ERI: High-Temperature Thermochemical Energy Storage Using Doped Calcium Manganites

About This Grant

This project is about creating a special type of material called doped calcium manganite (DCM) perovskite oxides, which could be used for high-temperature thermochemical energy storage (TCES). The main goal is to improve Concentrated Solar Power (CSP) technology, which produces electricity from sunlight. As the world faces increasing energy demands, more renewable energy solutions are being developed, including CSP. However, CSP has a challenge: it relies on sunlight, which is an intermittent energy source. This makes it hard to use CSP all the time. To solve this, scientists are working on ways to store heat energy so it can be used when the sun isn’t shining. One promising solution is TCES, which allows CSP plants to store heat at high temperatures and release it when needed. This project will focus on developing and testing DCM materials to create the best possible heat storage solution. It will also help students who work on the project improve their critical thinking and problem-solving skills, preparing them for future careers in STEM fields. Currently, CSP plants use molten salt-based heat energy storage systems, but their low decomposition temperatures (600 to 650°C) limit plant efficiency by capping the operating temperatures of the power generation cycle. TCES leverages the heat generated from a reversible chemical reaction that facilitates the reduction (charging step) and re-oxidation (discharging step) of metal oxides such as DCMs. Compared to sensible heat energy storage, TCES possesses a substantially higher energy density and a more extended storage period. In this project, DCMs will be synthesized using the solution combustion synthesis approach by co-doping both the Ca and Mn sites with suitable metal cations. The primary objective is to attain a TCES capacity of greater than 500 kJ/kg within the optimal temperature range of CSP systems (700 to 1200°C). The design of DCMs will emphasize achieving superior enthalpy of reduction, extent of redox reactions, and cyclability, directly contributing to the attainment of the maximum TCES capacity. Density Functional Theory (DFT) analysis will provide theoretical insights into the potential of DCMs concerning oxygen vacancy formation energy (OVFE). Detailed characterization of DCMs will allow correlating their physical and chemical attributes with their ability to facilitate the redox reactions in TCES. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.