Tuning electrochemical performance of Si-based anodes for lithium-ion batteries by employing atomic layer deposition alumina coating

Abstract

Si-based anode materials were prepared by electrospinning and carbonization using polyacrylonitrile as the spinning medium and carbon precursor. The effects of atomic layer deposition (ALD) alumina coatings with different thicknesses on the electrochemical performance of Si/C composite nanofiber anodes were investigated. Results show that when the ALD alumina coating cycle number is 28, the capacity retention at 100th cycle increases significantly from 36.1% to 82.3% and the coulombic efficiency increases from 98.4% to 99.9%, compared to those of the uncoated Si/C nanofiber anode. This demonstrates the excellent stability of ALD alumina-coated Si/C composite nanofiber anodes. The enhanced electrochemical performance is mainly due to the protective effect of conformal ALD alumina coating, which could improve the mechanical integrity of the electrode structure and prevent the side reactions between the electrode and the electrolyte.