Stabilisation of Metal Anodes for Long-life Lithium-Sulfur Batteries (SiMBa)

In order to meet the UK's net-zero goals, new energy storage technologies that can store enough energy for large transport applications on land, air and sea will be required. The lithium-ion batteries that have revolutionised the EV market lack the gravimetric energy density needed for such high-energy applications. Lithium-sulfur batteries exploit redox reactions on sulfur-based positive electrodes, rather than the metal oxide found in lithium-ion batteries, offering drastic enhancements in energy density and potentially game-changing progress in electrified transportation. The most pressing challenge is to extend the cycle life to the thousands of cycles needed in transport applications. In current systems the lithium metal electrode reacts with dissolved sulfur species found in the liquid electrolyte resulting in degradation and hindering long-term cycling of the battery. Gelion has pioneered the quasi-solid-state lithium-sulfur battery, which contains a high concentration electrolyte that forces the sulfur and its intermediates into the solid-state, significantly improving the battery performance by preventing sulfur loss from the electrode. However, the reaction between the lithium metal and the cell components remains problematic for long term use and cycle life does not meet requirements for large transportation applications. The University of Nottingham and Gelion have co-developed this proposal to tackle this problem by developing hybrid electrolyte cells. This ambitious target can only be met through the synergistic collaboration of our teams. In the hybrid electrolyte cell, lithium metal is protected from reacting with the cell components by coating it with a solid electrolyte, which is in turn separated from the positive electrode by the high concentration electrolytes used in the quasi-solid-state lithium-sulfur battery. Degradation reactions between the solid and liquid electrolytes are expected, and these will be studied using fundamental chemical and electrochemical methods to understand the mechanism of these unknown reactions and determine how they impact the electrochemical properties of the cell. The impact of these degradation processes on cell performance will be determined and mitigation strategies will be employed, such as the addition of protective coatings onto the surface of the solid electrolytes to stabilize the solid-liquid interface. We aim to build a lab-scale prototype cell that can achieve hundreds of cycles with high capacity retention. The programme will yield significant new intellectual property which will be captured through close collaboration between the academic and industrial partners for exploitation and commercialization of the quasi-solid-state lithium-sulfur battery within the UK.