LeydenJar Technologies is a Dutch start-up on a mission to make lithium-ion batteries last longer. Batteries are playing an important role in the transition to a clean energy future, and with higher energy density they will further unlock growth for a range of industries.

Christian Rood

Replacing the graphite inside them with pure silicon, says LeydenJar co-founder and CEO Christian Rood, could be the key to longer-range electric vehicles, electric flying and residential storage.

When did you first become interested in battery technologies?

I started at ABN AMRO Bank as an investment banker, and then in 2009 I started my own boutique venture advising companies. It was then that I grew interested in clean-tech. That was an area where I could feel some purpose.

I wanted to do something that had an impact, so I started working on all sorts of clean-tech technologies and trying to get to market. That gave me the chance to look at the technologies that were being developed by inventors in research institutes, and then I saw this one.

What exactly was that technology?

It was a flexible solar panel technology developed by the Netherlands Organisation for Applied Scientific Research (TNO) that was not very successful in solar cell application, but the original inventor discovered it had a lot of potential for application in batteries. I fell in love with it and grabbed the opportunity with my co-founder to build a business out of it. The research institute didn't have a battery focus, so there was an opportunity to get some money in and build the right capabilities to make it a success.

Battery cells are everywhere, but we desperately need a technology that can get more energy in them. Not just for our iPhones, but for a range of industries: to get electric vehicles that have a longer range, and to enable new clean industries such as electric flying.

"We're designing, building and operating a new tool that will allow us to produce much more material at an affordable cost and with a low carbon footprint."

There is a huge market for batteries with higher energy density. LeydenJar says it can do that by swapping the graphite in batteries with silicon. How does that work?

Silicon as an anode can host 10 times more lithium ions. Nobody really 'invented' that – the whole battery industry is looking at silicon. But what is unique in what we are doing is we use a totally different production technology. And with it, we can produce a 100% silicon anode.

People have tried all over, and they never succeeded, because silicon has one big challenge: it swells if lithium ions enter it – it expands up to 300% – and just cracks if you charge it. In our case, it remains mechanically stable, leading to 70% higher energy density. In an industry that is currently able to improve energy densities by 3–5% per year, that is enormous.

How do you see that being scaled up in the future?

The holy grail is to be able to store energy you generate yourself at home. But most people don't have the space for a container of battery cells, so this is where increasing energy density is important, and you want it to be affordable.

For that you need back-end performance, but also industrialisation. In Eindhoven, we can produce rolls of this silicon nano material, and these rolls can be directly used by a battery-maker to make the whole cell.

But it's not happening fast enough, and we don't control the quality yet. But with our latest funding round we can take the step to fully industrial-based production. So we're designing, building and operating a new tool that will allow us to produce much more material at an affordable cost and with a low carbon footprint.

Are you worried about other battery technologies such as solid state batteries?

No – I see this as an opportunity. If you think about solid state batteries, the key thing is, it is solid electrolyte, and solid electrolyte primarily has a safety advantage. But what some of these companies do is they combine it with new anode or cathode material, such as lithium metal, and that can also lead to a very high energy density.

Now, if you look at our silicon anode, the energy density that it can achieve is pretty similar to solid state batteries, but it does not have some of the problems that are associated with lithium metal. There are more and more well-known research institutes and battery companies that are considering pure silicon anodes, in combination with solid electrolyte. We have already shown that it works very well with our silicon anode.

"Battery cells are everywhere, but we desperately need a technology that can get more energy in them".

Finally, what lessons have you learned as a leader getting into this exciting sector?

In the beginning, I was pretty naive – as most entrepreneurs are. Can you imagine – a former banker starting a battery technology company in the Netherlands, and working on silicon anode material? We did not have our own battery lab, so we were just a lean company working with some research institutes.

But I learned that that was a big advantage. A lot of battery technology is being innovated by technical people, but these technical people have a lot of dogma on how batteries should work and how they should be produced. So having the ability to look at this from a clean slate, and being open to new possibilities, really has allowed us to impact this industry a lot.

The additional quality that I bring is understanding how to fund a new business. If you have to learn how to raise capital for deep tech as a technical person, that's quite difficult. With my background in finance it is much easier. So understanding capital markets and investors, communicating with them, having a strategy that is in line with how capital markets look at big tech – that is crucial for growing a company like this.

For others trying to break into this space, it is important to hire in a mix of people. Not just technical people but people that have more experience on the business development and investment side of things. This is crucial in order to grow at scale.