Abstract
Stabilizing the solid electrolyte interphase (SEI) remains a key challenge for silicon-based lithium-ion battery anodes. Alloying silicon with secondary elements like boron has emerged as a promising strategy to improve the cycle life of silicon anodes, yet the underlying mechanism remains unclear. To address this knowledge gap, how boron concentration influences battery performance is systematically investigated. These results show a near-monotonic increase in cycle lifetime with higher boron content, with boron-rich electrodes significantly outperforming pure silicon. Additionally, silicon-boron alloy anodes exhibit nearly three times longer calendar life than pure silicon. Through detailed mechanistic analysis, alternative contributing factors are systematically ruled out, and it is proposed that improved passivation arises from a strong permanent dipole at the nanoparticle surface. This dipole, formed by undercoordinated and highly Lewis acidic boron, creates a static, ion-dense layer that stabilizes the electrochemical interface, reducing parasitic electrolyte decomposition and enhancing long-term stability. These findings suggest that, within the SEI framework, the electric double layer is an important consideration in surface passivation. This insight provides an underexplored parameter space for optimizing silicon anodes in next-generation lithium-ion batteries.
| Original language | English |
|---|---|
| Article number | 2501074 |
| Journal | Advanced Energy Materials |
| Volume | 15 |
| Issue number | 32 |
| DOIs | |
| State | Published - Aug 26 2025 |
Funding
This work was supported by the funding provided by the U.S. Department of Energy's Vehicle Technologies Office (VTO) under the Silicon Consortium Project directed by Brian Cunningham and managed by Anthony Burrell. This work was authored in part by the National Renewable Energy Laboratory (NREL), operated by Alliance for Sustainable Energy, LLC, for the U.S. Department of Energy (DOE) under Contract No. DE-AC36-08GO28308. Project conception, carbon nanostructure synthesis, electrode fabrication, electrochemical, and SSRM characterization were conducted at NREL. ORNL is managed by UT-Battelle LLC for DOE under Contract DE-AC05-00OR22725. The NMC811 electrodes used in this manuscript were supplied by Argonne's Cell Analysis, Modeling, and Prototyping (CAMP) Facility, which is fully supported by the DOE VTO. The TEM work was carried out by using microscopes that are funded in part by a grant from the Washington State Department of Commerce's Clean Energy Fund. Part of the TEM work was carried out at the William R. Wiley Environmental Molecular Sciences Laboratory, a national scientific user facility sponsored by DOE, Office of Biological and Environmental Research and located at PNNL. PNNL is operated by Battelle for the DOE under Contract No. DE-AC05-76RL01830. The views expressed in the article do not necessarily represent the views of the DOE or the U.S. Government. The U.S. Government retains and the publisher, by accepting the article for publication, acknowledges that the U.S. Government retains a nonexclusive, paid-up, irrevocable, worldwide license to publish or reproduce the published form of this work, or allow others to do so, for U.S. Government purposes. This work was supported by the funding provided by the U.S. Department of Energy's Vehicle Technologies Office (VTO) under the Silicon Consortium Project directed by Brian Cunningham and managed by Anthony Burrell. This work was authored in part by the National Renewable Energy Laboratory (NREL), operated by Alliance for Sustainable Energy, LLC, for the U.S. Department of Energy (DOE) under Contract No. DE‐AC36‐08GO28308. Project conception, carbon nanostructure synthesis, electrode fabrication, electrochemical, and SSRM characterization were conducted at NREL. ORNL is managed by UT‐Battelle LLC for DOE under Contract DE‐AC05‐00OR22725. The NMC811 electrodes used in this manuscript were supplied by Argonne's Cell Analysis, Modeling, and Prototyping (CAMP) Facility, which is fully supported by the DOE VTO. The TEM work was carried out by using microscopes that are funded in part by a grant from the Washington State Department of Commerce's Clean Energy Fund. Part of the TEM work was carried out at the William R. Wiley Environmental Molecular Sciences Laboratory, a national scientific user facility sponsored by DOE, Office of Biological and Environmental Research and located at PNNL. PNNL is operated by Battelle for the DOE under Contract No. DE‐AC05‐76RL01830. The views expressed in the article do not necessarily represent the views of the DOE or the U.S. Government. The U.S. Government retains and the publisher, by accepting the article for publication, acknowledges that the U.S. Government retains a nonexclusive, paid‐up, irrevocable, worldwide license to publish or reproduce the published form of this work, or allow others to do so, for U.S. Government purposes.
Keywords
- calendar aging
- cycle life
- energy storage
- lithium-ion battery
- nanoparticle alloys
- silicon anodes