Overcoming Mechanical‐Thermal Trade‐Off in Aerogel‐Encapsulated Phase Change Composites via Biomimetic Honeycomb Engineering

Passive thermal management systems that utilize phase change materials (PCMs) demonstrate significant potential in addressing the challenges of electronic overheating, but the low associated thermal conductivity and liquid PCM leakage hinder practical applications. Aerogel encapsulation can deal with these technical limitations, but the aerogels exhibit structural collapse under thermal-mechanical stress. In this study, a biomimetic honeycomb strategy is proposed for the fabrication of mechanically robust and thermally conductive honeycomb graphene/calcium alginate aerogels used in PCM encapsulation. The synergy associated with biomimetic structure and compositional strengthening delivers a honeycomb aerogel with a specific strength of 19.2 kN m kg^-1 at 20% strain. The deposition of a continuous graphene layer on the honeycomb walls generates efficient thermal conductive pathways. Following paraffin encapsulation, the phase change composite demonstrates a post-phase-change compressive strength of 2.49 MPa, an enhanced thermal conductivity (4.18 W m^-1 K^-1), and a high melting enthalpy (199.0 J g^-1). The resultant composite exhibits a multifunctional synergy in mechanical support, thermal conduction, and heat storage. The proposed biomimetic honeycomb strategy can serve as a controllable and flexible approach to constructing aerogels with coupled mechanical robustness and multifunctional capabilities.