Sehee Lee

Abstract:

The demand for the full implementation of lithium-ion batteries (LIBs) in powering applications such as electric vehicles has promoted vast research towards new materials with higher capacities and longer lifetimes. Commercialized graphite anodes stand far from achieving this goal due to their capped specific capacity of 372 mAh g-1. The search for new anode materials capable of reversibly retaining large amounts of lithium is a necessity in creating advanced LIBs. One such material is silicon (Si), which is naturally abundant and able to form LixSi compounds, where x can reach a value of 3.75 at room temperature corresponding to a specific capacity of 3579 mAh g-1. However, the alloying of lithium into Si leads to an increase in its specific volume of about 300%, creating a number of challenges that have retracted the implementation of Si as a LIB anode material. The stress induced by large volume changes of the Si anodes causes material degradation and major problems for electrochemical performance. In addition to the material degradation, the inherent volume change of Si also induces composite electrode thickness expansion and external cell deformation. From a practical point of view, cell deformation is as important as electrochemical performance and it is the critical factor limiting the commercialization of Si-based anode materials. In this work, we present the manufacturing of a scalable and low-cost material that attains a lowest electrode deformation ever reported.