Interface-Engineered BN/MXene Composites for Anisotropic Thermal Conduction and Solid-Solid PCM Buffering

The rational design of phase-change composites that simultaneously deliver high thermal conductivity, intrinsic electrical insulation, and structural integrity is crucial for advanced thermal management and energy-regulation technologies. Herein, we report an interface-engineered anisotropic hybrid aerogel composed of amine-functionalized boron nitride ( f -BN) and Ti 3 C 2 T x MXene, fabricated via a dual-polymer-assisted gelation strategy combined with directional freeze-casting. By engineering chemically bonded yet electrically insulating interfaces through B-N-NH 2 bridges, Ti-O-C/N linkages, and π – π interactions, the system establishes a phonon-dominated transport network that overcomes the intrinsic trade-off between thermal conduction and electrical insulation. The aligned lamellar architecture further promotes efficient through-plane heat transport. Upon incorporation into a polyurethane-based solid-solid phase-change matrix, the composite achieves a high thermal conductivity of 3.376 W m −1 K −1 at a low filler loading of 14 wt.%, while retaining a substantial latent heat of 108 J g −1 and high electrical resistivity (1.68 × 10 12 Ω·cm). The composite exhibits excellent cycling stability (>96% retention after 100 thermal cycles) and delivers significant temperature reductions in CPUs (10.0°C) and Li-ion battery modules (≈7.6°C). This work establishes a design paradigm for electrically insulating, high-performance phase-change composites with synergistic heat transport and energy buffering.