Experimental investigation of gallium and hexagonal boron nitride composite-based PCM for battery thermal management

Effective thermal management is essential to ensure the safety, reliability, and performance of lithium-ion batteries (LIBs), particularly under high charge–discharge rates. In this study, a novel composite phase change material (CPCM) was developed by incorporating hexagonal boron nitride (h-BN) nanoparticles into gallium (Ga), alongside expanded graphite (EG) and paraffin (PA), to enhance thermal conductivity and latent heat storage. The CPCM was synthesized through a multi-component dispersion process, and its thermophysical properties were characterized using advanced analytical techniques. Results demonstrated that the inclusion of Ga and h-BN significantly improved the composite's thermal conductivity and altered its melting and crystallization characteristics, leading to enhanced heat absorption and release performance. Experimental validation was conducted using 18,650 LIB subjected to fast discharge rates of 2C to 5C. The CPCM successfully regulated battery surface temperatures to 38.0°C, 40.0°C, 41.2°C, and 43.3°C, respectively, mitigating thermal runaway risks. Beyond battery systems, the developed CPCM shows strong potential for broader thermal management applications, including solar energy storage in agrivoltaic systems, greenhouse integration, and building energy optimization, particularly in remote and off-grid agricultural environments. © 2026 The Authors. Published by Elsevier Ltd.