표면 엔지니어링을 통한 단일소재 알루미늄 음극의 잠재력 규명

초록

Aluminum (Al) has recently attracted attention as a high-capacity anode for lithium-ion batteries, combining the advantageous properties of lithium metal and silicon anodes. Its high theoretical capacity (~993 mAh g?¹) derived from Li?Al alloying and the excellent electrical conductivity of Al enable a simplified electrode architecture in which the current collector and active material are integrated. In addition, the intrinsically high alloying potential of Al (~0.3 V vs. Li/Li?) effectively suppresses dendrite formation during cycling. These characteristics contribute to enhanced energy density and electrochemical stability. However, conventional Al anodes suffer from rapid capacity fading and poor reversibility caused by non-uniform lithium diffusion, interfacial instability, and mechanical degradation during repeated alloying?dealloying cycles. This study proposes a surface modification strategy combining electrolytic polishing and controlled anodization to mitigate these degradation pathways. The electropolished Al surface provides a smooth and defect-minimized substrate, while the anodized Al₂O₃ layer regulates Li nucleation and suppresses localized stress accumulation. As a result, the modified Al anode exhibits more uniform Li distribution, reduced overpotential, and improved cycling stability compared to bare Al. This study demonstrates that chemical and structural control of the Al surface can simultaneously enhance the electrochemical reversibility and mechanical stability of Al anodes, proposing a scalable design direction for high-capacity anodes in next-generation high-energy-density lithium batteries.