Universal Coating Strategy Breaks Stability-Performance Trade-Off in Macroscopic Graphene Films

Macroscopic graphene film (MGF), excelling in superior electric and thermal conductivities, holds great promise in energy storage, thermal management, and flexible electronics. However, the high graphitization of MGF leads to surface fragility because of the weak interlayer interaction, leading to severe performance limitations. Herein, we report an interface engineering strategy for the thinnest coating on MGF to date, significantly enhancing surface stability while preserving ultrahigh electric and thermal conductivities. With a surfactant-enhanced interface self-assembly strategy, we construct a 5 nm thick Triton X-100-enhanced graphene oxide coating on MGF (MGF@TGO). This modification increases the surface adhesion by 206.36% while maintaining over 99% of its electrical and thermal conductivities. MGF@TGO serves as an effective thermal management unit, exhibiting excellent stability without surface detachment under simulated operating conditions. Depth profiling characterizations reveal that hydrogen bonding and π-π stacking costrengthen the MGF@TGO surface. Notably, our strategy is universally applicable to multiple aromatic-polar amphiphilic surfactants. This work successfully balances surface stability with performance retention, offering a scalable solution for MGF applications in industry.