An increasingly electrified society has increased the demand for sustainable batteries. The challenge has been to find an environmentally friendly solution to today's lithium-ion batteries whose manufacturing process is associated with both environmental degradation and poor working conditions. According to forestry group Stora Enso, the solution to the problem could be lignin - a residual product from the wood and paper industry.
Lignin can be described as nature's own binding agent. It is the 'glue' that holds trees together, and one of the most important components of wood and the structure of plant cells. What makes lignin special is that it is the second largest source of renewable carbon available. This is where Stora Enso's innovation comes in. The company has developed a process where the hard carbon for battery anodes is made from refined lignin instead of fossil fuels. Lignin therefore has the potential to make the battery industry more sustainable and replace today's environmentally harmful alternatives.
Lignode - a renewable source
As sales of electric cars increase, so does the demand for environmentally friendly electric car batteries. Today, these are usually powered by lithium-ion batteries. Simply explained, these consist of three central parts, a cathode, an anode and a separator. The positive side, the cathode, consists of metals such as lithium and cobalt - substances associated with poor working conditions and environmental degradation. The negative side, the anode, consists of graphite, which is a fossil carbon that can be extracted in two ways today. Natural graphite is extracted from mines, while synthetic graphite is made from fossilised materials.
This is where Stora Enso and lignin come in. With its innovation, the company has made it possible to replace the fossil-based graphite in the anode part with hard carbon from lignin. The product, called Lignode, therefore has the potential to make the automotive industry more sustainable - Lignode is a renewable source that is utilised and extracted from the kraft pulp process. It then becomes a bio-based anode," says Otto Kivi, senior business development specialist at Stora Enso.
Pilot plant and co-operation with Polestar
Since 2015, Sunila Mill in southern Finland has been producing industrial lignin. It produces 50 000 tonnes annually, making it the largest lignin extraction plant in the world. To drive innovation and research forward, Sunila Mill has also been equipped with a pilot plant. It is in this plant that the lignin undergoes a transformation into hard coal, demonstrating Stora Enso's commitment to being at the forefront of sustainable technological development.
- The development is progressing and we are currently collaborating with some of Scandinavia's battery developers such as Northvolt and Beyonder to bring the batteries to commercial production. It is very exciting to work with innovative companies that also have sustainability in focus. Earlier this year, we also started a partnership with Volvo's Polestar, which aims to create a climate-neutral car by 2030," says Otto Kivi, who continues:
- Over 90 per cent of the anode is currently produced in China, and there is no direct production of batteries in Europe. With Lignode batteries, we will be able to offer a European supply chain in the future.
Learn more about Stora Enso's bio-based alternative Lignode at Subcontractor InnoDex during Elmia Subcontractor 14-16 November.
Subcontractor InnoDex is the arena for all the industry's product developers, engineers and designers - an extraordinary arena of knowledge and inspiration, with exhibitions and lectures on new materials, innovative technologies and creative processes.