New bio-gel electrolytes for Zn-lignin batteries

We propose a Zinc-Lignin battery as a new, low-cost energy storage solution using two of the most affordable electroactive materials: zinc and the biopolymer lignin, which makes up 30% of plants. To optimize its performance, we need to design an electrolyte that prevents dendritic growth, reduces hydrogen evolution, promotes zinc ion conductivity, and is compatible with lignin.

Aqueous Zn-ion batteries with aqueous electrolytes are promising due to their safety, low cost (36 SEK/kg), environmental friendliness, and high zinc abundance. The zinc anode offers a high theoretical capacity of 820 mAh/g, resulting in a low-cost capacity of 0.04 SEK/Ah. For the cathode, lignin, an abundant and inexpensive biopolymer (1-4 SEK/kg), is being considered. Combined with a conductor, lignin can form nanocomposites with a capacity of 80 mAh/g, making it a cost-effective battery material (0.01-0.04 SEK/Ah). Both materials are non-toxic, recyclable, and ideal for large-scale, stationary batteries with a cell voltage of 1.2V.

However, Zn-ion batteries face challenges like zinc dendrite formation, hydrogen gas evolution, and byproduct accumulation, limiting their commercial feasibility. While various strategies have been proposed to mitigate these issues, hydrogel electrolytes have recently emerged as a potential solution to improve stability.
The aim of this project is to design low-cost Zinc-Lignin battery cells, focusing on the electrolyte. We propose using bio-gels, such as agarose, to develop Zn-ion aqueous gel electrolytes that prevent dendrite growth, promote Zn-ion transport, and limit hydrogen evolution. The project goals include: (i) Developing high-performance Zn-ion aqueous gel electrolytes. (ii) Characterizing ionic transport and electrochemical stability in "water-in-polymer salt" electrolytes. (iii) Integrating lignin electrodes from Ligna Energy AB with the new electrolyte to create safe, scalable, cost-effective Zinc-Lignin batteries.

Involved in the project

Reverant Crispin, Ziyauddin Khan, Peter Ringstad, Leandro R. Franco, Anna Martinelli, Moyses Araujo 

Partners

Linköping University, Ligna Energy, Chalmers, Karlstad University

Funders

Ligna Energy, Linköping University, Swedish Energy Agency, Chalmers, Karlstad University