Passive Components in Next Generation Li-Ion Batteries

Most of the research in development of next generation and high-performance Li-ion batteries has focused on active materials (either in the cathode or anode side). This might sound obvious as active materials are the main component responsible for storing charge in batteries, and therefore, any improvement in them, will directly impact the overall performance of the battery. However, when looking at the cell level, passive components such as current collectors, conductive additives, binders, and separators constitute around 20 wt.% of each battery cell. These so-called passive components while do not directly contribute to the charge storage, their ratio, composition, and structure has a profound effect on the overall performance of the active material and therefore the battery cell. This is mainly due to their importance in charge transport inside the electrode, processing of electrodes, and also cycle life the battery cells. Despite this, they usually receive less attention in development of high power and energy density batteries. If these components are engineered properly or substitute with alternative new materials, potentially, one can improve the performance (energy and power metrics) of a Li-ion battery cell by up to 20%; a number that industry still strives to achieve through modification of active materials which usually is a more complex issue with slower development timeframes. In this talk, we take a closer look at the role of passive components in Li-ion batteries and discuss the possibilities that novel nanomaterials can offer as next generation passive components, both from the standpoint of improvements in metrics of battery cells as well as electrode processing and manufacturing in Li-ion batteries. We will also discuss the cost and safety advantages these materials can offer when used as passive components of the cells and present results and give examples that demonstrate how nanomaterials can in fact act as semi-passive components where they can substitute multiple conventionally used passive components and serve multiple purposes even if directly do not contribute to charge storage. Taking such an approach in development of battery electrodes/cells can potentially pave the way for development of batteries with higher power and energy densities using the current commercially available active materials, and further enable the use of high-capacity materials that degrade quickly and therefore, cannot be used in commercial cells using current technologies.