Batteries can store electric charges through electrochemical transformations within the electrodes. Consequently, the electrode materials define the performance of the battery. We are looking at different charge-storing materials for Li-ion and Na-ion batteries to improve capacity, life-time and safety. Moreover, we are also investigating new formulations to bind and connect the charge storing materials within the electrode. By using electronically conductive binders, based on conjugated polymers, electrodes work more efficiently and over a larger number of cycles.
As battery electrodes store and release charge, materials are expanding and contracting. This leads to cracking and disconnection of materials from their matrix, which ultimately causes capacity decay. We are interested in imaging electrodes by X-ray tomography and microscopy in order to investigate disconnection mechanisms and follow strategies to accommodate large volume changes without material disconnection.
Li-ion batteries suffer from a bad safety reputation. Clearly, the larger batteries get (think electric car, truck, grid storage), the more energy they store in a small place, the larger the potential catastrophe. For this reason, we are investigating a much safer alternative to current Li-ion technology, in which the flammable and reactive liquid electrolyte is replaced by a solid electrolyte. We are testing new methods to produce thick all-solid-state composite electrodes, that contain only charge-storing material, solid electrolyte material and binder.