储能科学与技术2025，Vol.14Issue(12)：4470-4482,13.DOI:10.19799/j.cnki.2095-4239.2025.0397
草酸钙基多孔复合热化学储热材料制备及其储热性能研究
Preparation and thermal performance of calcium oxalate-based porous composite thermochemical heat storage materials
摘要
Abstract
The reversible reaction of calcium oxalate monohydrate(CaC2O4·H2O)exhibits a high reaction enthalpy,making it a promising candidate for medium-to low-temperature heat storage.However,the mismatch between chemical reaction rates and heat and mass transfer significantly limits its practical application.In this study,CaC2O4·H2O was incorporated into porous matrices—expanded graphite(EG),expanded vermiculite(EV),and diatomite(DM)—to enhance thermal performance.Composite thermochemical heat storage materials(EG-CaC2O4·H2O,EV-CaC2O4·H2O,and DM-CaC2O4·H2O)were prepared via ethanol dispersion and vacuum impregnation.Their microstructure and thermal properties were systematically characterized using scanning electron microscopy,energy-dispersive X-ray spectroscopy,differential scanning calorimetry,and simultaneous thermal analysis.The study specifically evaluates the influence of porous matrices on the thermochemical reaction kinetics and physicochemical properties of CaC2O4·H2O.The EG-CaC2O4·H2O composite exhibited superior overall performance,achieving an encapsulation efficiency of 83.2%.Its thermal decomposition temperature decreased by 35℃to 164℃compared to pure CaC2O4·H2O,while thermal conductivity increased by 173%to 0.648 W/(m·K).The EV-and DM-based composites showed encapsulation efficiencies of 61.2%and 76.1%,respectively,with decomposition temperatures reduced by 20℃and 25℃relative to the pure material.Thermal conductivity improvements reached 16%for EV and 82%for DM composites.All composites retained over 95%of their original heat storage density after 100 charge-discharge cycles,demonstrating excellent cyclic stability.The hierarchical porous structure of EG facilitates rapid heat and mass transfer and effectively mitigates particle agglomeration during hydration and dehydration.These findings provide valuable insights for the design of medium-to low-temperature thermochemical heat storage materials with enhanced performance.关键词
一水合草酸钙/热化学储热/多孔材料/热导率/循环稳定性Key words
CaC2O4·H2O/thermochemical heat storage/porous material/thermal conductivity/cycling stability分类
通用工业技术引用本文复制引用
CHENG Xin,LI Yuanyuan,YANG Guang,ZHANG Shuailong,CHENG Xiaomin..草酸钙基多孔复合热化学储热材料制备及其储热性能研究[J].储能科学与技术,2025,14(12):4470-4482,13.基金项目
湖北省揭榜科技项目(2024BEB012,2024BEB022) （2024BEB012,2024BEB022）
湖北省科技创新人才计划(2023DJC089). （2023DJC089）
