High-Yield Synthesis of Battery-Grade Silicon from Halloysite Through HF-Free Metallothermic Reduction
- 1Department of Chemical and Biological Engineering, Brigham Young University, Provo, UT 84602, USA
- 2Department of Electrical and Computer Engineering, Brigham Young University, Provo, UT 84602, USA
Abstract
Magnesiothermic reduction is a promising route for synthesizing nanostructured silicon for battery anodes, yet commercial scalability is hindered by highly exothermic reaction conditions and reliance on hydrofluoric acid (HF) for purification. Here, it is demonstrated that intrinsic thermal accumulation during bulk synthesis drives the formation of magnesium silicate. To counteract this effect, a binary calcium chloride–magnesium chloride salt mixture was used as an intrinsic heat sink. By tuning its liquidus temperature to 675 °C, the reaction exotherm was absorbed via latent heat of fusion, preventing byproduct formation without microreactor geometries. Furthermore, an optimized ethanol-based purification protocol was developed to suppress surface silicon oxidation. This suppression circumvented the need for HF etching to remove unreacted surface oxides, resulting in a final silicon yield of approximately 93%. Additionally, powder X-ray diffraction is established as a predictive, high-throughput screening tool; the intensity of the amorphous scattering peak reliably correlates with surface oxide thickness and subsequent electrochemical failure. Ultimately, the fully optimized, HF-free silicon demonstrated sustained cyclability and capacity retention comparable to traditional HF-etched baselines. By resolving thermal scaling limits and surface oxide formation, this work establishes a high-yield and HF-free pathway for the commercial manufacturing of silicon anode active material.
Related
- Highly Luminescent Alkyl- and Alkoxy-Terminated Silicon Quantum Dots via Aging Following Single-Step Plasma Synthesis and Functionalization
- Synthesis of polymer-derived graphene/silicon nitride-based nanocomposites with tunable dielectric properties
- Surface Phosphorus-Modified Mo2C MXene Toward Boosted Oxygen Reduction Reaction for Mg–Air Battery
- Rapid One-Step Synthesis of Sodium-Ion Battery Cathodes from Desalination Waste: A Sustainable Approach to High-Performance Energy Storage
- Highly Luminescent Alkyl- and Alkoxy-Terminated Silicon Quantum Dots via Aging Following Single-Step Plasma Synthesis and Functionalization
BibTeX
@article{manwaring2026highyield,
title = {{High-Yield Synthesis of Battery-Grade Silicon from Halloysite Through HF-Free Metallothermic Reduction}},
author = {Kyle Charles Manwaring and Jaeseok Kim and Lizbeth Zurita-Garcia and Brian Anthony Mazzeo and Dean Richard Wheeler},
journal = {Batteries},
year = {2026},
month = oct,
doi = {10.3390/batteries12100407},
url = {https://www.mdpi.com/2313-0105/12/10/407},
note = {CC BY 4.0},
}
RIS
TY - JOUR
TI - High-Yield Synthesis of Battery-Grade Silicon from Halloysite Through HF-Free Metallothermic Reduction
AU - Kyle Charles Manwaring
AU - Jaeseok Kim
AU - Lizbeth Zurita-Garcia
AU - Brian Anthony Mazzeo
AU - Dean Richard Wheeler
PY - 2026
DA - 2026/10/08
JO - Batteries
DO - 10.3390/batteries12100407
UR - https://www.mdpi.com/2313-0105/12/10/407
AB - Magnesiothermic reduction is a promising route for synthesizing nanostructured silicon for battery anodes, yet commercial scalability is hindered by highly exothermic reaction conditions and reliance on hydrofluoric acid (HF) for purification. Here, it is demonstrated that intrinsic thermal accumulation during bulk synthesis drives the formation of magnesium silicate. To counteract this effect, a binary calcium chloride–magnesium chloride salt mixture was used as an intrinsic heat sink. By tuning its liquidus temperature to 675 °C, the reaction exotherm was absorbed via latent heat of fusion, preventing byproduct formation without microreactor geometries. Furthermore, an optimized ethanol-based purification protocol was developed to suppress surface silicon oxidation. This suppression circumvented the need for HF etching to remove unreacted surface oxides, resulting in a final silicon yield of approximately 93%. Additionally, powder X-ray diffraction is established as a predictive, high-throughput screening tool; the intensity of the amorphous scattering peak reliably correlates with surface oxide thickness and subsequent electrochemical failure. Ultimately, the fully optimized, HF-free silicon demonstrated sustained cyclability and capacity retention comparable to traditional HF-etched baselines. By resolving thermal scaling limits and surface oxide formation, this work establishes a high-yield and HF-free pathway for the commercial manufacturing of silicon anode active material.
SN - 2313-0105
ER -