PEs) and hard carbon/lithium stripes negative electrodes (NEs). The lithium stripes on the surface of NEs enable a novel pre-lithiation approach for the LIC cells. The LIC laminate cells can achieve a maximum specific power of 6 kW kg−1 and a maximum power density of 12 kW L−1. The specific energy and energy density of the LIC laminate cells are 14 Wh kg−1 and 28 Wh L−1 respectively, which is about 3 times of the traditional electric double layer capacitors (EDLCs). The DC life of such LIC cell has passed 2000 h testing while held at maximum operation voltage 3.8 V and 65°C. Extended cycle performance under 50 C rate of the LIC laminate cell has been tested: such LIC can remain 89% of the original discharge capacitance after 100,000 cycles without obvious changes in ESR value. When the LIC cell is charging and discharging under 125 C rate, the cycle life is still more than 50,000 cycles.