Foaming-induced structural engineering of graphite arrays for high-density thermal pathways in thermal interface materials

The escalating power density of electronics demands advanced thermal interface materials (TIMs). While graphite array-based TIMs (GRTs) have attracted considerable interest, achieving their theoretically high performance requires precise microstructural control. Structural models indicate that reducing the thickness of graphite lamellae increases the density of effective thermal pathways, which is key to enhancing GRT performance. Herein, we develop a hydrazine monohydrate-assisted foaming strategy that enables microstructural engineering of graphene oxide paper. Through systematic modulation of the hydrazine monohydrate concentration, precise control over the lamellae thickness in the derived graphite papers was achieved, which directly governs the thermal pathway density in the final GRT architecture. This structural advantage yields higher-density thermal pathways in vertical arrays, enabling the optimal GRT to achieve an ultra-low total thermal resistance of 5.7 × 10−6 m2 K W−1 and high through-plane thermal conductivity of 130.6 W m−1 K−1. This study establishes a fundamental structure–property relationship in GRTs, revealing that thermal performance is critically dependent on the architectural design of the conductive network at the micro/nanoscale. The proposed strategy offers a promising and scalable route for manufacturing advanced thermal management solutions to meet the escalating cooling demands of next-generation high-power electronics.