Enhanced heat storage performance of CaCl 2 ·6H 2 O using BN nanosheet as an additive

Inorganic hydrated salt calcium chloride hexahydrate (CaCl 2 ·6H 2 O) has a broad application prospect in the field of phase change energy storage due to its own characteristics. However, it has some problems such as large supercooling and serious phase separation, which limit its practical application. In this paper, boron nitride nanosheets (BNNSs) were applied in the CaCl 2 ·6H 2 O system. It was found that the heterogeneous nucleation of CaCl 2 ·6H 2 O can take place on the surface of BNNS. BNNS can solve the supercooling and heat transfer problems of CaCl 2 ·6H 2 O effectively. At the same time, the addition of an appropriate amount of BNNSs can improve the stability of phase change composites. Compared with pure CaCl 2 ·6H 2 O (supercooling was 22.06 °C and thermal conductivity was 0.382 W·m −1 ·K −1 ), the supercooling of CaCl 2 ·6H 2 O/1 wt% BNNS composite was only 3.89 °C and the thermal conductivity was 3.918 W·m −1 ·K −1 . CaCl 2 ·6H 2 O/0.5 wt% BNNS composite has good cycling stability. This study has scientific significance for the development and application of BNNSs in the field of phase change energy storage.