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Amorphous electrode materials for rechargeable batteries

The Carlsberg Foundation’s Distinguished Associate Professor Fellowships

What

Present day rechargeable Li-ion batteries are built from electrodes, which are highly crystalline. This means, that the atoms in the materials are structured in a highly symmetrical manner. This project will investigate how disordered, so-called amorphous, materials function as electrodes in rechargeable batteries. Especially, the project will shed light on how ions (e.g. Li-ions) are stored in the disordered materials during battery charge and discharge. Here we will look at the atomic-scale mechanisms for how the ions enter and leave the disordered materials, and how it affects the battery performance.

Why

In our future energy system rechargeable batteries plays an essential role for both transportation and energy storage. This puts high requirements on price, safety and life time of the technology. Hence, completely new battery technologies need to be developed. Compared to their crystalline counterparts, amorphous materials often have significantly lower production costs. Thus, they hold the promise to lower battery prices significantly. Furthermore, several amorphous materials show high ion storage capacity - some even double that of their crystalline counter parts. However, to successfully develop stable cheap electrodes from amorphous materials enhanced knowledge about how these materials store ions and how their structure correlates with their electrochemical behavior is needed.

How

At the center of the project is our ability to "see" how the atomic structure of the disordered electrodes changes, while the battery is operating, i.e. during charge and discharge. This is achieved by using very intense X-ray radiation and specially designed battery test cells. With these tools we utilise the X-rays scattered from the electrode materials to construct movies of the structural changes. Furthermore, as the project deals with disordered materials, we will turn towards new methodologies for battery material characterisation such as spectroscopy, which we also aim to use while the battery is being operated. For the project, a PhD student and a post-doctoral researcher will work with several master students under the supervision of the project leader to ensure project synergy.

SSR

Li-ion batteries are being increasingly employed in large scale applications, such as power tools and electrical vehicles. In the future we are likely to find batteries at the core of our energy system both for storage of intermittent renewable energy and in systems for grid scale load leveling. This development will move us towards a fossil-fuel free society. However, the increased use of batteries poses problems both in terms of the combination of high price and relatively low life time of the present technology and the availability of lithium, which may be too low for the projected use. This project will investigate the fundamental science behind a new class of batteries, which will enable lower production price and look into utilising far more abundant Na-ions as the active ion.