Lightweight Aligned Graphite Foams With High Through‐Plane Thermal Conductivity

Advanced thermal management materials with high through‐plane thermal conductivity and low density are highly in demand in electronics or energy storage. It is still challenging to produce such materials through an efficient and cost‐effective route. Here, we develop a new strategy to prepare aligned graphite foams (AGFs) from industrial‐grade worm graphite. Water serves as an in situ pore‐forming sacrificial template, and pressure‐induced orientation of graphite flakes creates a highly aligned structure with sufficient through‐plane thermal conduction pathways. Through formulation optimization, the AGF exhibits a high through‐plane thermal conductivity of 65.7 W·m −1 ·K −1 and a compressive modulus of 438 MPa at a low density of 0.61 g·cm −3 . Based on this optimal formulation, tuning the AGF to a density of 0.65 g·cm −3 further compacts the conductive network, resulting in an electrical conductivity of 242.8 S·m −1 and an electromagnetic interference shielding effectiveness of 63.31 dB. Moreover, by encapsulating paraffin into the AGF, the resultant composites achieve a steady‐state temperature of 81.8°C at 1.14 V via Joule heating. As a proof‐of‐concept for solar thermoelectric applications, it successfully powers a 1.5 V device under 3‐sun irradiance. Overall, it provides an efficient and cost‐effective strategy to overcome the trade‐off between low density and high through‐plane thermal conductivity.