Target-oriented electrode constructions toward ultra-fast and ultra-stable all-graphene lithium ion capacitors

Lithium ion capacitors (LICs) with a 3–5 times higher energy density than traditional electrochemical double-layer capacitors (EDLCs), are thus considered as next generation of capacitive energy storage systems (cESSs). However, the introduction of a battery-type anode into hybrid configuration inevitably leads to scarified power density and cycling life in comparison with EDLCs, due to the imbalanced electrochemical performance of two electrodes resulted from distinct energy storage mechanisms, which means achieving competitive power density and cycling life simultaneously is an extreme challenge involving in the whole system. In this context, we rationally design an ultra-fast and ultra-stable all-graphene LIC, for which various graphene electrode constructions are synthesized orienting in the distinct energy storage principles of two electrodes, and a novel match approach derived from quasi-in-operando EIS technologies for two electrodes is proposed and applied. These systemic optimizations enable an ultra-fast and ultra-stable electrochemical performance of all-graphene LIC, which delivers an ultra-high-power density of 53,550 W kg⁻¹ and an unprecedented cycling stability of 98.9% retention after 50,000 cycles. These results are promising in terms of pushing next generation of cESSs by combining considerable electrode constructions and match approaches.