Freestanding graphene paper supported three-dimensional porous graphene-polyaniline nanocomposite synthesized by inkjet printing and in flexible all-solid-state supercapacitor.

Freestanding paper-like electrode materials have trigged significant research interest for their practical application in flexible and lightweight energy storage devices. In this work, we reported a new type of flexible nanohybrid paper electrode based on full inkjet printing synthesis of a freestanding graphene paper (GP) supported three-dimensional (3D) porous graphene hydrogel (GH)-polyaniline (PANI) nanocomposite, and explored its practical application in flexible all-solid-state supercapacitor (SC). The utilization of 3D porous GH scaffold to load nanostructured PANI dramatically enhances the electrical conductivity, the specific capacitance and the cycle stability of the GH-PANI nanocomposite. Additionally, GP can intimately interact with GH-PANI through π-π stacking to form a unique freestanding GP supported GH-PANI nanocomposite (GH-PANI/GP) with distinguishing mechanical, electrochemical and capacitive properties. These exceptional attributes, coupled with the merits of full inkjet printing strategy, lead to the formation of a high-performance binder-free paper electrode for flexible and lightweight SC application. The flexible all-solid-state symmetric SC based on GH-PANI/GP electrode and gel electrolyte exhibits remarkable mechanical flexibility, high cycling performance and acceptable energy density of 24.02 Wh kg(-1) at a power density of 400.33 W kg(-1). More importantly, the proposed simple and scale-up full inkjet printing procedure for the preparation of freestanding GP supported 3D porous GH-PANI nanocomposite is a modular approach to fabricate other graphene-based nanohybrid papers with tailorable properties and optimal components.