Ultrahigh Conductive Graphene Paper Based on Ball‐Milling Exfoliated Graphene

Due to low density, extremely high electrical and thermal conductivities, graphene has great potential to construct lightweight thermal conductive paper for high‐power electric devices. However, the remarkable properties of graphene are on a molecular level and difficult to achieve when processed into macroscopic paper. Here, an effective route to construct ultrahigh conductive graphene paper is developed. First, large‐volume, high‐concentration, plane‐defect‐free, few‐layer graphene dispersion is fast produced from graphite at high yield through ball milling. The exfoliated graphene dispersion is further processed into graphene paper through fast filtration, thermal treatment, and mechanical compression. The electrical and thermal conductivities of the resultant graphene paper are as high as 2231 S cm −1 and 1529 W m −1 K −1 , superior to previously reported graphene papers. Structural analyses confirm that the ultrahigh conductivities are attributed to high quality of graphene sheets, their compact ordered stacking, and large graphitic crystalline domain size, which improve electron and phonon transport within basal plane of graphene sheet and between graphene sheets.