Ceramic composite heat storage materials were prepared by mixed sintering method with binary carbonates (Li2CO3-K2CO3

BC

62:38

mole ratio) and ternary carbonates (K2CO3-Li2CO3-Na2CO3

TC

1:2:1

mole ratio) as phase change materials

and with magnesium oxide as the matrix material. The melting point of binary and ternary carbonates composites (BCC

TCC) are 465.1℃ and 386.4℃ respectively

which is similar to the corresponding mixed carbonates. Composite heat storage materials maintain a high specific heat value within the highest using temperature (800℃)

and the latent heat is more than 150 J/g. Based on the characterization analysis of XRD and SEM

two kinds of composite heat storage materials have good chemical stability

and the matrix material can well support the phase change material. The thermal properties of the composite heat storage materials don't change significantly and have good thermal cycling stability after 50 thermal cycles.