溴化锂晶体吸附特征和微观结构表征研究

doi:10.19799/j.cnki.2095-4239.2025.0038

摘要/Abstract

摘要：

晶体形貌特征的表征是揭示溶液结晶蓄能机理的关键。晶体的表面结构、孔隙分布及吸附特性决定了晶体在热能储存过程中的吸附和释放效率。本工作采用多站重量法全功能蒸汽吸附仪、扫描电子显微镜和全自动比表面和孔径分布分析仪，从微观角度表征了无水和一水溴化锂晶体的吸附特征以及内外微观形貌。结果表明，溴化锂晶体在溶解过程中存在吸附现象，当相对湿度为90%时，无水溴化锂吸与一水溴化锂晶体的最大饱和吸附量分别为3027.966 mg/g和2322.909 mg/g；溴化锂晶体表面显微结构粗糙，存在的蚀坑成为溶解台阶，影响晶体吸附和解吸的过程；当晶体表面无液膜存在时，无水溴化锂与一水溴化锂晶体的微孔外比表面积分别为1.1×10^-2 m²/g和8×10^-3 m²/g，介孔比表面积分别为7.7×10^-2 m²/g和8×10^-2 m²/g，在吸收和传递水蒸气时溴化锂晶体先通过表面的孔隙吸附水蒸气，当吸附达到饱和后，晶体再通过溶解过程吸收水蒸气。通过调节溴化锂晶体的水合状态，可优化其储能性能，并增强系统稳定性，为太阳能热能储存技术的优化及高效储热系统的材料选择与设计提供实验与理论支持。

关键词: 溴化锂, 晶体, 吸附, 吸收, 显微结构

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

中图分类号:

TM 911

赵泳涵, 王刚, 杨晖. 溴化锂晶体吸附特征和微观结构表征研究[J]. 储能科学与技术, 2025, 14(7): 2707-2713.

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.

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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	—