Investigation of Spray Conditions and Performances of Cold-sprayed Pure Silicon Anodes for Lithium Secondary Batteries

Abstract

Abstract Currently, graphite is used for anodes of the lithium ion battery. The higher capacity of a battery with the lithium alloy anode requires the development of a larger theoretical electrochemical capacity than graphite. Silicon is a promising anode material, having a theoretical capacity more than 10 times that of the graphite used in these lithium alloy batteries. There are two common methods of fabricating silicon anodes: direct deposition techniques such as electron beam deposition and sputtering; and slurry coating of silicon particles with a binder. Alternative methods are being investigated. One of such methods is cold spray. In this study, numerical simulation of, and experiments investigating, cold spray conditions and the performances of cold-sprayed silicon anodes are presented. Silicon was cold-sprayed on copper foil substrates using three different starting materials (with particle sizes of 4.65 µm, 6.74 µm and 9.63 µm). First cycle efficiency was about 90%. Charge capacity initially improves with cycling (up to the 10th cycle). This is probably due to better electrolyte soaking during the first several cycles. A decrease in charge capacity is observed upon further cycling.