In order to obtain an efficient phase change material (PCM), emerging montmorillonite/stearic acid (Mt/SA) microcapsules containing SA core with Mt shell were designed and prepared via self-assembly of Mt in the SA emulsion. The Mt/SA microcapsules were coated with Si02 from the hydrolysis and polycondensation of TEOS to enhance the structure stability. The microstructure, thermal properties and reliability of Mt/SA microcapsules were investigated via scanning electron microscopy (SEM) and differential scanning calorimetry (DSC). The Mt/SA microcapsules presented sphere-like particles and had a size distribution from 10 to 30 pm. The freezing latent heat of the Mt/SA microcapsules was 118 J/g at 52.3 degrees C. The energy storage rate of the Mt/SA microcapsules was faster compared to SA. The Mt/SA microcapsules had excellent structural stability, high energy storage capacity and stable energy storage and release performances. The energy storage performances of the Mt/SA microcapsules were superior to the Mt/SA composites prepared via vacuum impregnation. Excellent energy storage reliability and capability of the Mt/SA microcapsules have advantages for solar energy storage fields. (C) 2017 Elsevier B.V. All rights reserved.