Efficient and stable solar-thermal energy storage via camel-hump-like adsorption strategy using nano-ribbon-modulated ultra-light self-standing film

The direct storage of solar energy using phase change materials (PCMs) holds great potential for optimizing solar collection efficiency. However, developing cost-effective and facilely synthesizable composite PCMs with improved efficiency and stability for solar-thermal energy storage presents a significant challenge. In this study, we propose a camel-hump-like adsorption strategy utilizing ZIF nano-ribbons modulated ultra-light self-standing Na 4 Mn 9 O 18 film for the incorporation of PCMs. The Na 4 Mn 9 O 18 -connected hierarchical architecture enhances capture of photons and provides a rapid pathway for phonon transport. Notably, ZIF nano-ribbons exhibit a function analogous to camels' humps in terms of fat storage, enabling efficient accumulation and retention of solar energy. Upon a decrease in external environmental temperature, these nano-ribbons release the stored solar energy as heat via the phase change of PCMs. As a result, the phase change film exhibited a high solar-thermal energy storage efficiency of 92.5 ± 2.4 % and retained its superior thermal physical properties even after 300 cycling tests, highlighting its significant potential for application in solar-thermal-electric conversion and thermal management of lithium-ion batteries. This study introduces an innovative approach to enhancing both the efficiency and stability of solar-thermal energy storage materials.