Helical Carbon Fiber‐Based Phase Change Thermal Interface Materials: Unlocking Superior Thermal Conductivity through Novel Structural Engineering

Effective thermal management is critical for high‐performance electronics facing challenges of heat flux and interfacial conduction. Traditional carbon fiber‐based thermal interface materials (TIMs) and phase change thermal interface materials (PCTIMs) often fail to simultaneously achieve high through‐plane thermal conductivity (TC) and mechanical compliancedue to limitations in fiber alignment and material anisotropy. This study presents a paradigm‐shifting design of helical carbon fiber composite (HCFC) addressing these limitations. The helical architecture inherently aligns fibers along the z ‐axis, enabling enhanced through‐plane TC (2.97 W m − 1 K − 1 ) without complex alignment processes. HCFCs exhibit superior rebound rates exceeding 80%, ensuring reliable thermal contact under compression. Integrated into a paraffin wax matrix, the HCFC‐based PCTIM achieves a significantly improved through‐plane TC of 3.72 W m − 1 K − 1 , high latent heat (150 J g − 1 ), and minimal leakage (1.55 wt%). The helical structure enhances phase change material accommodation while sustaining performance across pressure/temperature variations. Leveraging cost‐effective Polyacrylonitrile‐based carbon fibers, this design surpasses traditional TIMs in both thermal and mechanical properties. This work establishes HCFC‐based TIMs/PCTIMs as scalable solutions for advanced thermal management in electronic and energy systems, addressing the growing demand for high‐performance materials.