Nanofabrication of Multi-Shells Hollow CuO Microspheres for an Enhanced Cyclic Redox Reaction in High-Temperature Thermochemical Heat Storage Applications

Thermochemical energy storage systems relying on the CuO/Cu₂O redox reaction offer a promising solution for decarbonizing high-temperature applications (around 1000 °C). However, the predominant challenge with this material is the occurrence of sintering, impeding cyclic operation and significantly reducing storage efficiency after multiple cycles, as documented in the literature. This study presents a straightforward one-pot synthesis process for hollow CuO microspheres to improve the cyclic performance of thermochemical heat storage systems based on the CuO/Cu₂O redox. A distinctive aspect of this work, compared to previous investigations, is the absence of any doping material in the final product, resulting in a remarkably high energy density of approximately 747 kJ/kg. The formation of multi-shelled hollow CuO microspheres was confirmed through Scanning Electron Microscopy (SEM) techniques. Furthermore, the synthesized material exhibited stable cyclic performance after 10 cycles, as demonstrated using the Simultaneous Thermal Analysis (STA) apparatus.