Performance Evaluation of Polyvinylpyrrolidone‐Coated Composite Salt Porous Matrix CAU‐10‐LiCl‐PVP for Water Adsorption‐Driven Heat Transformation Applications

Adsorption heat transformation (AHT) is an energy‐efficient and eco‐friendly cooling and heating technology, which can greatly reduce the pollution caused by fossil fuels. Composite salt porous matrix (CSPM) materials are potential adsorbent candidates in the field of AHT. However, the water uptake capacity of CSPM materials tends to decrease with increasing numbers of water adsorption/desorption cycles, limiting their large‐scale industrial application. Therefore, enhancing the cyclic stability of CSPM materials is crucial. In this study, we synthesized a PVP‐coated porous matrix composite salt material, CAU‐10‐LiCl‐PVP. Results indicated that the coating effect of PVP increased the number of mesopores and macropores in the product, which in turn expedited the diffusion and transport of water vapor within the pores, leading to more rapid adsorption and desorption processes. As the PVP content increased, the cyclic stability of the coated samples initially enhanced and then declined. The sample with a PVP‐to‐CAU‐10 mass ratio of 0.15 exhibited the best cyclic stability, with only a 1% decrease in water uptake after 30 cycles, compared to a 12% decrease for CAU‐10‐LiCl. These findings demonstrate that the PVP coating strategy can significantly enhance the cyclic stability of CAU‐10‐LiCl.