Direct-Ink-Writing Printed Aerogels with Infiltrated Field’s Metal for High Thermal Conductivity and Shape Stability

The increasing power density of electronic devices demands thermal interface materials with efficient heat dissipation and structural stability. Phase-change thermal interface materials (PCTIMs) provide thermal buffering but are limited by low thermal conductivity and leakage during phase transitions. Here, a direct-ink-writing (DIW) strategy using a biobased multilayer graphene (MLG)/chitosan quaternary ammonium salt (CQAS)/cationic cellulose nanofiber (CCNF) composite ink (GQC) constructs vertically aligned porous aerogels. The GQC aerogels feature controllable 200–400 μm macroscopic channels, a vertically aligned internal porous architecture, and good mechanical compliance with a Young’s modulus of 0.322 ± 0.008 MPa. Pressure-assisted infiltration of Field’s metal (FM, 62.3 °C) forms a bicontinuous GQC/FM thermal network, in which continuous FM provides efficient heat-transfer pathways while the porous GQC framework confines molten metal. At 29 vol % FM, the composite achieves a through-plane thermal conductivity of 8.57 W m–1 K–1 and retains 95.0% of its initial value after 200 thermal cycles. Moreover, a simple alkali-assisted process recovers 92% of FM for reuse, yielding a regenerated composite with a thermal conductivity of 7.81 W m–1 K–1 (91.1% of the original value). This work presents a metallic PCTIM design integrating efficient heat transport, shape stability, and recyclability for sustainable thermal management.