Adsorption characteristics and microstructure characterization of lithium bromide crystals

doi:10.19799/j.cnki.2095-4239.2025.0038

Abstract

Abstract:

The characterization of crystal morphology features is critical for revealing the solution–crystalline energy storage mechanism. The surface structure, pore distribution, and adsorption properties of crystals determine their adsorption and release efficiency during thermal energy storage. This study investigates the adsorption properties and microstructure features of both anhydrous and monohydrate lithium bromide (LiBr) crystals using advanced characterization techniques. This study provides detailed microscopic insights into the internal and external structures of LiBr crystals using a combination of vacuum vapor sorption analysis, scanning electron microscopy, and automatic surface area and pore size distribution measurements. The results demonstrate that under 90% relative humidity, anhydrous LiBr and monohydrate LiBr crystals exhibit adsorption of 3027.966 and 2322.909 mg/g, respectively. The LiBr crystals exhibit a rough surface microstructure characterized by etching craters, which serve as active dissolution sites and significantly affect the adsorption and desorption processes of the crystals. Under dry conditions (absence of liquid film), the specific surface areas of the micropores of anhydrous and monohydrate LiBr crystals are 1.1×10^-2m²/g and 8×10^-3m²/g, respectively, and the specific surface areas of the mesopores are 7.7×10^-2 m²/g and 8×10^-2m²/g, respectively. During water vapor absorption, LiBr crystals initially adsorb water vapor through surface pores. Once the adsorption reaches saturation, the crystals continue to absorb water vapor via dissolution. By adjusting the hydration state of LiBr crystals, their energy storage performance can be optimized while improving system stability. These findings provide both experimental and theoretical support for the optimization of solar thermal energy storage technology and the selection and design of materials for efficient thermal storage systems.

Key words: lithium bromide, crystal, adsorption, absorption, microstructure

CLC Number:

TM 911

Yonghan ZHAO, Gang WANG, Hui YANG. Adsorption characteristics and microstructure characterization of lithium bromide crystals[J]. Energy Storage Science and Technology, 2025, 14(7): 2707-2713.

Figures/Tables 7

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仪器	参数	规格	精度
气体蒸汽吸附仪	量程	1 μg/2000 mg	0.1 μg可选
	动态称重范围	10~100 mg	—
	分析位	2/4/8站	—
	蒸汽分压P/P₀控制范围	0.01%~99%	—

扫描电子显微镜	二次电子分辨率	0.7 nm	—
	二次电子分辨率	0.8 nm	—
	着陆电压	0.1～2 kW	—
	放大倍率	20~1000000倍	—

全自动比表面和孔径分布分析仪	孔隙度	3.5～5000 Å	—
全自动比表面和孔径分布分析仪	比表面积	>0.0005 m²/g	—