Super-flexible phase change materials with a dual-supporting effect for solar thermoelectric conversion in the ocean environment†
Abstract
Solar thermoelectric generators (STEGs) based on phase change materials (PCMs) are an emerging advanced technology to collect and utilize solar energy. However, it is still challenging for photo-driven PCMs to make use of the huge amount of solar energy in oceans due to their limited shape stability and stability underwater. Herein, dual-supporting super-flexible PCMs (SFPCMs) comprising a natural rubber (NR) continuous network and island-like dispersed paraffin wax (PW) microcapsules were developed. The interaction between the NR matrix and phase change microcapsules (PCMCs) was further improved by incorporating a small amount of MXene to enhance the photo-absorption ability, mechanical performance, and thermal conductivity of the composite PCMs. In addition to excellent stretchability and compressibility, this dual-supporting structure consisting of a continuous NR network and encapsulated polyurethane (PU) shell endowed SFPCMs with unprecedented leakage resistance and underwater stability, even in various harsh environments. More impressively, a proof-of-concept STEG based on SFPCMs with a photothermal conversion efficiency of up to 92% was proposed, exhibiting excellent cycling output stability in a simulated ocean environment with an output voltage of 410 mV. This work expands the application potential of photo-driven PCMs to efficiently harvest solar energy from the ocean environment.