Unraveling Lithium Storage and Defect-Modulated Transport in 2D Copper Boride: From First Principles to Machine-Learned Molecular Dynamics
Abstract
In this work, we combine first-principles calculations, ab initio molecular dynamics (AIMD), and machine-learning-interatomic-potential molecular dynamics (MLIP-MD) to investigate lithium storage and transport in two-dimensional Cu8B14, including an experimentally identified line-defect configuration. Pristine Cu8B14 remains metallic upon lithiation and exhibits favourable Li adsorption, a single-surface theoretical capacity of 427~mAh~g−1, and an average open-circuit voltage of approximately 0.53~V. The lowest Li migration barrier on the pristine surface is 0.32~eV. The line-defected structure retains a capacity of approximately 400~mAh~g−1 while reducing the local migration barrier to 0.21~eV. To access Li dynamics beyond the picosecond time scale of AIMD, a pretrained MACE-MP-0 model was fine-tuned against system-specific DFT energies and forces and employed in nanosecond-scale simulations from 400 to 600~K. Both pristine and line-defected lithiated monolayers remain structurally stable over this temperature range. At 400~K, the line-defected system exhibits a higher in-plane Li tracer diffusivity (3.97×10−5~cm2~s−1) than the pristine monolayer (2.50×10−5~cm2~s−1), whereas the pristine system becomes more diffusive at 500 and 600~K. Arrhenius analysis yields effective activation energies of 0.147 and 0.225~eV for the line-defected and pristine systems, respectively. These results show that the line defect modifies the Li-transport landscape and its temperature dependence rather than uniformly enhancing long-range diffusion, while preserving competitive Li-storage capacity and structural stability.
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BibTeX
@misc{sarkar2026unraveling,
title = {{Unraveling Lithium Storage and Defect-Modulated Transport in 2D Copper Boride: From First Principles to Machine-Learned Molecular Dynamics}},
author = {Subhasis Sarkar and Rajnendra Singh and Brahmananda Chakraborty and Sridhar Sahu},
howpublished = {arXiv},
year = {2026},
month = sep,
doi = {10.48550/arxiv.2608.12824},
eprint = {2608.12824},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2608.12824},
}
RIS
TY - UNPB
TI - Unraveling Lithium Storage and Defect-Modulated Transport in 2D Copper Boride: From First Principles to Machine-Learned Molecular Dynamics
AU - Subhasis Sarkar
AU - Rajnendra Singh
AU - Brahmananda Chakraborty
AU - Sridhar Sahu
PY - 2026
DA - 2026/09/25
PB - arXiv
DO - 10.48550/arxiv.2608.12824
UR - https://arxiv.org/abs/2608.12824
AB - In this work, we combine first-principles calculations, ab initio molecular dynamics (AIMD), and machine-learning-interatomic-potential molecular dynamics (MLIP-MD) to investigate lithium storage and transport in two-dimensional Cu_8B_14, including an experimentally identified line-defect configuration. Pristine Cu_8B_14 remains metallic upon lithiation and exhibits favourable Li adsorption, a single-surface theoretical capacity of 427~mAh~g^−1, and an average open-circuit voltage of approximately 0.53~V. The lowest Li migration barrier on the pristine surface is 0.32~eV. The line-defected structure retains a capacity of approximately 400~mAh~g^−1 while reducing the local migration barrier to 0.21~eV. To access Li dynamics beyond the picosecond time scale of AIMD, a pretrained MACE-MP-0 model was fine-tuned against system-specific DFT energies and forces and employed in nanosecond-scale simulations from 400 to 600~K. Both pristine and line-defected lithiated monolayers remain structurally stable over this temperature range. At 400~K, the line-defected system exhibits a higher in-plane Li tracer diffusivity (3.97×10^−5~cm^2~s^−1) than the pristine monolayer (2.50×10^−5~cm^2~s^−1), whereas the pristine system becomes more diffusive at 500 and 600~K. Arrhenius analysis yields effective activation energies of 0.147 and 0.225~eV for the line-defected and pristine systems, respectively. These results show that the line defect modifies the Li-transport landscape and its temperature dependence rather than uniformly enhancing long-range diffusion, while preserving competitive Li-storage capacity and structural stability.
ER -