Honeycomb-kagome FSL-graphene: A carbon allotrope as an ultra-high capacity anode material for fast-rechargeable sodium-ion battery.

This article focuses on the theoretical design and evaluation of fish-scale-like graphene (FSL-graphene), a two-dimensional (2D) carbon allotrope combining honeycomb and kagome lattice structures, as a promising anode material for sodium-ion batteries (SIBs). FSL-graphene demonstrates excellent energetic, dynamic, thermal, and mechanical stability, a narrow indirect bandgap of 0.33 eV, and high carrier mobilities. It exhibits an ultra-high theoretical sodium storage capacity of 3347.1 mA h g⁻¹, low sodium diffusion energy barriers (0.19–0.23 eV), a moderate average open-circuit voltage (~0.598 V), and minimal lattice changes (~1.3%) during sodiation, indicating good cycling stability. The study also highlights that electrolytes with high dielectric constants, such as ethylene carbonate, enhance sodium adsorption and migration on FSL-graphene, supporting its potential application in large-scale energy storage.