Molten (solar) salt is currently the most used storage material in large concentrated solar power systems, particularly in combination with two-tank storage systems. The storage medium for a thermal energy storage system typically makes up the largest percentage of the investment costs for the sub-system. The high material cost is a strong incentive to find alternative storage materials with equal or better thermal energy storage properties to reduce both the cost of storage and the levelized cost of electricity. This study aimed to design and test a structured material packing for thermal energy storage applications. The material design focused on developing a cheap ceramic composite material and testing and measuring the material's thermal and structural properties. The geometric brick design for the structured packing was also a key objective for this project. The composite ceramic material development started with selecting and assessing suitable ceramic materials. The selected materials include naturally occurring clay and industrial waste materials such as fly ash and blast furnace slags. The selected materials were sourced, prepared as sample cubes then fired to achieve vitrification. The geometric design of the structured packing brick focused on developing a high surface area (for good heat transfer) and low voidage (for a high thermal mass). A theoretical 1-dimensional numerical study on several created concepts was conducted to assess the thermal performance of the proposed brick geometry.