Stable High-Capacity Lithium Ion Battery Anodes Produced by Supersonic Spray Deposition of Hematite Nanoparticles and Self-Healing Reduced Graphene Oxide

Hematite (Fe₂O₃) nanoparticles and reduced graphene oxide (rGO) were supersonically sprayed onto copper current collectors to create high-performance, binder-free lithium ion battery (LIB) electrodes. Supersonic spray deposition is rapid, low-cost, and suitable for large-scale production. Supersonic impact of rGO sheets and Fe₂O₃ nanoparticles on the substrate produces compacted nanocomposite films with short diffusion lengths for Li⁺ ions. This structure produces high reversible capacity and markedly improved capacity retention over many cycles. Decomposition of lithium oxide generated during cycling activates the solid electrolyte interface layer, contributing to high capacity retention. The optimal composition ratio of rGO to Fe₂O₃ was 9.1 wt.%, which produced a reversible capacity of 1242 mAh g⁻¹ after N = 305 cycles at a current density of 1000 mA g⁻¹ (1C).