Flexible graphene-based composite films for energy storage devices: From interfacial modification to interlayer structure design

Abstract

The advancement of flexible electronics relies heavily on the progress in flexible energy storage device technology, necessitating innovative design in flexible electrode materials. Among numerous potential materials, graphene-based composite films emerge as promising candidates due to their capacity to leverage the superior electrochemical and mechanical properties of graphene flakes. However, the influence of strong van der Waals forces often leads to inevitable agglomeration and self-stacking of adjacent graphene flakes. Consequently, achieving an elaborate control over the interlayer structure of graphene-based composite films becomes imperative to improve their structural stability in electrolytes and enhance charge/electron transfer efficiency. Herein, this review provides a comprehensive overview of diverse interfacial functional modification strategies for graphene and graphene oxide nanoflakes, thereby facilitating the assembly of graphene-based composite films. Additionally, it encompasses a discussion on the universal designs of micro-nanostructures within interlayers. Particularly, the technologies to manipulate, stabilize and orientate the interlayer channels and interlayer spacing are highlighted. These insights serve as an informative reference for the engineering of interlayer structures in graphene-based composite films. Furthermore, the review addresses the potential applications of flexible graphene-based composite films in wearable applications, current challenges, and future directions.