From Waste to Function: Phase Change Composites of Lead-Containing Recycled Nanosilica/ Paraffin/Silicon rubber

Polymeric Phase Change Materials (PCMs) are widely used for energy storage and thermal management, but their performance is often limited by leakage, low latent heat, and poor thermal conductivity. This study addresses these challenges by utilizing recycled lead-containing silica (Pb-silica) from spent lead-acid battery separators as a supporting material for form-stable PCMs (FSPCMs) integrated into a silicone rubber matrix. The composites were characterized using FESEM, EDS, ICP, BET, DLS, FTIR, DSC, thermal conductivity, and tensile testing, alongside leakage behavior evaluations. Results show that Pb-silica provides a latent heat of ∼88 J/g, comparable to commercial silica, with slightly higher leakage due to its lower specific surface area. Importantly, the incorporation of Pb-silica increased the thermal conductivity by up to 40.7% compared with silicone rubber, whereas the corresponding increase achieved with commercial A70-silica was 19.1%. This work presents a potential approach for utilizing battery waste to produce form-stable PCMs for thermal management applications.