Voltage Hysteresis of Silicon Nanoparticles: Chemo-Mechanical Particle-SEI Model

Abstract

Silicon is a promising anode material for next-generation lithium-ion batteries. However, the volume change and the voltage hysteresis during lithiation and delithiation are two substantial drawbacks to their lifetime and performance. We investigate the reason for the voltage hysteresis in amorphous silicon nanoparticles covered by a solid-electrolyte interphase (SEI). Concentration gradients inside the nanoscale silicon can not produce the massive stresses necessary to cause the reported voltage hysteresis. Our chemo-mechanical model shows that plastic deformation of the stiff, inorganic SEI during lithiation and delithiation reproduces the observed silicon open-circuit voltage hysteresis. Additionally, the viscous behavior of the SEI explains the difference between the voltage hysteresis observed at low currents and after relaxation. We conclude that the visco-elastoplastic behavior of the SEI is the origin of the voltage hysteresis in silicon nanoparticle anodes. Thus, consideration of the SEI mechanics is crucial for further improvements.

References in corpus (4)

• In Situ Measurements of Stress Evolution in Silicon Thin Films During Electrochemical Lithiation and Delithiation
• A Finite Strain Model of Stress, Diffusion, Plastic Flow and Electrochemical Reactions in a Lithium-ion Half-cell
• In Situ Measurements of Stress-Potential Coupling in Lithiated Silicon
• Growth of the Solid-Electrolyte Interphase: Electron Diffusion versus Solvent Diffusion

Cited by in corpus (2)

• Silicon Nanowires as Anodes for Lithium-Ion Batteries: Full Cell Modeling
• Inactive Overhang in Silicon Anodes