Can graphitic carbon in batteries be replaced by a more sustainable material? One possibility is lignin, a major component of trees that can be obtained as a byproduct of pulp production.
Sustainability is becoming a top priority for the automotive industry in Europe. More than half of the CO2 footprint in the production of electric vehicles comes from the battery. The graphite in the anodes is the second largest contributor to CO2 emissions from battery cell components. Alternative anode materials with low carbon emissions can help: Lignin-based anodes have the potential to be a neutral or even negative CO2 emission solution for battery manufacturers thanks to the renewable raw material wood.
All of the raw materials used in batteries currently have to be imported - a major challenge for Europe. The raw materials required raise questions from a competitive, environmental, and sustainability point of view, as well as geopolitical aspects.
One of the key components in batteries is the anode. It is estimated that in 2030 the average anode consumption per electric car will be 50 to 80 kg. Europe is currently completely dependent on the supply of fossil-based graphite carbon from Asia. Carbon is needed in the battery anodes to absorb the lithium ions during the charging and discharging phases.
»Stora Enso can supply active anode materials for lithium-ion batteries based on renewable lignin from trees. The use of lignin does not increase the number of trees harvested, but generates additional value from them. Lignode from Stora Enso offers a sustainable, cost-effective, high-performance and local supply chain solution for anode materials in Europe,« explains Lauri Lehtonen, Head of Lignode Business at Stora Enso.
Trees are made up of 20 to 30% lignin, which acts as a binder and gives wood its stiffness and resistance to decay. It is one of the largest renewable sources of carbon anywhere. As a side stream in pulp production, lignin has traditionally been burned for energy.
Today, Stora Enso extracts lignin at its Sunila pulp mill in Finland to convert it into hard carbon for batteries. The trees used to extract this lignin come from certified forests in Scandinavia and the Baltic States.
The Sunila mill in Finland is the largest kraft lignin producer in the world. Lignin has been produced here since 2015, and the pilot plant for lignode started operations at the same mill site in 2021. Stora Enso is currently conducting a feasibility study to evaluate the first industrial site for local supply of fossil-free hard carbon in Europe. To serve the fast-growing anode materials market, Stora Enso is exploring strategic partnerships to accelerate the scaling and commercialization of Lignode and drive the reduction of global dependencies in the European battery supply chain.