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Electric vehicles and anode-free sodium-based batteries

26 Junio 2020

A full transition to electric in the automotive sector and its obstacles are what inspired Alessandra Accogli, winner in the Technology category at the Lamborghini Future FAB Awards and PhD from the Milan Polytechnic at the Surface and Electrochemical Engineering lab. Alessandra developed an innovative project regarding the use of anode-free sodium-based batteries. Let’s find out more about it.

How did the idea of “anode-free” sodium-based batteries come about?

The field of energy, in particular electrochemical energy and batteries, has always been my passion, and this idea was born from my curiosity: what are the current obstacles for a complete transition to electric in the automotive field? And above all, how can they be overcome? I’ve been looking for innovative solutions, using materials other than those currently used. The basic idea is to use sodium instead of lithium; materials that, although similar in chemical terms, actually behave differently, in addition to sodium being a much more accessible resource. Through a series of studies and research, I also thought to combine sodium with pyrite, so FeS – at the moment all the sulfur-based materials are gaining particular value in the field of batteries because they are very green and low cost – reducing the economic and especially the environmental impact of technology on our ecosystem. In addition, the elimination of the anode makes it possible to drastically increase the final energy density and consequently increase the range, which is one of the main limitations for the diffusion of electricity in the automotive industry, as well as increasing safety in the use of batteries by reducing the risk of explosions.

What are the advantages of using sodium, apart from the fact that it is more environmentally friendly?

In the technology I’ve proposed, the operating mechanism differs substantially from traditional lithium-ion batteries. In this case, in fact, sodium electrodeposition is involved and not the classic intercalation phenomenon, i.e. the phenomenon in which the ions enter into the materials that make up the battery electrodes, damaging their structure over the long term. So the device has a longer life, i.e. it can sustain a high number of cycles, and reach higher powers. All this results in a reduction in electronic waste, ensuring a lower environmental impact and greater sustainability.

What is the main challenge to be confronted to make its use possible?

For the complete diffusion of the device, it is necessary to develop materials that are stable and scalable at the industrial level. The main objective is to facilitate sodium deposition at the battery anode and minimize the formation of “dendrites”; these three-dimensional structures can progressively damage various components of the system, so the engineering of the surfaces is definitely a crucial point.