Experimental Research on the Preparation of K₂CO₃/Expanded Vermiculite Composite Energy Storage Material

Thermochemical adsorption energy storage is a potential energy utilization technology. Among these technologies, the composite energy storage material prepared by K₂CO₃ and expanded vermiculite (EVM) shows excellent performance. In this paper, the influence of the preparation process using the impregnation method and vacuum impregnation method on K₂CO₃/EVM composite material is studied. The preparation plan is further optimized with the solution concentration and the expanded vermiculite particle size as variables. In the experiment, mercury intrusion porosimetry (MIP) is used to measure the porosity and other parameters. Additionally, with the help of scanning electron microscopy (SEM), the morphological characteristics of the materials are obtained from a microscopic point of view. The effects of different preparation parameters are evaluated by comparing the experimental results. The results show that the K₂CO₃ specific gravity of the composite material increases with the increase of the vacuum degree, up to 70.440 wt.% (the vacuum degree is 6.7 kPa). Expanded vermiculite with a large particle size (3~6 mm) can carry more K₂CO₃, and content per cubic centimeter of K₂CO₃ can be as high as 0.466 g.