The spontaneous cascade optimization strategy of the double enrichment improves anion-derived solid electrolyte interphases to enable stable lithium-metal batteries

Abstract

Anion regulation represents a highly effective, convenient, and economical approach to generate LiF-rich solid electrolyte interfaces (SEIs). The anion decomposition process is influenced by charge density and anion concentration. However, current research primarily concentrates on increasing charge density to enhance anion decomposition. Herein, the spontaneous cascade optimization strategy driven by the double enrichment of anions and charges is proposed by utilizing NH₂-MIL-101(Fe)@Copc (MOF@Copc). Specifically, NH₂-MIL-101(Fe) functions as a TFSI⁻ anion trap via the Lewis acid–base interactions and synergistic hydrogen bonding, thereby achieving primary optimization. Subsequently, the rich electronic structure of Copc facilitates charge delocalization and lowers the energy barrier for anion decomposition, allowing the C–F bonding to break more readily, thereby enabling further optimization. The π–π stacking interaction between the MOF and Copc facilitates the close association of adsorption and catalytic sites, allowing the continuous breakdown of the C–F series products in a chain reaction. The assembled LFP (19.26 mg cm⁻²) demonstrates a commercial-grade cathode area capacity, maintaining over 90% capacity retention across 350 cycles at 1C, with a capacity decay rate of only 0.02% per cycle. More importantly, this strategy enables the industrial-scale production of Ah-class anode-free lithium-metal pouch batteries exceeding 300 W h kg⁻¹. Optimizing anion decomposition provides a novel perspective to advance the practical application of lithium-metal batteries.