Zn-assisted self-assembly synthesis of graphene/multi-walled carbon nanotubes hybrid films for high-performance wearable supercapacitors

Abstract

Graphene films based flexible supercapacitors exhibit huge application foreground for wearable electronics, but up to now, their preparations are always time-consuming and intricate, and their electrochemical characteristics and mechanical flexibilities are still far from satisfactory. In this study, we report a very facile and sustainable Zn-assisted self-assembly method to synthesize Graphene/MWCNTs films, in which multi-walled carbon nanotubes (MWCNTs) with various dosages are uniformly embedded between graphene sheets. Results demonstrate that, when the mass ratio of MWCNTs to GO is 1:6, the resultant Graphene/MWCNTs-4 has an ultrahigh area specific capacitance of 269.3 mF cm−2 at 1 mA cm−2, which is obviously higher than five other counterparts in present study as well as the graphene films in literatures. The Graphene/MWCNTs-4 based all-solid-state supercapacitor has a maximum energy density of 197.9 mWh m−2 at 4408.7 mW m−2, and a superior power density of 45396.2 mW m−2 at 40.1 mWh m−2. Additionally, great capacitive and mechanical stabilities with capacitance retentions of 76.2% over 50,000 cycles and 82% at bending angles from 0 to 120° are also exhibited. The remarkable properties endow Graphene/MWCNTs-4 with tremendous application potential in wearable energy storage.