Synergistic Modulation of Boron Doping and Built-In Electric Field Engineering for Optimizing the Performance of β-B ₂ C ₁₆ as a Sodium-Ion Battery Anode

The strategies for modulating anode are crucial for advancing metal-ion batteries. Through first-principles calculations, we propose a promising anode for sodium-ion batteries named β-B2C16, which exhibits an exceptionally low diffusion barrier (0.08 eV), a high theoretical storage capacity (627.4 mA h g–1), and a low average open-circuit voltage (0.24 V). Beyond these intrinsic merits, we further propose a heterojunction-based design strategy to effectively analogue to the influence of an external electric field (−0.032 V/Å). The β-B2C16/graphene+ heterojunction produces an effect of enhanced adsorption strength for Na (from −1.34 to −2.78 eV) and reduced diffusion barriers (from 0.08 to 0.042 eV). This approach of leveraging heterojunction effects to emulate field-induced modulation offers a pathway for dynamically optimizing anode performance, shifting from static material design toward tunable electrochemical behavior.