Preparation of nanostructured silicon by low-temperature aluminothermic reduction of clay minerals as anode material for high-performance lithium-ion batteries

D Shen and JQ Niu and ZQ Ren and R Zhang and D Xia and YZ Yang and W Dong and SB Yang, JOURNAL OF ENERGY STORAGE, 131, 117493 (2025).

DOI: 10.1016/j.est.2025.117493

Silicon has been widely recognized as one of the most attractive anode candidates in the next generation of lithium-ion batteries due to its excellent theoretical specific capacity, low operating voltage, and extensive sources. Herein, one-dimensional tubular silicon and two- dimensional lamellar silicon with porous structures have been successfully synthesized from low-cost and resource-rich clay minerals (halloysite, kaolin, chlorite and dickite) as raw materials through the low-temperature aluminothermic molten salt reduction process. The results show that the morphology and microstructure of nanostructured silicon depend largely on the morphology and microstructure of its precursor, i.e., one-dimensional tubular silicon from halloysite, two- dimensional lamellar silicon from kaolin, chlorite and dickite. When used as an anode for lithium-ion batteries, one-dimensional tubular Si derived from natural halloysite exhibits superior electrochemical performance, with an initial discharge capacity of 2675 mAh g-1 and an initial coulombic efficiency of 86 %. It yields a high reversible capacity of 1418 mAh g-1 at 0.2 A g-1 after 400 cycles with a capacity retention of 53 %. The voltage and Si-Li chemical bond state of elemental silicon during charge and discharge were studied through molecular dynamics and first-principles calculations. It was found that electrons from Li atoms transferred to nearby Si atoms, and with the increase of Li content, the ionic bond properties of Si-Li bonds increased, resulting in a decrease in Young's modulus and an increase in tensile fracture. This work provides a facile and cost-effective approach for the preparation of nanostructured silicon from natural clay minerals as high-performance silicon anode materials.

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