A Dual Carbon Lithium-Ion Capacitor Using Recycled Polymer Separator Derived Carbon Cathode and Graphite Anode from Spent Lithium-Ion Battery

Abstract

Lithium-ion capacitors (LICs) are hybrid capacitors that target pushing the energy limits of conventional supercapacitors by incorporating a lithium-ion battery (LIB)-type electrode without compromising much on the power density and cycle life of capacitors. Herein, a LIC is assembled using an ordered porous carbon cathode derived from the recycled polymer separator of spent LIBs and recycled graphite anode from the same source. The carbon-rich polymer is thermally stabilized and carbonized to utilize its porosity for ion storage and ordered matrix for better electronic conduction. The cathode half-cell delivers a capacitance of ∼100 F g−1 till 1000 cycles at 1 A g−1. In contrast, the anode half-cell delivers a capacity of 130 mAh g−1 under similar conditions. The assembled LIC provides an energy density of 129 Wh kg−1 at a power density of 275 W kg−1 and 54 Wh kg−1 at a high-power density of 13750 W kg−1. The LIC cycles with >70% capacitance retention till 6000 cycles. Further, the ion-storage mechanism of the LICs as well as their capacitive and diffusion-type contribution, is studied. The self-discharge and leakage current tests were performed in the cells to understand their practical feasibility.