Copper-oxide spinel absorber coatings for high-temperature concentrated solar power systems

Concentrated Solar Power (CSP), a promising renewable energy technology, involves methods to concentrate the sun's energy onto receiver systems that generate steam, activate turbines, and consequently generate electrical power. To ensure CSP technologies remain cost-competitive, absorber coatings on CSP receiver systems require performance enhancements for increasing solar-thermal energy conversion efficiency. In this work, black metal-oxide nanoparticles comprising copper-cobalt oxides (Cu_xCo_3−xO₄) and copper-manganese oxides (Cu_xMn_3−xO₄) are synthesized for solar absorptive potential by hydrothermal syntheses – selected for low-cost, energy-efficient fabrication capable for bulk manufacturability. The material is deposited onto high-temperature, durable Inconel substrates by a flexible spray-coating method, and characterization is performed by Scanning Electron Microscopy (SEM), Energy-Dispersive X-Ray Spectroscopy (EDS), and X-Ray Powder Diffraction (XRD) analyses, as well as measurements to gauge thermal performance. High temperature stability of a model solar receiver surface using these synthesized materials are assessed by comparing spectral reflectance and a figure-of-merit efficiency metric before and after high temperature exposure beyond 1000 h. To extend spectrally-selective absorbance capability, the coating surfaces are geometrically-textured using sacrificial polymer beads that are jointly implemented in the spray-coating process. This study ultimately showcases materials produced with high figure-of-merit conversion efficiency, demonstrating solar absorber coatings capable of interfacing with next-generation CSP receiver systems.