Dealloying of modified Al-Si alloy to prepare porous silicon as Lithium-ion battery anode material

ABSTRACT

Silicon plays an important role in the development of high-energy Lithium-ion batteries. However, the high volume expansion rate (>300%) makes it a commercially unfeasible independent Lithium-ion battery anode material. In this work, we adopt P and Sr complex modification and increase the cooling rate to refine the microstructure of Casting Al-20Si alloy, then acid etching Al-20Si alloy ingot to prepare porous silicon. The as-prepared silicon has a three-dimensional dendritic porous structure based on the SEM morphology characterization. The porous silicon electrode was prepared with Si powder: acetylene black: binder in a ratio of 2:1:1. The electrolyte solution was 1 M LiPF6/EC:EMC: DMC = 1:1:1 (V/V) with or without 5% FEC. In the electrolyte solution without 5% FEC, the first charge and discharge capacities of the porous silicon electrode are 2924.8 mAh/g and 1910.1 mAh/g, and the coulombic efficiency is about 65.31%. In the electrolyte solution with additive 5% FEC, the first charge and discharge capacities are 3444.6 mAh/g and 2469.5 mAh/g, respectively. Its first cycle coulombic efficiency is 72.19%. After adding 5% FEC into the electrolyte, the main component of SEI film is the decomposition product of FEC, which can effectively inhibit the decomposition of electrolyte solvent at a low potential and improve the specific capacity of the battery.

KEYWORDS:

• Casting Al-20Si alloy
• P and Sr complex modification
• acid etching
• porous Si
• Lithium-ion battery

Acknowledgments

The authors are thankful for the financial support from the Natural Science Foundation of Shandong Province (NO. ZR2020ME108).

The authors are thankful for the financial support from the Major Science and Technology Innovation Project of Tai'an (city in Shandong Province)[NO. 2021ZDZX017].

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

This work was supported by the Natural Science Foundation of Shandong Province [NO. ZR2020ME108].This work was supported by the Major Science and Technology Innovation Project of Tai'an (city in Shandong Province)[NO. 2021ZDZX017].