MnO2 decorated double-shell microencapsulated phase change materials for photothermal conversion and storage

Solar energy is considered as a renewable energy source, but it still exists imbalance between energy supply and energy consumption. Although phase change materials (PCMs) can supply an effective way to improve solar energy utilization efficiency with the help of their excellent energy storage capacity, their poor solar-thermal conversion performance significantly reduces energy storage capacity and seriously restricts their applications in solar energy utilization fields. Herein, this work innovatively prepared MnO2-decorated double-shell microencapsulated PCMs using electrochemical adsorption and redox methods to cover a second compact shell of MnO2 on the first polymeric shell, which integrate the advantages of organic and inorganic shell materials with multi-functions and broaden the wide-spread applications of PCMs. The MnO2-decorated double-shell endows the microencapsulated PCMs with multi-functions and broadens their wide-spread applications. The excellent electrochemical and optical performances of MnO2 shell provide the microencapsulated PCMs with a high lightto-heat conversion efficiency of 93 %, and also endow the composite PCMs with a specific capacitance of 364 F/ g. Meanwhile, phase change enthalpy of the microencapsulated PCMs is in the range of 133.56-152.71 J/g. These results confirm that the MnO2-decorated double-shell microencapsulated PCMs have a considerable potential in solar energy utilization and electrochemical fields.