Stable 15-Ah Anode-Free Li Pouch Cell Enabled by Electron Resonance Effect

Abstract

Ah-level anode-free Li metal batteries (AFLMBs) exhibit the highest theoretical energy density for rechargeable batteries; however, their practical application is hindered by serious electrolyte depletion and active Li consumption. The insufficiently protective solid electrolyte interphase (SEI) limits the Li retention during the prolonged cycling. Here we establish two criteria, i.e., electron resonance energy and exchange repulsion energy, using the principle of electron resonance to facilitate the formation of stable SEI with high content of anion reduction products. Based on this principle, fractional electron transfer from anions to solvent molecules helps decrease the electron density around the anions, thereby facilitating the preferential reduction of anions. This electron resonance mechanism effectively promotes the incorporation of anion-decomposition products into the SEI, mitigating electrolyte consumption and dead Li formation. Additionally, battery stability is improved through the anode-free configuration in the optimized electrolyte due to the reduced galvanic corrosion and Li metal inventory. Using an electrolyte enlighted by electron resonance effect, an anode-free Cu||LiNi_0.8Mn_0.1Co_0.1O₂ pouch cell with a 15-Ah capacity was assembled, achieving a high energy density of 500 Wh kg^-1 with excellent reversibility. This study offers insights into advanced electrolyte design, focusing on anion-decomposed interphase to boost the stable application of Ah-level AFLMBs.