Interface chemistry and electrochemistry in magnesium-ion batteries

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Improved energy storage technologies are required for large-scale, stationary applications such as grid load leveling and energy storage for intermittent renewable electricity generation. Magnesium batteries are among the most compelling alternatives to lithium-ion batteries, with significant advantages in terms of safety, resource abundance, and possible higher capacities by virtue of the divalent magnesium ion. Magnesium batteries are far less explored than the technologically mature lithium-ion battery. Interest in this technology has increased as limits in lithium ion battery energy density are reached. In this research project, researchers will address key scientific challenges facing magnesium batteries and pave the way for new energy storage technologies. This fundamental research project will educate and provide research experiences to graduate and undergraduate students in the field of sustainable clean energy materials and manufacturing technology. The project will also foster a positive culture among graduate and undergraduate students that accepts, respects and tolerates differences of others. This research project investigates the anode-electrolyte and cathode-electrolyte interfaces, rather than the three components individually. The strategy is to view the combined three components as a system to provide additional insights about the interfaces to address two of the biggest problems for magnesium batteries: passivation of the anode and the dearth of high-energy cathodes. The project team has demonstrated a fluoride coating that functions as the first solid-electrolyte interphase layer to conduct magnesium ions, and the layer will be characterized in greater detail to understand and improve upon its electrochemical performance. The project will include the design of electrochemical protocols to measure the true cathode performance and standardize cathode testing across different laboratories. The analysis and characterization templates allow for rapid electrochemical screening of prospective materials and characterization with XRD and new in situ EXAFS techniques. The most promising magnesium cathode materials will be subjected to defect engineering strategies previously developed by the researchers for lithium-ion battery materials. Some of these tools include cation or anion doping, introducing vacancies through controlled annealing, modification of surface chemistry with ion exchange, and synthesizing amorphous materials.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.