Researchers Develop Sustainable Sodium-Ion Batteries from Lignin

Innovative researchers in Germany are advancing the development of sustainable sodium-ion batteries using lignin, a by-product of the wood and pulp industry. This initiative, part of the ThüNaBsE (Thuringia Sodium-Ion Battery for Scalable Energy Storage) project, aims to create cost-effective and environmentally friendly energy storage solutions. The project is spearheaded by the Fraunhofer Institute for Ceramic Technologies and Systems IKTS in collaboration with the Friedrich-Schiller-University Jena and the Center for Energy and Environmental Chemistry Jena (CEEC).

The demand for efficient energy storage systems is escalating due to the global transition towards renewable energy. Traditional lithium-ion batteries often rely on critical raw materials that are not only costly but also pose environmental concerns. In contrast, sodium-ion batteries, particularly those based on lignin, offer a promising alternative. Lignin, a biopolymer that provides structural stability to wood, is typically incinerated for energy recovery. However, researchers are now repurposing it for battery production.

The ThüNaBsE project focuses on transforming lignin into high-performance electrodes while simultaneously mitigating the reliance on rare metals like lithium, cobalt, and nickel. Lukas Medenbach, a research scientist at Fraunhofer IKTS, emphasizes the project’s goal of minimizing fluorine content in the battery components. He notes the importance of processing high-quality lignin into effective negative electrodes for sodium-ion batteries.

The lignin used in the project is sourced from Mercer Rosenthal GmbH. Under controlled conditions, it undergoes thermal conversion into carbon, which is then processed into electrodes. Collaborating scientists at the University, led by Prof. Martin Oschatz, utilize thermal methods to produce what is termed “hard carbon.” This material is well-suited for reversible sodium ion storage, boasting advantages such as high electrochemical performance and cost-effectiveness when derived from sustainable resources.

Building and Testing Battery Prototypes

The project is currently in the prototype phase, with small demonstrator cells being constructed and assessed at the Fraunhofer IKTS battery test center in Arnstadt, as well as at facilities in Hermsdorf and Jena. The research team is employing realistic simulations alongside laboratory experiments to evaluate performance. Early results indicate promising durability; after 100 charging and discharging cycles, the lab cell exhibits no significant degradation. The objective is to achieve a total of 200 cycles for the 1-Ah full cell by the project’s conclusion.

Once fully developed, these lignin-based sodium-ion batteries are expected to find applications in both stationary and mobile storage systems. They could be particularly well-suited for microcars, which have a speed limit of 45 km/h, and for logistics vehicles such as forklifts, where rapid charging is less critical.

The initiative not only aims to advance battery technology but also to foster the next generation of researchers. Several young scientists pursuing doctoral degrees in energy and battery research are actively involved in the ThüNaBsE project, contributing to a collaborative learning environment.

Looking ahead, the project partners plan to scale the technology further and explore higher levels of technological maturity by forming a larger consortium. This effort could significantly influence the future of energy storage solutions, supporting the transition to more sustainable and safer battery technologies.