Lithium metal is considered the most promising anode materials for next-generation high energy density batteries (e.g., solid state batteries, Li metal batteries, Li-sulphur batteries, Li-oxygen bateries), benefiting from its very high theoretical capacity (3860 mAh/g) and very low reduction potential (-3.04V). However, the formation and growth of Li dendrite during the repeated charge and discharge process cause significant capacity fade, short circuit, and fatal failure of batteries [1,2]. The safety of Li batteries can be enhanced by modification of the copper current collector and introduction of interlayer materials, to alter the Li nucleation process and suppress dendrite formation at the metal anode-electrolyte interfaces [3,4].

In this talk, I will introduce our efforts in using computational modelling to help design the metal anode-electrolyte interfaces. First-principle density functional theory calculations are used to investigate Li deposition on 19 interlayer metals [4]. A relationship between the Li deposition overpotential and diffusion barriers is established to help identify interlayer metals and alloys that can enable efficient Li deposition. We also collaborate with experimental partners to design a Sn-modified copper substrate, which forms alloying reaction with Li to yield a deposition interlayer composed of Sn and Li-Sn intermetallics that regulates both Li diffusivity and adsorption during initial deposition, leading to enhanced battery performance. Finally, we combine fine-tuned machine-learning interatomic potentials (MLIP) with large-scale molecular dynamics (MD) simulations to resolve the atomistic pathways of lithium alloying and crystallization on Cu and interlayer metals. Zn and Mg show alloy-mediated crystallization process to enhance lithium diffusion and structural uniformity, whilst the Li nucleation on Cu and the formation of intermetallic alloys with Bi are revealed. These results are validated by experimental observations through scanning electron microscopy, X-ray diffraction, atomic force microscopy, and time-of-flight elastic recoil detection corroborates the predicted alloying and phase evolution. The MLIP enhanced MD simulations are also performed for metal anode-solid state electrolytes (SSEs), revealing the formation of different interphase compounds when different SSEs and different interlayer metals are used. Our modelling framework can help design metal interlayers for regulating lithium nucleation and enabling safe operation of next-generation lithium batteries.