(Battery Division Postdoctoral Associate Research Award Address Sponsored by MTI Corporation and the Jiang Family Foundation) Li Plating During Fast Charge: Detection and Prevention

Abstract

Enabling fast charge of lithium-ion batteries is an essential step towards the wider adoption of electric vehicles. A key challenge is that high charging currents can promote several aging mechanisms, including lithium plating on the graphite anode. There is research suggesting that the deposition of metallic lithium favors further Li plating in a self-reinforcing loop, which can eventually lead to sudden cell failure.[1] Hence, detecting Li deposition during the early stages and developing electrochemical cycling protocols that avoid plating conditions are crucial to enabling fast-charge.In this talk we will discuss two approaches to investigate Li deposition. The first one is through detection. Our group has demonstrated that plated Li can intensify the Raman signal of its surrounding SEI, which then serves as an indirect marker for the presence of Li nuclei.[2] The sensitivity of this technique enables the study of where Li will tend to plate, and how this deposition evolves spatially over the course of many cycles. The second approach is through the use of a reference electrode, which can be used to estimate electrode potentials during fast charging.[3] This capability supports the development of fast-charging protocols that optimize time utilization while steering the cells away from Li plating conditions. Examples of such cycling protocols will be discussed during the presentation.