A nanocomposite phase change thermal energy storage material was prepared by intercalating stearic acid into the nano-layers of modified bentonite in liquid media. XRD patterns showed that the intergallery distance of the nanocomposite material was larger than that of modified bentonite owing to intercalating of stearic acid. The phase change temperature of the nanocomposite phase change material was different from that of stearic acid

and its phase change latent heat was equivalent to the calculated value based on the mass ratio of stearic acid in the composite. The experimental results of thermal energy storage and release indicated that the heat transfer rate of the nanocomposite material was obviously higher than that of stearic acid. After the nanocomposite experienced 1500 times cooling-heating cyclic test

its phase change temperature and latent heat showed little change

which suggested that the stearic acid/bentonite nanocomposite phase change material exhibited good stability of structure and properties. This method of intercalating organic phase change material into the nano-layers of bentonite provides a new route to prepare phase change materials with high performances.