Similar “relay race” capacitance behaviors of folded graphene films based high-performance supercapacitors

Abstract

Graphene film has a great planar electron transport characteristic, yet its vertical electron transport efficiency is limited due to the two-dimensional stacked structure, which restricts the wide implementation of graphene-based films in energy storage field, such as supercapacitors (SCs). Herein, we present a novel folding strategy to tackle this issue and enable preparation of high mass loading graphene film possessing high-performance. Folded reduced graphene oxide (F-rGO) films via low-temperature thermal reduction show the folded paper-like structure and an interesting electrochemical law. Briefly, by combining the capacitance performance of different fold films, the resulting films exhibit a capacitance retention behavior of similar “relay race”, rendering that their gravimetric capacitance always maintain high level value (>180 F g−1) at the range of 2–9 mg cm−2, and the volumetric capacitance can achieve ~232 F cm−3 even at 11.3 mg cm−2. Meanwhile, their areal capacitance also exhibits a relay-like and linear growth with increasing mass loading and eventually achieve ~3400 mF cm−2 at 17 mg cm−2. In addition, flexible all-solid state SCs assembled by the F-rGO films also present excellent electrochemical and structural stability under bending states. Therefore, we believe that folding technique is a meaningful way to produce high-performance graphene based electrodes.