Paper byproduct lignin’s potential for capacitors, sodium-ion batteries

An interdisciplinary research team from the Center for Energy and Environmental Chemistry (CEEC Jena) is looking to upgrade lignin from a timber industry waste product to a recyclable material, which could be used in place of critical metals as electrode material in energy storage capacitors and sodium-ion batteries.

As part of the project dubbed “LignUp”, the researchers will investigate whether lignin can be used as a starting material for such functional materials that make energy storage systems more environmentally friendly. The project will receive almost EUR 5 million (USD 5,399,325.00) in funding from the Carl Zeiss Foundation over the next six years.

While batteries usually still contain critical metals such as lithium, cobalt or manganese, Martin Oschatz, professor of Chemistry of Materials for Energy Applications (CEEC) at University of Jena, and his team will look for new lignin-based battery materials that no longer require these metals.

Lignin can also be used to synthesize new types of filter materials that can selectively separate metals from aqueous solutions. This would allow critical metals to be recovered in sustainable battery recycling processes or extracted in a greener way in water-based ore processing. This will form the second pillar of the project.

“Attempts are already being made to separate interesting metals from seawater or special mining waters using membranes or adsorption materials. In the future, water-based recycling processes for metals will follow – for example from battery recycling. We therefore want to build up a material library and develop synthesis routes that can be used to customize new functional materials from lignin components that are better suited to the extraction of metals from water,” said Oschatz.

As well as its potential to help make the energy storage industry more environmentally friendly, the research provides a possible novel use for lignin – currently a byproduct of the paper industry.

Lignin’s main purpose is to keep wood in trees stable. It is not needed for processing wood into paper. According to Oschatz, “the pulp industry accumulates around 50 million tons of lignin worldwide every year. The majority of this is simply incinerated.”

Lignin is too valuable to be discarded, Oschatz believes. “Like cellulose and other biopolymers, it consists of hydrocarbon building blocks that can be utilized much more effectively in chemistry,” he says.

The LignUp project marks the start of a new focus on bioeconomy and energy storage materials at CEEC Jena, said Michael Stelter. The environmental chemist co-leads the project alongside Oschatz.

“For the first time, we are linking industrial bioeconomy with energy technology in a cross-industry way. Due to its versatile chemical structure, lignin is a very suitable starting material.” Steltner added that lignin’s abundance means it is a reliable domestic raw material and is therefore suited for large-scale industrial utilization.

The University of Jena group is not the only team exploring the potential of lignin for the battery industry. In June, ESS News reported that Swedish battery company Altris partnered with Stora Enso to develop hard carbon anode for its sodium-ion batteries based on lignin.