Sustainability From Cradle To Grave: Halide Based Electrolytes For All-Solid-State Batteries

The development of all-solid-state-batteries and beyond Li-ion battery technology is crucial to increase the safety and lower the cost of rechargeable batteries for electric transport and grid storage applications. All-solid-state batteries can improve battery capacity and sustainability through the use of cobalt-free, high-voltage, manganese-rich (Mn-rich) cathode materials. These cathodes cannot be used in conventional batteries due to dissolution of manganese into the liquid electrolyte.

Lithium (Li) halide materials, such as Li3YCl6 are a new class of solid-state electrolytes that will be key for enabling Mn-rich all-solid-state batteries to be commercialised. However, the interfacial transport at Mn-rich cathode/halide solid-state electrolyte interfaces is poorly understood. Current halide solid-state electrolytes are also universally unstable against alkali metal anodes, such as lithium (Li) metal, which limits their practical use.

In this Fellowship, Dr Seymour's team will develop novel Li and beyond-Li halide materials for all-solid-state batteries with high sustainability from materials synthesis to recycling of battery components. Three key research questions will be addressed: (1) How can halide SSEs be used to facilitate sustainable Mn-rich cathode technologies?

(2) Can halide SSEs be used in beyond-Li all-solid-state batteries? (3) Can halide SSEs facilitate sustainable recycling of all-solid-state batteries?

A novel computational and experimental platform will be developed to study the atomistic processes occurring at the interfaces between Li halide solid-state electrolytes and sustainable Mn-rich cathodes. The transport of atoms at the Mn-rich cathode/halide solid-state electrolyte interface will be captured for the first time on experimental timescales (microseconds to seconds) using state-of-the-art adaptive kinetic Monte Carlo (aKMC) simulations.

The insights gained will be crucial for the development of high performance, patentable all-solid-state battery technology. Guided by the models developed in research question (1), novel beyond-Li SSE materials will be designed. To date, there have only been a tiny number of studies on 'beyond Li' chemistries for sodium (Na), potassium (K), magnesium (Mg) and calcium (Ca) all-solid-state batteries. There is therefore a vast phase space of Na, K, Mg and Ca halide conductors to be discovered.

Efficient recycling and recovery of battery components is essential for rechargeable batteries to be a truly sustainable technology but is an extremely underdeveloped research area. A sustainable closed-loop recycling protocol will be developed in which the unique chemistry of halide solid-state electrolytes is exploited to minimise waste from all stages of the battery's lifecycle, from materials synthesis to end of life.

The final goal of this work is to develop sustainable Mn-rich, all-solid-state batteries that will be scaled up for commercial applications with academic and industrial partners. The transformative research platform developed in this Fellowship will be widely transferable to other sustainable energy materials applications and has the potential to make Dr Seymour's team, and the UK, a leader in the development of green all-solid-state battery technology.