Studies of Lithium Diffusivity of Silicon-Based Film Electrodes for Rechargeable Lithium Batteries

Abstract

Lithium diffusivity of the silicon (Si)-based materials of Si-Cu and SiO x (x = 0.4, 0.85) with improved interfacial stability to electrolyte have been determined, using variable rate cyclic voltammetry with film model electrodes. Lithium diffusivity is found to depend on the intrinsic properties of anode material and electrolyte; the fraction of oxygen for SiO x (x = 0.4, 0.85), which is directly related to electrical conductivity, and the electrolyte type with different ionic conductivity and viscosity, carbonate-based liquid electrolyte or ionic liquid-based electrolyte, affect the lithium diffusivity.

Mitigating Metal-dissolution in a High-voltage 15 wt% Si-Graphite‖Li-rich Layered Oxide Full-Cell Utilizing Fluorinated Dual-Additives

“…Silicon (Si)-graphite anode active material has been studied and developed for decades for its potential applicability to high-energy density Li-ion battery. The Si represents a high-capacity anode material due to the high theoretical specific capacity of Si (3579 mAhg −1 , when charged to Li 15 Si 4 ), which is more than 9-fold of the capacity of graphite (372 mAhg −1 ) [5][6][7][8][9][10][11][12][13]. As increasing the fraction of Si in the Si-graphite composite, capacity is expected to increase.…”

“…Commercial LIBs therefore employs the Si content lower than 5 wt%. In addition, the SEI formation and stabilization technology is extremely important in achieving a good performance of Si-graphite anode [8][9][10]. Fluoroethylene carbonate (FEC) is a well-known SEI-forming agent on both Si and graphite, which has a lower the lowest unoccupied molecular orbital (LUMO) energy level than that of EC of conventional electrolyte.…”

Experimental visualization of reversible magnesium storage and surface chemistry of magnesium silicide anode

“…Film model electrode deposited on electronically conductive substrate comprises no complications from carbon and polymeric binder additives that are necessary in bulk porous electrodes, and can provide high-quality spectroscopic signals and a precise characterization of the surface composition, which gives a clear insight into electrode-electrolyte interfacial processes and reaction mechanisms. 15,29,30,[32][33][34][35][36] Herein, for the first time, we demonstrate the experimental visualization of a reversible Mg storage ability of Mg 2 Si film model electrode in the Mg||Mg 2 Si half-cell with the electrolyte of 0.5 M phenyl magnesium chloride (PhMgCl) in tetrahydrofuran (THF) at room temperature for Mg-ion battery. The Mg 2+ -diffusivity of Mg 2 Si, determined utilizing variable rate cyclic voltammetry, reveals very sluggish diffusion kinetics that is four orders of magnitude lower than that of Li + -diffusivity of Mg 2 Si.…”