ThermoChemical Storage (TCS) involves the exploitation of the heat effects of reversible chemical reactions for the “storage” of solar heat. Among gas-solid reactions proposed for such an approach the utilization of a pair of redox reactions involving multivalent solid oxides has several inherent advantages that make it attractive for large-scale deployment.The new concept introduced in the current proposal is instead of using packed or fluidized beds of the redox material as the heat storage medium, to employ monolithic structures like honeycombs or foams, made entirely or partially from the redox oxide materials. The proposal stems from and capitalizes on a number of ideas, concepts and achievements materialized in previous co-operations among the current consortium members:- The successful development, qualification and demonstration of honeycombs made of advanced ceramics to operate as effective volumetric solar thermal collectors/heat exchangers in Solar Thermal Power Plants.- The successful demonstration and scale-up to the 100-kW of “structured” honeycomb reactors involving coating of mixed-iron-oxides-based redox materials on advanced ceramic supports for cyclic solar hydrogen production.- The capability of several multivalent oxide-based redox systems to be used in thermochemical storage cycles in order to store and release heat in Concentrated Solar Power (CSP) plants.The proposed concept combines the demonstrated technologies of ceramic volumetric receivers and structured solar reactors and promotes them one step further to the development of an integrated receiver/reactor/heat exchanger configuration with enhanced heat storage characteristics, through a series of innovations to be implemented concerning new reactor/heat exchanger designs, enhanced incorporation of redox materials in the reactor’s structure, improved redox material compositions and utilization of industrial wastes as raw materials for the oxide redox systems synthesis.