Sustainable Breakthrough in Manganese Oxide Thermochemical Energy Storage: Advancing Efficient Solar Utilization and Clean Energy Development

Solar power generation systems, recognized for their high energy quality and environmental benefits, require efficient energy storage to ensure stable grid integration and reduce reliance on fossil fuels. Thermochemical energy storage (TCS) using metal oxides, such as the Mn2O3/Mn3O4 redox system, offers advantages like high energy density, wide temperature range, and stability, making it ideal for solar power applications. This study investigates Mn3O4 and Mn2O3 as initial reactants, analyzing reaction temperature range, rate, conversion efficiency, and cyclic performance via synchronous thermal analysis. Microstructural characterization was performed using XRD, SEM, BET, XPS, nanoparticle size, and zeta potential measurements. The results show that Mn3O4 reversibly converts to Mn2O3 with over 100% conversion efficiency over five cycles with 3.3% weight loss, indicating stable performance. Mn3O4 oxidation follows Arrhenius' Law below 700 degrees C but deviates at higher temperatures. The oxidation mechanism function is G(alpha) = alpha and f(alpha) = 1, with an activation energy of 20.47 kJ/mol and a pre-exponential factor of 0.268/s. Mn2O3 synthesized via ammonia precipitation exhibits reversible redox behavior with 3.3% weight loss but samples from low-concentration precursors show poor cyclic performance. The reduction reaction of Mn2O3 has an activation energy of 249.87 kJ/mol. By investigating the Mn2O3/Mn3O4 redox system for TCS, this study advances its practical integration into solar thermal power systems and offers critical guidance for developing scalable, low-carbon energy storage technologies. These findings can support Sustainable Development Goals (SDGs) by advancing renewable energy storage technologies, reducing carbon emissions, and promoting the integration of solar power into sustainable energy grids.