Laser ablation of pristine Fe foil for constructing a layer-by-layer SiO2/Fe2O3/Fe integrated anode for high cycling-stability lithium-ion batteries

Abstract

In this paper, an integrated SiO₂/Fe₂O₃/Fe anode is fabricated by straightforward laser ablation of the surface of Fe foil in air. The oxidized surface is subsequently coated with tetraethyl orthosilicate (TEOS) and transformed into a SiO₂ layer through a calcination process in an argon atmosphere. The surface oxidation is traced by on-line optical emission spectroscopy (OES) diagnosis. With high electron temperature (∼5200 K) in the laser irradiation zone, the nanostructured Fe₂O₃ layer is formed on the Fe foil, resulting in the pristine Fe₂O₃/Fe anode. This greatly simplified procedure with respect to the conventional route allows direct connection between the Fe₂O₃ layer and the Fe substrate (current collector) without any binder or conductive agent. In addition, the SiO₂ coating layer greatly improves the cycling stability due to the compensatory contribution to capacity during the cycling process and its compatible elasticity to accommodate the volume expansion of Fe₂O₃, which is verified by first-principles theoretical calculations. The integrated SiO₂/Fe₂O₃/Fe anode delivers a stable capacity of 651.7 mA h g⁻¹ at 0.2 A g⁻¹ after 100 cycles. This strategy offers a low-cost route for the rapid fabrication of integrated electrodes, broadening their applications in high cycling-stability LIBs.