Challenge

The performance of electric cars and everyday electrical devices is limited by battery technology. This project sought to address the problems associated with the use of graphite in battery anode production in lithium ion batteries. Graphite creates limits on charge capacity.

Silicon is a potential alternative to graphite and is known to increase the charge capacity but poses issues with the amount of expansion and contraction it undergoes during the charge/discharge cycle.

Incorporating silicon in the anode has significant potential to improve charge capacity by as much as ten times, but this material has its own limitations. Silicon anodes expand and contract by as much as 320% during the charge/discharge cycle with a devastating drop in capacity.

This collaboration aimed to address this silicon issue by using a novel nanostructuring strategy and tailored polymer binders to mitigate this volume change. An earlier project had demonstrated that sodium alginate inhibits this behaviour in silicon, extending LIB lifetimes to hundreds of cycles while increasing capacity by between four and ten times compared to graphite. This project would explore key areas for optimisation identified in the earlier project.

Solution

IBioIC awarded Marine Biopolymers Ltd and Professor Duncan Gregory of the University of Glasgow just under £100k Innovation Funding to support this project.

There were two main threads to the project – alginate tailoring and optimisation (upstream) and anode cell production (downstream). Various alginates were assessed and one, SV alginate, was identified for half and full cell prototyping. Although other alginates had limited success, the process gave valuable insight into how to tailor alginates further for anode binder use.

Significant improvements were made in the processing and assembly of the cells, resulting in consistent reproducibility and maximisation of the product.

Duncan Gregory’s team incorporated sodium alginates into silicon anodes and tested charge capacity and cycling. The project revealed multiple areas where optimisation was required which was a result of the partners being able to work side by side in both facilities. This highly collaborative approach meant there was a lot of cross training and upskilling from both sides.

Many of the issues encountered are not cited in literature suggesting that the multi-disciplinary nature and knowledge exchange has led to true improvement and innovation in the field.

Outcome

This project successfully produced a cost competitive and high performing MBL alginate for prototyping and end user evaluation in LIBs.  

This project has progressed the production of SV alginate anodes from proof of concept to late TRL 4. The cost viability of alginates as anode binder materials has been determined and a defined process from seaweed preparation through to cell production, that yields a vastly improved product to market state of the art, has been confirmed.

MBL are now hoping to be able to take a commercial solution to market within the next three to five years. 

Given that ~6% of global CO2 emissions result from passenger transport, disruptive LIBs would deliver transformative advances in charging capacity, recharge times and longevity without compromising safety, consequently supporting increased EV uptake and a clean energy transition.