To store low-temperature heat below 120℃

novel expanded vermiculite/CaCl2 composite sorbents with four different salt contents were developed by impregnation methods. Morphologies records

sorption kinetics measurements

simultaneous thermal analyses (STA) and theoretical calculations of energy storage density were implemented on EV/CaCl2 sorbents

with EV and CaCl2·H2O as reference. Scanning electron microscope (SEM) imagines indicate that EV has huge pore volume with numerous layers

which contributes to relative high salt content without the worry issue of solution leakage. Simulative sorption experiment was conducted to identify threshold salt content that composite sorbents can hold without solution leakage. The sorption kinetics and equilibrium sorption capacity were obtained utilizing a constant temperature and humidity chamber

and the influence of salt content and relative humidity on sorption performance was analyzed. The quantitative analysis of total water uptake demonstrates that their sorption process consists of three different phases:physical adsorption

chemical adsorption and liquid-gas absorption of CaCl2 solution. Furthermore

water uptake

sorption heat and reaction temperature of each sorption process were obtained by analyzing the STA measurements. In general

EV/CaCl2 composite sorbent with salt content of 47.9% was selected as the optimal sorbent

whose water uptake

mass energy storage density and volumetric energy storage density can reach as high as 1.12 g·g-1

1.25 kW·h-1·kg-1

213.56 kW·h·m-3

respectively.