GO INTO BATTERY TECHNOLOGY— FROM NORTHEASTERN TO MILAN

CHRISTOPHER OWEN (FS 2020/21, NORTHEASTERN UNIVERSITY)

Being a researcher in the energy sector is truly fascinating. Recent years have witnessed enormous technological progress in the development of renewable energy to address the climate crisis. This has brought new opportunities to emerging technologies for the betterment of mankind.

The future of clean energy and electric vehicles depends on our ability to store and release energy efficiently and at a reasonable cost. During the past five years, I had the opportunity to work in the field of battery technology. One company I worked for, Form Energy, is commercialising a long-duration battery for the grid, meaning it provides energy for extended time periods at a reasonable cost. The chemistry of the battery is iron-air. It turns iron to rust during discharge and then rust to iron on charge. This experience inspired my decision to pursue further studies at Columbia’s Electrochemical Energy Center.

Last year, thanks to the support from the Foundation, I moved to Milan and had the opportunity to work with Professor Marcel Di Vece at the University of Milan for a project on energy storage for five months. Hydrogen fuel is a sustainable alternative to fossil fuels and a vital tool for decarbonization. A limiting factor for enabling hydrogen as a fuel is that it exists as an explosive gas at room temperature. As a result, it is extremely difficult and expensive to store and transport. Although batteries are the dominant fuels used in the electric vehicle industry, hydrogen still plays a crucial role in decarbonisation in industries such as steel production. Low-cost materials that can store hydrogen densely and safely are critical to building a global hydrogen economy.

Magnesium is a desirable host material as the lightest weight metal with a high affinity for storing hydrogen. The difficulty with using magnesium is the high heat (300 degrees Celsius) required to release the hydrogen after storage. Plus, magnesium readily oxidises when exposed to air, hindering its storage capabilities. When we began the project, we hoped to prove that we could protect magnesium particles from oxidation and hydrogenate them. We succeeded on that front with an unexpected and exciting result: light-induced hydrogen release at room temperature. Magnesium hydrogen storage and release at room temperature would be a game-changer for hydrogen fuels.

Palladium is a metal commonly used for its catalytic properties; it can spontaneously separate molecular hydrogen into protons and transport them by diffusion through the metal. Silicon nitride is a material that resists oxidation. In our project, we used a large machine known as a “gas aggregation nanocluster source” to spray magnesium and silicon nitride onto a palladium surface. By depositing magnesium nanoparticles on top of palladium and then coating them with silicon nitride, we designed a system that allowed us to shuttle protons through a palladium layer to magnesium particles protected from the ambient air.

The next phase of the research was the material characterisation. We hoped to form a magnesium hydride. To attempt to hydrogenate our deposited samples, I used a small chamber pressurised with gaseous hydrogen. To assess whether we had achieved successful hydrogen insertion, we used a characterization technique called “UV-Vis Spectrophotometry.” The technique involves exposing a material to light at different wavelengths and measuring its transparency. If more light could penetrate the material after hydrogenation, that would suggest the formation of magnesium hydride. In our project, after hydrogenating the samples, we saw an initial increase in transparency that de - creased the longer the sample was exposed to specific wavelengths of light. Hydrogen was being released from the magnesium! That usually only happens above 300 degrees Celsius; this was at room temperature. If scaled up and used in practice, this technology could bring massive energy savings.

Our work titled “Photo-stimulated hydrogen desorption from magnesium nanoparticles” was published in the International Journal of Hydrogen Energy. This is my first-ever publication in a scientific journal and one of the most rewarding experiences of my life. I formed lifelong friendships, made incredible memories travelling across Italy, and expanded my knowledge of energy storage materials during the exchange programme. I am tremendously grateful to the Fung Foundation for supporting my experience in Milan.