Improved Conductivity of Porous Silicon Electrodes for Rapid Charging of Lithium-ion Batteries

A study conducted by Hiroyuki Kawaura et al. was published in the Journal of Power Sources.

It is necessary to increase the capacity of lithium-ion batteries, and silicon has attracted attention as a new negative electrode material. The silicon electrode leads to a ~10 times increase in the capacity by compared to that of a conventional graphite electrode. Additionally, silicon offers the advantages of low operating voltages, abundance in Earth’s crust, and low toxicity. However, silicon possesses low electrical conductivity and experiences a significant reduction in battery life owing to volume changes during charge–discharge cycling. We developed a method for the mass synthesis of porous silicon using an approach in which aluminum was removed from a precursor consisting of Al–Si alloy powder. This porous silicon experienced a reduced volume change, resulting in increased battery life and capacity. However, its low conductivity remains an issue.
In this study, we focused on transition-metal silicides, which are composed of transition metals and silicon, to improve the electrical conductivity of silicon. We devised a method to disperse silicide inside porous silicon, thereby improving the electrical conductivity of silicon. This achievement is expected to contribute to the high performance of lithium-ion batteries.

Title: Scalable Synthesis of Porous Silicon Electrodes for Lithium-ion Batteries via Acid Etching of Atomized Al–Si Alloy Powders
Authors: Kawaura, H., Suzuki, R., Nagasako, N., Oh-ishi, K.
Journal Name: Journal of Power Sources
Published: May 25, 2024
https://doi.org/10.1016/j.jpowsour.2024.234739