Selective nucleation and targeted deposition effect of lithium in a lithium-metal host anode

Abstract

Uncontrollable lithium (Li) nucleation and growth on Li-anode surfaces is considered to be the main reason for the rapid failure of Li-metal batteries. However, the underlying mechanism is still poorly understood. Here, we show selective nucleation and a targeted deposition effect of Li in specially designed macropores, and reveal that such behavior is closely dependent on the pore size and local lithiophilicity, using density functional theory calculations. It is revealed that fluoride-rich carbon fibers with interconnected macropores (>50 nm) can serve as stable Li-ion flow rails to induce Li-nucleation and deposition until they are completely filled with Li-metal. Practically speaking, when directly using these Li-filled carbon fibers with a small capacity of 10 mA h cm⁻² as anodes and when pairing with high voltage LiNi_0.8Co_0.15Al_0.05O₂ cathodes, the batteries exhibit significantly enhanced stability and coulombic efficiency even under highly challenging conditions, including a small electrolyte amount of 6 μL mg⁻¹ and a high cathode loading of 7 mg cm⁻². This work helps in the elucidation of the Li-nucleation and deposition behaviors and provides a promising strategy for designing reliable Li-host anodes.