Battery-supercapacitor hybrid device based on agarics-derived porous nitrogen-doped carbon and 3D branched nanoarchitectures CNTs/Ni(OH)2

Abstract

Design and fabrication of electrochemical energy storage systems with both high energy and power densities are of great importance. The battery-supercapacitor hybrid device (BSH), as one of these systems, has attracted enormous attentions. In this study, a battery-supercapacitor hybrid device was successfully fabricated by using the resultant 3D branched nanoarchitectures carbon nanotubes/Ni(OH)2 (CNTs/Ni(OH)2) as a positive electrode and the hierarchically porous, nitrogen-doped, interconnected carbon nanosheets (HPN-CNS) as the negative electrodes, respectively. HPN-CNS were prepared from agaric through simultaneous carbonization, activation, and nitrogen-doping method, while 3D branched nanoarchitectures CNTs/Ni(OH)2 were prepared by deposited Ni(OH)2 nanosheets on the highly conductive CNTs by a single-step chemical bath deposition. Because of their unique structure, both of the two materials exhibited excellent electrochemical performance. The as-assembled BSH delivered a high energy density of 34 W h kg-1 along with power density of 0.8 kW kg−1, even at the power density of 16 kW kg−1, energy density still hold at 22.2 W h kg-1 with the high potential window of 1.6 V. Furthermore, the device showed a good cycling stability with capacitance retention of 75% after 2000 cycles. Such results showed that HPN-CNS and CNTs/Ni(OH)2 could be expected to serve as promising candidates for assembling high-performance BSH devices.