All‐in‐All: Dead Lithium‐ion battery to active Lithium‐ion Capacitor

Here, we have developed lithium‐ion capacitors (LICs) with all the components, except the electrolyte solution, effectively recycled from the spent Lithium‐ion batteries. Hybrid capacitors, such as LICs, are potential breakthroughs in electrochemical energy storage devices, where most research is focused. These devices can simultaneously guarantee high energy and power by hybridizing battery‐type and capacitive‐type electrodes. We have successfully upcycled the graphite, current collector, separator, etc., from the spent LIBs to fabricate a high‐performance LIC. Our LIC consists of recovered graphite (RG) coated over recovered copper foil as an anode, recycled polypropylene as the separator, and reduced graphene oxide (rGO) synthesized from RG as the cathode. The RG half‐cell exhibited an specific capacity of 302 mAh/g even after 75 charge‐discharge cycles with a coulombic efficiency of >99%. The Li/rGO displayed remarkable cycling performance for over 1000 cycles with high stability and reversibility. Subsequently, the pre‐lithiated RG (p‐RG) electrode is paired with the rGO electrode under the balanced loading conditions to construct LIC, rGO/p‐RG, delivering a maximum energy density of 185 Wh/kg with ultra‐long durability of more than 10,000 cycles. The possibility of LIC under different climatic conditions is also explored, and its remarkable performance under various temperature conditions is worth mentioning.