Scalable Assembly of High-Quality Graphene Films via Electrostatic-Repulsion Aligning.

Abstract

Assembling pristine graphene into freestanding films featuring high electrical conductivity, superior flexibility, and robust mechanical strength aims at meeting the all-around high criteria of new-generation electronics. However, voids and defects produced in the macroscopic assembly process of graphene nanosheets severely degrade the performance of graphene films, and mechanical brittleness often limits their applications in wide scenarios. To address such challenges, an electrostatic-repulsion aligning strategy is demonstrated to produce highly conductive, ultraflexible, and multifunctional graphene films. Typically, the high electronegativity of titania nanosheets (TiNS) induces the aligning of negatively charged graphene nanosheets via electrostatic repulsion in the film assembly. The resultant graphene films show fine microstructure, enhanced mechanical properties, and improved electrical conductivity up to 1.285 × 105 S m-1 . Moreover, the graphene films can withstand 5000 repeated folding without structural damage and electrical resistance fluctuation. These comprehensive improved properties, combined with the facile synthesis method and scalable production, make these graphene films a promising platform for electromagnetic interference (EMI) shielding and thermal-management applications in smart and wearable electronics.