A High-Performance Dual-Ion Battery-Supercapacitor Hybrid Device Based on LiCl in Ion Liquid Dual-Salt Electrolyte

A dual-ion battery-supercapacitor hybrid device (DIB-SCHD), cleverly integrating a dual-ion battery (DIB) and a supercapacitor (SC), is expected to endow both the high energy density of dual-ion battery and the high power density of supercapacitor. Benefitting from the similar features of the electrolyte and symmetrical electrode configuration, a state-of-the-art DIB-SCHD is developed by using N-doped micropores-dominant carbon(N-MPC) as the electrode and LiCl in a room-temperature ion liquid hybrid as the electrolyte, which deliver an ultrahigh mass capacitance of 374 F g −1 with a high voltage of 3.5 V and a remarkable specific energy of 208 Wh kg −1 at 1144 W kg −1 and an ultrahigh specific power of 22834 W kg −1 at 77 Wh kg −1 . Combined with ex situ characterizations and theoretical calculations, the assembled DIB-SCHD presents a synergistic energy storage mechanism simultaneously involving ion intercalation/deintercalation and adsorption/desorption processes, which can promote the reaction kinetics and achieve exceptional electrochemical performance. The perfect integration of the dual-ion battery-type and supercapacitor-type electrodes provides a new strategy toward high energy and power density electrochemical energy storage devices.