Effect of binder on electrochemical performance of Silicon/Graphene anodes for Lithium ion batteries

Abstract

The sun is not always shining, and the wind is not always blowing, hence energy storage becomes an essential part of human life. Among the energy storage technologies, batteries are touted to be the front runners, especially Lithium-ion batteries (LIBs) with their existing infrastructure offer solutions to the current barriers in this field. The era of battery powered vehicles has made the need for growth in LIB’s even more evident, as more and more vehicles are deployed every year. However, current LIB’s lie far behind gasoline powered vehicles owing to their low energy density. Range anxiety has been a major hindrance to the deployment of electric vehicles (EVs). To tackle this issue, researchers have transitioned from traditional graphite anode to different chemistries. Silicon anodes, owing to their extremely high theoretical capacity and its high abundance has gained a lot of attention. However, silicon expands nearly 3 times its original size leading to issues like pulverization and delamination that cause severe capacity decay. This has been a major impediment to the commercialization of Si anodes. In this work, various strategies have been discussed to overcome these issues. The significance of properties in binders, a polymeric material used to bind the electrode components, and maintain the electrode integrity has been discussed. Moreover, the effect of silicon (active material) particle size on the electrochemical performance has been investigated. The results demonstrate the significance of binder molecular weight, an important property that determines the coulombic efficiency and capacity retention. Further results show the importance of silicon size and the addition of electrode modifications that render a stable capacity over several cycles of deep discharge. The results show a successful demonstration of a scalable and economically feasible fabrication technique to mitigate volume expansion in silicon-based anodes.