MXene-Integrated Solid-Solid Phase Change Composites for Accelerating Solar-Thermal Energy Storage and Electric Conversion

High Latent Heat and Recyclable Phase-Change Materials for Photothermoelectric Conversion

Realizing organic phase-change material networks with excellent recyclability while maintaining high latent heat still faces great challenges due to the difficult trade-off between network composition. Herein, the high latent heat and recyclable phase-change materials (RPCMs) were developed by integrating linear poly(ethylene glycol) (PEG) multimers as phase-change components and the dynamic covalent cross-linking polyurethane network components in a semi-interpenetrating polymer network structure. The latent heat (54.7-145.0 J/g) can be readily tuned by the weight fraction of linear PEG multimers and the molecular weight of PEGs used in RPCMs. The RPCMs have excellent recyclability/reprocessability with activation energy of 81.23-125.84 kJ/mol by introducing dynamic disulfide bonds in the cross-linking network structure components in RPCMs while enabling the adjustable mechanical stress (10.72-14.04 MPa) and strain (7.40-266.22%), high thermal reliability, and high thermal stability. Efficient photothermal RPCMs were realized by introducing polydopamine particles in the RPCM matrix. The thermal management system and the photothermoelectric generator were designed based on the advantages of high latent heat and efficient photothermal ability of RPCMs and further demonstrated the excellent thermal management ability and photothermoelectric properties.

A Novel Thermal Interface Material Composed of Vertically Aligned Boron Nitride and Graphite Films for Ultrahigh Through-Plane Thermal Conductivity

The relentless drive toward miniaturization in microelectronic devices has sparked an urgent need for materials that offer both high thermal conductivity (TC) and excellent electrical insulation. Thermal interface materials (TIMs) possessing these dual attributes are highly sought after for modern electronics, but achieving such a combination has proven to be a formidable challenge. In this study, a cutting-edge solution is presented by developing boron nitride (BN) and graphite films layered silicone rubber composites with exceptional TC and electrical insulation properties. Through a carefully devised stacking-cutting method, the high orientation degree of both BN and graphite films is successfully preserved, resulting in an unprecedented through-plane TC of 23.7 Wm-1 K-1 and a remarkably low compressive modulus of 4.85 MPa. Furthermore, the exceptional properties of composites, including low thermal resistance and high resilience rate, make them a reliable and durable option for various applications. Practical tests demonstrate their outstanding heat dissipation performance, significantly reducing CPU temperatures in a computer cooling system. This research work unveils the possible upper limit of TC in BN-based TIMs and paves the way for their large-scale practical implementation, particularly in the thermal management of next-generation electronic devices.