Facile, Water-Based, Direct–Deposit Fabrication of Hybrid Silicon Assemblies for Scalable and High–Performance Li–ion Battery Anodes

Abstract

This study employs water-based electrospinning to directly deposit silicon nanocomposite anode on the copper current collector. This process creates layers of polyvinyl alcohol (PVA) nanofibers filled with silicon nanoparticles (Si NPs) and carbon nanotubes (CNTs), while eliminating conventional slurry steps such as sonication, grinding, ball milling and doctor blading or slot and reverse roll coating. This facile direct deposition approach utilizes water and thus is free of toxic-solvent. Half cells fabricated with these directly deposited nanofibers exhibited an outstanding initial discharge capacity of 4,200mAhg−1 at 0.18Ag−1, which is attributed to the synergic effects of well dispersed Si NPs and CNTs. Composite silicon nanofibers also showed an excellent capacity retention of 93% over 300 cycles at 2.5Ag−1. Furthermore, these nanocomposites have a great performance at fast charge/discharge rates (1193, 945 and 650mAhg−1 at 5, 7.5 and 12.5Ag−1, respectively), due to incorporation of highly conductive CNTs in the nanocomposite matrix. Full cells with LiCoO2 cathode and directly deposited silicon anodes showed no capacity fading when subjected to a cutoff value of 1200mAhg−1anode .These results demonstrate that direct deposition via water-based electrospinning can be an attractive route to the production of high-performance silicon anodes.