Suppressing electrolyte-lithium metal reactivity via Li ⁺-desolvation in uniform nano-porous separator

Abstract

Lithium reactivity with electrolytes leads to their continuous consumption and dendrite growth, which constitute major obstacles to harnessing the tremendous energy of lithium-metal anode in a reversible manner. Considerable attention has been focused on inhibiting dendrite via interface and electrolyte engineering, while admitting electrolyte-lithium metal reactivity as a thermodynamic inevitability. Here, we report the effective suppression of such reactivity through a nano-porous separator. Calculation assisted by diversified characterizations reveals that the separator partially desolvates Li ⁺ in confinement created by its uniform nanopores, and deactivates solvents for electrochemical reduction before Li ⁰-deposition occurs. The consequence of such deactivation is realizing dendrite-free lithium-metal electrode, which even retaining its metallic lustre after long-term cycling in both Li-symmetric cell and high-voltage Li-metal battery with LiNi _0.6Mn _0.2Co _0.2O ₂ as cathode. The discovery that a nano-structured separator alters both bulk and interfacial behaviors of electrolytes points us toward a new direction to harness lithium-metal as the most promising anode.

Abstract

Lithium dendrite and parasitic reactions are two major challenges for lithium metal anode. Here, the authors show suppression of lithium-dendrite and elimination of continuous parasitic reactions by tuning the reduction kinetics of lithium-ion through a uniform nano-porous separator.