A PCM-enhanced thermoelectric generator with enhanced power density and lifespan

Waste heat harvesting with thermoelectric generators (TEGs) is fundamentally limited by low conversion efficiency and operational instability, particularly under conditions of fluctuating external temperatures. Here, we propose a novel sandwich-style TEG to achieve high-efficiency waste heat harvesting and conversion. The design is based on a phase change material-integrated thermoelectric generator (PCM-TEG), fabricated by sandwiching TEG modules between two layers of PCMs. This architecture transforms passive thermal storage into active energy conversion, thereby unifying efficient heat management with continuous power generation. The synergistic design addresses long-standing challenges including poor energy conversion efficiency, thermal oxidation, and short discharge duration. By employing thermally conductive electrodes and composite PCMs, the system maintains high thermal storage capacity while enabling stable, long-term electricity output from otherwise wasted heat. Experiments reveal a >100% enhancement in effective power density and a fivefold improvement in output stability and device lifetime. These results establish the PCM-TEG as a promising platform for next-generation thermoelectric battery systems, offering scalable solutions for sustainable energy storage, waste-heat utilization, and thermal insulation technologies.