(Digital Presentation) Approaches of Pre-Lithiation on Si Anode for Lithium-Ion Batteries

Abstract

Silicon is one of the most attractive anode materials for next generation high-capacity lithium-ion batteries (LIBs) due to its high specific capacity. However, the large volume change (up to 300%) of silicon during lithiation/delithiation process leads to coupled mechanical and chemical degradation, such as pulverization of silicon particles, formation of unstable solid-electrolyte interphase (SEI), and loss of electrical connectivity, resulting in high irreversible capacity loss and rapid capacity fading. Pre-lithiation is one of the effective approaches to compensate for the loss of active lithium and extend battery cycle life. In this work, various approaches of pre-lithiation for Si electrodes are systematically studied and compared. Different levels of pre-lithiation dosage are applied to the Si electrodes and the pre-lithiated Si electrodes are evaluated in NMC622/Si full cell configuration. After pre-lithiation, the cell capacity and cycling stability are significantly improved. The impacts of operating voltage window, and N/P ratio on electrochemical performance are also investigated. The morphology of pre-lithiated Si electrodes before and after cycling are also compared via cross section scanning electron microscopy (SEM) to understand the electrode expansion and SEI formation/growth during cycling.