Liquid metal incorporated graphene oxide films with enhanced through-plane thermal conductivity and flame resistance

With the recent upsurge in electronic and telecommunications industries, there is an extensive demand for thermal interface materials (TIMs) with integrated high thermal conductivity and flame resistance to ensure the performance, lifetime, and safety of electronic devices. Traditional polymer-based TIMs have failed to meet this demand owing to their inherent weaknesses like the utilization of rigid fillers, low through-plane conductivity, and poor thermal stability. Recently, graphene-based films have attracted considerable attention to use as TIMs due to pristine graphene's excellent in-plane thermal conductivity (2000–5000 Wm−1K−1). However, unsatisfactory through-plane thermal conductivity (<0.1 Wm−1K−1), resulting from the horizontally stacked graphene sheets, remains a major challenge in designing graphene-based TIMs for practical applications. Herein, we design a liquid metal (Galinstan) incorporated graphene oxide (GO) films with improved through-plane thermal conductivity and flame resistance via a combined solution mixing and vacuum filtration method. Gallium from the liquid metal Galinstan reacts with GO and reduces it while constructing heat transfer pathways along the through-plane direction. The resultant composite film demonstrates a through-plane thermal conductivity of 0.42 Wm−1K−1, which is much better than graphene oxide films (0.01 Wm−1K−1) and previous similar studies. Moreover, it has excellent thermal stability and can withstand an alcohol flame for 30 s, proving its potential to meet the ever-increasing demand for TIMs.