Stress effects on the initial lithiation of crystalline silicon nanowires: reactive molecular dynamics simulations using ReaxFF (reduced PDF duplicate)

PDF variant

Reduced PDF duplicate. Full figures and pagination: 2015ostadhossein-physical-che-stress-effects (papers/Ostadhossein_PCCP_LiSi_2014.pdf). See also NON_PRIMARY list: proof sibling 2014ostadhossein-venue-rsc-cp.

Summary¶

This slug registers a reduced-page PDF copy papers/Ostadhossein_PCCP_LiSi_2014_reduced.pdf of the PCCP article DOI 10.1039/C4CP05198J, “Stress effects on the initial lithiation of crystalline silicon nanowires: reactive molecular dynamics simulations using ReaxFF.” The extract (normalized/extracts/2015ostadhossein-physical-che-stress-effects-2_p1-2.txt) reproduces the abstract and opening Introduction: silicon anodes promise high capacity; in situ TEM shows lithiation of crystalline Si nanowires proceeds via migration of the interface between lithiated shell and pristine core with solid-state amorphization; and the paper uses ReaxFF MD to characterize mechanisms. The abstract states ReaxFF reproduces Li migration barriers from DFT in both crystalline and amorphous Si; that Li insertion between adjacent {111} planes leads to peeling-off of {111} facets and amorphization consistent with experiment; that breaking Si–Si bonds between {111} bilayers requires high local Li concentration, explaining a sharp ACI; that stress analysis shows compressive stress at the ACI layer retarding the front, matching TEM; and that high-temperature lithiation (example 1200 K) can produce an amorphous-to-crystalline transformation near Li:Si ≈ 4.2:1. Full figures and any SI pages may be absent compared with 2015ostadhossein-physical-che-stress-effects.

Methods¶

This slug registers only a reduced-page PDF duplicate of DOI 10.1039/C4CP05198J; the simulation protocol is identical to 2015ostadhossein-physical-che-stress-effects (same PCCP article). Reactive MD uses LAMMPS with ReaxFF (Fan Si–Li parameters) on an h112 crystalline Si nanowire of ~5976 Si atoms in a ~8.43×9.22 nm² cross-section with periodic boundary conditions (PBC) in-plane, a Li reservoir, a reflective top boundary, and a fixed bottom layer. Timestep: 0.25 fs (velocity Verlet). Thermostat: Nosé–Hoover NVT during thermalization (~10 ps from ~1 K, ramp to 600 K at 0.048 K/fs, then hold ~2.2 ns in the equilibration segment described in the paper) with additional NVE segments where the article reports virial stress at the amorphous–crystalline interface. Production lithiation uses the NVE/NVT staging described on 2015ostadhossein-physical-che-stress-effects (full segment lengths, stress panels, and any SI pages live on the canonical PCCP PDF, not necessarily in this reduced export). Temperature (K): protocols span cryogenic initialization (~1 K), a ramp toward 600 K during thermalization, ~300 K lithiation–stress analyses at the reaction front, and ~1200 K high-temperature Li–Si examples in the abstract. Barostat / hydrostatic pressure: N/A — constant-volume nanowire workflow. Electric field / metadynamics: N/A.

Findings¶

Mechanisms / outcomes: the abstract on the reduced PDF matches the canonical article: ReaxFF reproduces DFT Li migration barriers in c-Si and a-Si; {111}-channel Li insertion drives peeling, amorphization, and a sharp amorphous–crystalline interface; compressive stress at that interface can retard the reaction kinetics of the lithiation front.

Comparisons: trends are discussed relative to in situ TEM observations of Si nanowire lithiation and relative to DFT barrier benchmarks in the PCCP article.

Sensitivity: behavior depends strongly on temperature (room-temperature stress-limited fronts versus ~1200 K pathways) and on Li:Si loading (example amorphous→crystalline Li–Si transition near Li:Si ≈ 4.2:1 at high temperature in the abstract).

Limitations / outlook: this slug’s duplicate PDF may omit figures or SI pages; quantitative stress fields and barrier tables should be read from the version-of-record file on 2015ostadhossein-physical-che-stress-effects, not from cropped proof/reduced exports.

Limitations¶

Reduced PDFs may omit pages present in the primary file; always prefer papers/Ostadhossein_PCCP_LiSi_2014.pdf for complete content.

Relevance to group¶

Duplicate PDF registration for the same PCCP article; use 2015ostadhossein-physical-che-stress-effects for figures, SI, and pagination when citing quantitative stress or ACI data.

Citations and evidence anchors¶

DOI: 10.1039/C4CP05198J