Polydopamine-Derived Nitrogen-Doped Carbon-Coated Dendritic Fibrous Nanosilica/Graphene Composites as High-Performance Anodes for Lithium-Ion Batteries

The derivative of silicon, silicon dioxide (SiO2), has become a promising candidate material to address the limitations of graphite and pure silicon anodes. However, its volume change during cycling and lack of electronic conductivity lead to significant performance limitations. In this research, polydopamine-derived nitrogen-doped carbon-coated dendritic fibrous nanosilica/graphene composites (DFNS@C/rGO) are obtained by in situ polymerization of dopamine combined with high-temperature carbonization. Utilizing the excellent adhesion ability of polydopamine, nitrogen-doped carbon coating is successfully completed on the dendritic fibrous structure of DFNS. This nitrogen-doped carbon coating permeating into the structure adjusts the pore structure of DFNS, increases the specific surface area of DFNS, and optimizes the contact mode between the material and the electrolyte (forming a more stable SEI film significantly improves the electrochemical reaction reversibility and structural stability). Combined with graphene, the electronic conductivity of the material is improved, and the volume expansion of the material is effectively inhibited. DFNS@C/rGO has a high specific capacity of 729 mAh g–1 after 100 cycles at a current density of 100 mA g–1. At the same time, it has a rate performance of 330 mAh g–1 at 1000 mA g–1.