Enhanced interfacial thermal conductivity of functionalized boron nitride/polyvinyl alcohol/octadecane composite phase-change materials towards effective thermal management

Composite phase-change materials (CPCMs) with leakage-free phase transition are widely used in electronic devices and lithium batteries for efficient thermal management. However, the current CPCMs suffer from low thermal conductivity, which hampers their heat transfer efficiency. This study proposes a novel CPCM based on a functionalized boron nitride nanosheet (BNNS)/polyvinyl alcohol (PVA) porous skeleton infused with n-octadecane (Oct). The interfacial compatibility between BN/PVA is enhanced by employing (3-aminopropyl) triethoxysilane (KH550) as a bridging agent. Experimental investigations and molecular dynamics simulations demonstrate that KH550-modified BNNS exhibits lower interfacial thermal resistance (ITR) to PVA compared to hydroxy (-OH) and dopamine (DA)-modified counterparts. The resulting BNNS-KH550/PVA/Oct CPCM exhibits exceptional latent heat value of 171.95 J g⁻¹, high thermal conductivity of 0.839 W m⁻¹ K⁻¹, remarkable compressive strength of 3.82 MPa, with excellent electrical insulation and minimal leakage issues. These outstanding comprehensive performances of the CPCM validate its potential applications.