High-performance and flexible all-solid-state hybrid supercapacitor constructed by NiCoP/CNT and N-doped carbon coated CNT nanoarrays

Abstract The exploration of flexible supercapacitors with high energy density is a matter of considerable interest to meet the demand of wearable electronic devices. In this work, with carbon nanotubes (CNTs) grown on carbon cloth (CC) as flexible substrate, NiCoP nanoflake-surrounded CNT nanoarrays (NiCoP/CNT) and N-doped carbon coated CNT nanoarrays (CNT@N-C) were synthesized on CC and utilized as cathode and anode materials for constructing flexible all-solid-state hybrid supercapacitor. Both them exhibit excellent electrochemical performance. NiCoP/CNT/CC composites can deliver a specific capacitance of 261.4 mAh g−1, and CNT@N-C/CC exhibits a high capacitance of 256 F g−1 at the current density of 0.5 A g−1. The hybrid supercapacitor built from the two well designed electrodes can provide a specific capacitance of 123.3 mAh g−1 at current density 1 mA g−1 within a potential window of 0–1.5 V and retain almost 85% of its initial capacitance after 5000 cycles. Furthermore, the flexible devices show the maximum energy density of 138.7 Wh kg−1 and a power density of 6.25 kW kg−1, obviously superior to some recent reported supercapacitor devices, indicating its potential in practical application.