High temperature NaCl-Al2O3 (50-50

High temperature NaCl-Al2O3 (50-50 wt-%) composite material for thermal energy storage with large phase change enthalpy of 252 J/g was fabricated at extraordinary low temperature by cold sintering process. The average particle size of Al2O3 under the observed conditions was in the range 0.0189–0.089 mm, much lower than the starting powder particles size, demonstrating CSP role in the densification of metal oxide supports with chloride salt in water as sintering agent. The composite has good chemical compatibility and stability at high temperature after 30 thermal cycles and holding it at 850°C for 24 h without leakage. The composite demonstrates high mechanical strength, and stable and preserved Al2O3 structure. The mass loss only occurs at a temperature above 850°C due to volatilization of the chloride salts. In comparison with other fabrication methods, present novel CSP approach demonstrates a new route to fabricate composite material for wide range temperature thermal energy storage and allow material integration to target specific properties for the desired application. The initial understanding of the parameter-structure-property is unveiled, providing fundamental guidance for performance improvement for wide temperature range TES material fabrication.