Crack propagation mechanisms in amorphous LiSi alloys: Insights from molecular dynamics

Abstract eng:
g Despite apparent promise of silicon as anode material for lithium-ion batteries, the fiacture characteristics of lithiated Si are largely unknown. Here, we report an atomistic study of the fiacture toughness of lithiated Si for LixS i compositions of x = 0.5, 1.0, 1.5. We measure similar near-steady-state fracture toughness for all compositions, with void nucleation and coalescence observed to be the main mechanism of crack growth. With increasing Li content, the plastic flow stress decreases but the material becomes more susceptible to void nucleation and growth. To gain more insight, simulations of plane-strain expansion of uncracked samples provide complementary information on the void nucleation and growth, consistent with the fracture simulations. We also investigate the effect of discharging and show that the increased structural disorder generated by discharging decreases the flow stresses but expedites void nucleation and growth, indicating that the flow and fracture of lithiated silicon depends on the history of charging/discharging.

• Export as: BibTeX | MARC | MARCXML | DC | EndNote | NLM | RefWorks
• Add to your basket