Rigid and Flexible Component Combined Si@g-C₃N₄/C: A Synergistic Strategy for Constructing Robust Structure to Enhance the Cyclic Stability of the Silicon Anodes.

Abstract

The practical application of high-capacity silicon is hindered by severe volume variation during cycling. Herein, a synergistic strategy integrating rigid and flexible components is proposed to construct a Si@g-C₃N₄/C composite with a robust structure. The rigid component, glucose-derived carbon, forms an outer protective layer and an inner conductive network, avoiding direct electrolyte contact and providing sufficient conductivity. The embedded flexible component, g-C₃N₄, further enhances the deformation resistance (mechanical properties) of the composite and maintains the structure's stability. Si@g-C₃N₄/C maintains a reversible capacity of 722.8 mAh g^-1 after 150 cycles at 0.2 A g^-1 and 478.2 mAh g^-1 after 600 cycles at 1 A g^-1, with capacity retentions of 80.4% and 98.5%, respectively. It can still release a reversible capacity of 174.1 mAh g^-1 at 3 A g^-1. These results demonstrate that the synergistic combination strategy of rigid and flexible components significantly enhances the electrochemical performance of Si-based anodes.