| About this Abstract |
| Meeting |
MS&T21: Materials Science & Technology
|
| Symposium
|
Energy Materials for Sustainable Development
|
| Presentation Title |
Magnesium-air Fuel Cell and MgO Electrolyzer |
| Author(s) |
Hongyi Sun, Armaghan Telgerafchi, Madison Rutherford, Gabriel Espinosa, Lucien Wallace, Adam C. Powell, Mahya Shahabi |
| On-Site Speaker (Planned) |
Mahya Shahabi |
| Abstract Scope |
A magnesium-air fuel cell (MAFC) concept delivers up to 3.5 W/cm² at 42% efficiency or 0.5 W/cm² at 80% efficiency. A low-melting molten salt electrolyte dissolves O²⁻ at cathodes and Mg²⁺ at anodes. Porous Ni or Ti cathodes maintain back pressure and create air bubbles down to the bottom of the cell, with a contact to the next Mg anode in the stack. Rising air bubbles stir away dissolved MgO, which either precipitates out and is filtered, or freezes out at the cell bottom. Salt and Mg melting points bound the operating temperature between 400°-620°C. Preliminary experiments show up to 73% of theoretical performance. Reactive cathode molten salt electrolysis with multiple-effect distillation reduces MgO back to Mg at 50-70% efficiency, leading to 40-55% round-trip efficiency, with zero direct emissions (cf. 40% for compressed or liquid H₂). Ceramic solid oxide membrane (SOM) anodes produce pure O₂. |