Structured electrodes for improved energy storage

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The development of Li ion batteries (LiBs) has progressed through the evolution of improved electrochemically active electrode materials and has provided steady improvements in performance. Every LiB battery comprises two electrodes (anode and cathode), each made up of three materials: the electrochemically active material, a binder (typically a polymer) and an electrical conductivity enhancer (typically carbon black). The relative fractions of these three materials, blended together with a fugitive liquid into a slurry, plus the final electrode porosity that allows the liquid electrolyte to flood into the electrode, are optimized based on exhaustive electrochemical testing. Commercial tools are available to help guide this optimisation but are useful only for the most conventional types of electrode. As new manufacturing approaches that allow for more controlled arrangements of the materials to form "structured electrodes" are invented and the resulting devices show better performance, there arises an exciting opportunity to identify, from the uncountable number of possible 2D and 3D spatial arrangements of the electrode materials, those which offer significant improvements in device performance in particular applications. However, to achieve this optimisation through current empirical approaches is impossibly slow and expensive.This proposal will develop a suite of modelling tools bridging micro to macro lengths-scales to guide the optimization of the spatial distribution of electrode structure to advance the performance, lifetime and introduction of next generation energy storage devices. This design optimization is especially critical where LiB and other systems are pushed to their limits e.g. high power (rapid charge/discharge) applications for EVs, or where ion mobility is otherwise restricted, such as inherently safe but low ionic mobility solid-state batteries. Insights generated will include the optimal spatial arrangements (in three dimensions) of porosity, particle size, binder, porosity for different materials, device formats and applications, how they could be manufactured, and how their properties vary with time in operation. The novelty of our methodology is: (1) a new approach to describe the dynamics of ion movement in energy storage electrodes efficiently that allows the models to be used in optimisation even when significantly more degrees of freedom are available, and (2) the use of a new manufacturing capability for large scale structured electrodes for model validation. By linking models, design optimisation, manufacture and performance measurements the programme will deliver material-independent and generic tools for optimisation of any Li ion, Na ion, supercapacitor or other electrode-based device, within the context of strong industrial guidance and engagement.