Dutch battery startup LeydenJar’s silicon anode tech could pose a challenge to China

Battery materials startup LeydenJar^[1] has closed a €13 million ($15.2 million USD) round to scale up manufacturing of its silicon anode technology for an unnamed “leading U.S.-based consumer electronics company.”

The Netherlands-based startup will use the funding, along with a €10 million commitment from the U.S. customer, to build the first phase of its facility, PlantOne in Eindhoven, Netherlands, which will open in 2027. Investors Exantia and Invest-NL lead the round.

Today, a majority of the world’s lithium-ion batteries, and the graphite anodes within them, are made in China.

Silicon anodes could upend that relationship^[2] while also dramatically improving the performance of lithium-ion batteries. While slow-and-steady advancements have doubled their energy density over the past decade^[3], LeydenJar says its pure silicon anodes can give them a 50% boost over traditional graphite anodes.

Battery manufacturers have long known this, but silicon’s delicate nature has kept them from incorporating large amounts. Silicon tends to swell when storing lithium ions, and without some structure to support it, it will crumble quickly with successive charge cycles.

To compensate, silicon anode startups have devised various scaffolds to keep things from breaking down. LeydenJar uses plasma vapor deposition to grow spongy silicon columns on a thin sheet of copper. Those spongy columns can swell and shrink, filling the space between them when loaded with lithium. 

The company says the silicon structures enable faster charging and a lower carbon footprint. It can withstand over 450 charge cycles before losing more than 80% of its capacity, a figure that shows progress but falls short of the 1,000 cycles automakers typically shoot for.

And while EVs are on LeydenJar’s roadmap, the company is starting with consumer electronics, a path that competitor Sila^[4] followed to introduce its silicon anode material.

To get into EVs, LeydenJar has a long road ahead of it. Automakers typically require years of data before qualifying new batteries, and building large-scale factories to meet demand can take years to finance and complete. Still, nothing is settled in the battery industry, and if the company can prove its material can offer a step change in performance without sacrificing durability or manufacturability, it’ll find plenty of eager buyers.