Finnish company Stora Enso presents an impactful innovation that is expected to change the way electric vehicles are charged – by using batteries made from trees.
Stora Enso’s innovation, Lignode replaces the graphitic carbon in lithium-ion batteries with a bio-based alternative made from lignin, which is sourced from trees and is one of the biggest renewable sources of carbon. A by-product during the production of cellulose fibre, lignin is produced in millions of tonnes in Europe.
According to the company, the use of graphite is one of the main challenges of today’s lithium-ion batteries. Being a fossil carbon, which is either mined or made from other fossil-based materials, graphite has major environmental consequences.
Detailing lignin’s journey from a tree to a battery anode, Stora Enso explained that lignin is first extracted from wood during the production of cellulose fibre, and then refined into a fine carbon powder, which serves as an active material for the negative anode of the lithium-ion battery. The hard carbon powder is then used to produce electrode sheets and rolls. Finally, the hard carbon electrodes are combined with positive electrodes, separator, electrolyte, and other components into a lithium-ion battery.
Graphitic carbon, which is currently used in the lithium-ion battery, is a strictly layered material that can have slow charging times. Replacing it with readily available hard carbon from trees can deliver both technical and environmental benefits.
Unlike graphitic carbon, hard carbons have a disordered and open structure, which enables the anode to be charged and discharged more quickly. Lignode also performs better at lower temperatures, and is, therefore, less prone to safety risks in freezing temperatures. Additionally, lignin is extracted from trees sustainably sourced from certified European forests.
“It is a rational and scalable way to switch to a renewable resource that is available in Europe,” the company said.
Elaborating on the benefits, Stora Enso said, “Lignin is renewable, traceable and millions of tonnes are already being produced in Europe. The potential for further growth provides a golden opportunity for the fast-growing battery business to become more sustainable and more effective.”
Stora Enso’s Sunila Mill in Finland is the world’s biggest producer of lignin with an annual capacity of 50,000 tonnes. Beginning the pilot production of Lignode in July 2021, the company is now working towards commercial production, with an aim to create a European supply chain for the lithium-ion battery industry and shape the way electric vehicles are powered in future.
Image: Stora Enso
