All-Carbon Hybrid Mobile Ion Capacitors Enabled by 3D Laser-Scribed Graphene

Abstract

Hybrid mobile ion capacitors (HMIC) are proposed as a way to incorporate the advantages of both batteries and supercapacitors into one system. Unfortunately, considering the much slower Li+ intercalation/deintercalation process, finding a suitable battery anode material with a high rate performance is still a major challenge. Herein, the fabrication of nitrogen-doped laser-scribed graphene (NLSG) with a 3D structure as a binder-free and conductive additive-free anode is reported. This NLSG anode has high nitrogen and oxygen doping (8.6 and 6.3 at%), leading to the formation of conductive electrodes with an expanded lattice spacing, providing more convenient pathways and reaction sites for Li+ ions. Hybrid Li-ion capacitors (HLICs) are assembled by combining the NLSG anodes with hierarchical porous carbon (PC) cathodes. The NLSG//PC HLICs show an energy density (including the total weight of two electrodes) of 186 Wh kg−1 at 200 W kg−1. Even when power density increases to the level of conventional supercapacitors (20 kW kg−1), an energy density of 76 Wh kg−1 is still be obtained. Further, the devices exhibit excellent cycle life, retaining 87.5% of the initial value after 5000 cycles. Herein, laser-scribed graphene is demonstrated as a very promising electrode for mobile ion capacitors.