Speaker: Professor Patrick Grant FREng, Department of Materials, Oxford University, UK.
Since the invention of the Li ion battery more than 30 years ago, there have been steady improvements in performance such as energy and power density. However the most dramatic change has been the reduction in cost per unit energy stored due to manufacturing innovations, which have reduced costs by more than an order of magnitude. While costs continue to reduce, albeit more slowly, battery performance is beginning to stagnate. However, this plateau of performance is disappointingly well-below the intrinsic energy storage performance of the active cathode and anode materials that comprise the Li ion battery. The root of the performance plateau is the ubiquitous method of creating the electrodes, which although highly productive, constrains the range structures and performance that can be achieved. This talk explores novel ways of producing electrodes used in Li ion and Na ion that have structures that allow the intrinsic energy storage capabilities of materials to be realised more fully. For example, we have developed manufacturing techniques that provide extra control on how a polymeric binder distributes during the drying of a slurry cast Li ion battery electrode, how to eliminate organic solvents used in electrode processing, and how to mix optimally different active materials in a single electrode. By improving microstructural control, battery performance is enhanced, and the design space for battery electrode architectures and performance is widened. Because design options are increased, trial and error electrode optimisation by experiment typical of the battery industry becomes impossible. Therefore, the use of modelling and simulation becomes essential, both to understand the electrochemical behaviour of our smart hetero-electrodes and to guide the microstructural design of electrodes for a particular balance of desired properties.