Thermal conductivity of opal filled with a LiIO3 ionic conductor

The temperature dependences of the thermal conductivity of a synthetic opal and opal-based nano-composites prepared by introducing a LiIO₃ superionic conductor into pores of the opal matrix from an aqueous solution or melt are measured by the hot-wire technique in the temperature range 290–420 K. It is demonstrated that the thermal conductivity of pure opal increases with an increase in the diameter of the SiO₂ spheres forming a face-centered cubic lattice of an opal and is determined by the total thermal resistance of interfaces between the spheres. Filling of opal pores with the ionic conductor leads to an increase in the thermal conductivity. The behavior of the thermal conductivity and its magnitude in opal-based nanocomposites depend to a large extent on the method of filling the matrix pores.