Biomimetics-Driven Design of Micron-Sized SiO Composites for High-Performance Lithium-Ion Batteries

Abstract

Micron-sized SiO-based materials have attracted extensive attention in lithium-ion batteries due to high theoretical capacity and low-cost. However, their development is seriously hampered by the large volume change and low conductivity of SiO. Herein, by combining the theoretical prediction with biomimetics-driven design concept, a unique chloroplast-like SiO@N-doped carbon-carbon coated SnO₂ (denoted as SiO-NC@SnO₂-C) integrative composite is presented through a facile one-pot hydrothermal route. The resultant SiO-NC@SnO₂-C anode for lithium-ion storage shows a high reversible capacity of 1209 mA h g⁻¹ at 0.2 A g⁻¹ after 160 cycles and an outstanding rate capability of 722.7 mA h g⁻¹ at 5 A g⁻¹. In situ TEM technique and cross-sectional SEM images reveal that the cavity formed in the composite, the flexible carbon interlayer, and glucose-derived carbon outer layer together play crucial roles in alleviating the volume expansion and improving the structural stability of the electrode. In situ Raman spectra further verify that the highly reversible structure of SiO-NC@SnO₂-C is responsible for its superior stability. Importantly, the SiO-NC@SnO₂-C composite also shows an excellent reversible lithium storage capacity of 92.9 mA h g⁻¹ with a 73% of capacity retention after 100 cycles at 1 C in full-cells.