The transition to renewable energy is driving strong demand for safe, affordable and scalable energy storage. Today’s battery technologies rely heavily on lithium-ion systems, which depend on scarce and often imported raw materials. This raises concerns around cost, supply security and environmental impact. Researchers at Fraunhofer IKTS in Germany are developing an alternative: sodium-ion batteries made partly from lignin, a biobased by-product of the wood industry.

Lignin is a natural polymer that gives wood its rigidity. In the paper and pulp industry, it is usually treated as waste and burned for energy. The ThüNaBsE project (Thuringia Sodium-Ion Battery for Scalable Energy Storage) aims to use this material in a more valuable way. The project brings together Fraunhofer IKTS, Friedrich Schiller University Jena and several industrial partners, supported by regional and European funding.

Lignin-Based Hard Carbon for Battery Electrodes

Within the project, researchers convert lignin into hard carbon using thermal processes under inert conditions. They then use this material as the negative electrode in sodium-ion batteries. Lignin-based hard carbon shows a structure that allows sodium ions to be stored and released efficiently. It also offers good cycle stability and low production costs.

By using lignin, the team avoids critical metals such as lithium, cobalt and nickel. The researchers also work to reduce the use of fluorinated substances in electrodes and electrolytes. This approach improves both the environmental footprint and the safety of the battery system.

For the positive electrode, the project uses Prussian Blue analogues. These iron-based compounds are non-toxic, widely available and well suited for sodium-ion storage. First used as pigments centuries ago, they now play a role in next-generation energy storage materials.

Relevance for Designers and the Built Environment

Initial test results are encouraging. Prototype cells have completed more than 100 charge–discharge cycles without major performance loss. The project aims to reach at least 200 cycles in a 1-Ah full cell. While the technology is not intended for fast charging, it suits applications with moderate power demands.

For architects and landscape designers, lignin-based sodium-ion batteries could support future building-integrated energy storage systems or local renewable grids. Product and mobility designers may find opportunities in low-speed electric vehicles, warehouse logistics equipment or modular storage units. These applications benefit from safer chemistry, material transparency and reduced reliance on critical raw materials.

By transforming a forestry by-product into a functional energy material, the ThüNaBsE project shows how circular and biobased material strategies can extend beyond construction products. Energy storage, often overlooked in material discussions, becomes part of a more holistic and sustainable design approach.

Source & image: Fraunhofer Institute for Ceramic Technologies and Systems IKTS