INTERVIEW: Stora Enso to make sustainable graphite-free anode material

Finnish company Stora Enso plans to start production of a sustainable bio-based carbon material made from lignin in the next 2-3 years and which would be able to replace graphite in a battery cell's anode and help de-risk the global battery supply chain, SVP, Head of Lignode, Lauri Lehtonen, told S&P Global Commodity Insights.

As one of the largest forest owners in the world, the company's business model is based on turning biomass into value-added products in different streams of which batteries is a growing value stream that Stora Enso has been working on for almost 10 years, Lehtonen said in an interview.

"Electric vehicles require anode materials and these are made out of graphite... the reality is that an EV requires 10-15 times more anode materials in a battery than lithium, so there is huge demand for this graphite," he said.

"If we think of a typical EV, there is 50-100 kg of this anode material in each car, so demand for this material is going to be millions of tons per year in the next 10 years, so demand is growing really fast, almost too fast and solutions to supply raw material are too slow and not always sustainable," Lehtonen said.

He said the reality was that most graphite was currently and would be manufactured in Asia, and China in particular, meaning it was a risk factor for battery makers and OEMs that came with a number of supply challenges.

Renewable, sustainable material

As a solution to that, Stora Enso has been working on a regenerative approach using lignin, which is bio-based, readily scalable and grows back.

"Lignin is the second most abundant biomaterial on earth and in every tree there is 20%-30% of this lignin and what makes it wonderful is that it has a very high carbon content, which is similar to graphite, which has also a high carbon content to be conductive for batteries to work," Lehtonen said.

The company extracts the cellulose out of trees and lignin is left over in the process, which can then be upcycled to be used as energy biomass or turned into anode material to replace graphite. That would help the EV industry increase sustainability and reduce the upfront carbon footprint of a vehicle, of which half came from the battery, Lehtonen said.

"What we have here is using a renewable, sustainable material that grows back and the way it grows is that while it grows it is actually sequestering carbon out of the atmosphere and locking it into the lignin," he said.

"We are basically sequestering carbon into that battery by providing this material into it so we have a very sustainable approach to something that otherwise would be locked into Chinese supply that is either coming from synthetic or natural mined graphite."

Stora Enso has been running an industrial scale pilot plant in Sunila, Finland, for almost a year at one of its mill locations, which has been designed to go through qualification processes with the customers, such as battery makers and OEMs.

The company is carrying out several dialogs with customers in different sectors around the world about possible offtake agreements, Lehtonen said.

The company is in the prefeasibility study phase in designing industrial-scale production and expects to make a decision on building the commercial plant in the near future, Lehtonen said.

He declined to give the planned capacity of the full-scale plant but said that it would be large enough to be "meaningful for the battery sector".

Stora Enso's studies are being carried out at the same location as the pilot plant, but the company is also considering scale-up opportunities at all its production locations or elsewhere.

The company also has a sustainable energy footprint and powers all plant using mainly the energy from the pulping/biomass process, and somewhat renewable water-based or nuclear-based power, while also generating excess energy production from biomass, Lehtonen said.