Preparation And Properties Of Expanded Dickite Based Composite Phase Change Energy Storage Materials

With the development of human society,the problem of energy shortage is increasingly exposed.People begin to look for clean and recyclable energy.At the same time,they are also exploring energy storage technologies and materials.Phase change energy storage materials have been widely studied by researchers because of its high thermal energy density and high heat transfer efficiency.However,phase change materials have many problems such as easy leakage,low thermal conductivity and so on.Loading with porous materials is an effective means to solve this problem.In this paper,expanded dickite is selected as the carrier material,and polyethylene glycol,n-decanoic acid and disodium hydrogen phosphate dodecahydrate are used as phase change materials to prepare a variety of composite phase storage materials,so as to explore the feasibility of expanded dickite as the carrier of phase change materials.It is found that expanded dickite with porous structure was prepared through the urea intercalation and the calcination of dickite-urea intercalation compound with KCl O₃.By modulating the amount of KCl O₃,two kinds of expanded dickite with different expansion degrees of dickite layers were obtained.The expanded dickite with full layer expansion possesses a high polyethylene glycol load rate of 64.7%,a high latent heat of 98.22 J g^-1 and good thermal cycle stability.What’s more,the undercooling of phase change is reduced by 2.1℃,the thermal conductivity is increased by 26.2%,and the response speed of composite phase change material to temperature is improved.Expanded dickite can also be used as the carrier of n-decanoic acid,reaching a loading rate of 60%.N-decanoic acid is adsorbed and evenly distributed in the pores of expanded dickite through physical combination.N-decanoic acid has good compatibility with dickite.The phase change temperature of expanded dickite/n-decanoic acid composite phase change material can reach 31.64℃and the latent heat can reach 74.33 J g^-1.After 30 heat absorption/release cycles,the latent heat of the composite phase change material is only reduced by 1.81%.Expanded dickite also has good compatibility with disodium hydrogen phosphate dodecahydrate inorganic phase change material,which can reach 70%load rate in expanded dickite.Expanded dickite carrier can inhibit the leakage of phase change materials and improve the thermal conductivity of composite phase change materials.These advantages of expanded dickite make it an important carrier of novel phase change materials.