Perspective on phase change composites in high-efficiency solar-thermal energy storage

To clarify future research directions, this study first analyzes the heat transfer process of solar-thermal conversion and then reviews solar-thermal phase change composites for high-efficiency harnessing solar energy. The focus is on enhancing heat absorption and conduction while aiming to suppress reflection, radiation, and convection. Most advancements have concentrated on improving absorption and thermal conductivity, while reducing the aforementioned unfavorable processes remains less explored. In the current research, the best results show that the solar-thermal conversion efficiency has approached the theoretical limit (100%), and a typical thermal conductivity has reached 33.5 W/(m·K). However, further enhancement of the absorption and conduction remains a challenge, highlighting the need for structural modifications and grafting. Other factors hindering conversion efficiency have received limited attention and warrant further in-depth investigation, with the potential to reduce reliance on fossil fuels and contribute to environmental sustainability.