Enhanced thermal energy storage performance of hydrous salt phase change material via defective graphene

Structural modification of two-dimensional materials has a significant influence on performance. In this work, a novel preparation method is presented to get defective graphene and the as-obtained defective graphene shows great benefits for the thermal energy storage performance of phase change material (PCM). Based on the experimental results, we found the structure of few-layer graphene becomes weak at high temperatures (1200 °C) under the protection of N2, and then some micro-defects could be formated in the surface of graphene at a suitable thermal treatment schedule in air atmosphere. Owing to the unique nature of defective graphene, the PCM/defective graphene composite showed a higher thermal conductivity than barium hydroxide octahydrate (Ba(OH)2·8H2O) as the pure PCM. Scanning electron microscopy (SEM) and thermal cycling tests revealed that the defective graphene can be acted as the nucleating agent, which reduced the supercooling degree of Ba(OH)2·8H2O. Furthermore, thermal cycle stability tests showed the composite PCM had outstanding thermal cycling stability, and the defective graphene can also be acted as a kind of stabilizer. We showed the excellent application values of defective graphene in the PCM field for energy storage. This work is beneficial to the development of graphene and PCM composites.