Transference Number Reinforced-Based Gel Copolymer Electrolyte for Dendrite-Free Lithium Metal Batteries

The progress of electric vehicles is highly inhibited by the limited energy density and growth of dendrite Li in current power batteries. Breakthroughs and improvements in electrolyte chemistry are highlighted to directly address the above issues, namely, the development of electrolytes with a high lithium-ion transference number (t_Li⁺), enabling one to effectively restrict the concentration polarization during repetitious cycling. Herein, we propose a novel ether-based copolymer-based gel polymer electrolyte (ECP-based GPE) by in situ copolymerization as an intriguing strategy to achieve a high t_Li⁺ of ∼0.64. Molecular dynamics simulations and finite element method analyses illustrate the enhanced Li⁺ diffusion process (D_Li⁺, ∼1.76 × 10^-10 m² s^-1) in ECP-based GPE with a homogeneous electric potential accommodated around the lithium metal anode. Therefore, such a high-t_Li⁺-based electrolyte renders a high reversibility of dendrite-free lithium plating/stripping at a high areal capacity (5 mA cm^-2/5 mA h cm^-2) in an Li||Li symmetric cell and facilitates superior cycling performances (over 1000 cycles) at a high rate (5 C) with a capacity retention of ∼91.1% in Li||LiFePO₄ batteries, promoting the practical application of solid-state lithium metal batteries.