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FOCUS 74: The Driving Force Behind Efficient Batteries

Founding Director and Chief Technology Officer of KVI Holdings, Rachid Yazami, talks about laying the groundwork for the future of electromobility and lithium-ion batteries. 

You have dedicated your career to lithium-ion batteries. On a personal and professional level, what is the significant impact of harnessing this technology?  

I started working on batteries from a materials science and electrochemistry perspective in 1978 following graduation in engineering from the Grenoble Institute of Technology. Since then, I have dedicated my career essentially to battery research. I found it an overly exciting field of activity because it is multidisciplinary by nature, covering a wide range of scientific areas such quantum mechanics, condensed matter physics, crystal chemistry, electrochemistry, and organic and inorganic materials.  

The other motivation at that time was to address the oil crisis of the 70's to move from fossil to clean and sustainable energy resources, which batteries can help achieve. Compared to other chemistries lithium batteries show much higher performances in terms of energy storage. However, in the 70’s only disposal lithium batteries were available in the market. It was tenting and challenging to develop the rechargeable version of the lithium-based chemistry. Unlike disposal batteries where the discharge process is irreversible, rechargeable batteries require high efficiency (>99.9%) in reversible electrode reaction, which is exceedingly rare in nature. Double difficulty comes for the fact that both the positive and the negative electrodes must be highly reversible.  

My PhD project was to develop a positive electrode (cathode) based on graphite intercalated with some metal chlorides for rechargeable lithium batteries. During the battery discharge lithium ions will intercalate in the graphite-based material and react with the metal chloride. Perhaps as part of a personal curiosity I asked myself whether lithium can intercalate into graphite without a metal chloride. After several unsuccessful trials I finally was lucky enough to combine lithium and graphite in a reversible way and that was my biggest achievement. I was only 26 years old! The graphite anode was born, and it is widely used as the anode in today’s rechargeable lithium batteries. 

Electromobility  is changing the automotive world. Where do you see the role of smart batteries and how will it evolve? 

There are four major requirements for a battery to be used to power an electric vehicle 1) the driving range, which should be higher than 500 km per charge, 2) the charging time, which should fall below 20 min, 3) the lifespan which should exceed 8 years or 200,000km and 4) safety, which cannot be compromised. At KVI, we have addressed all these aspects but where we believe we make the biggest impact is dramatically reducing the charging time to below 20 minutes for high energy batteries and to 6 minutes for high-powered batteries without compromising life and safety. 

We have challenged the over-a-century long charging method based on applying constant current and constant voltages. Our non-linear voltammetry-based protocol is a natural charging where the battery responds to an increase in voltage as it can without imposing any stress such as a constant current. With this we believe we will contribute to make electric vehicles more friendly and widely accepted for the future energy transition.        

 

 

^{Interview with Founding Director and Chief Technology Officer of KVI Holdings, Rachid Yazami, for FOCUS #74. To read more articles from this issue, download your digital copy here}