Stabilizing Electrode-Electrolyte Interphases by Soluble Metal-Organic Polyhedra for High-Performance Lithium-Metal Batteries

Abstract

Lithium metal batteries (LMBs) are promising next-generation technology for achieving energy densities above 400 Wh kg -1 .Paring lithium metal anodes with layered LiCoO 2 (LCO) offers high volumetric energy density for "3C" devices. However, LCO becomes unstable above 4.3 V, causing cobalt dissolution, lattice oxygen loss, and rapid capacity decay. Meanwhile, lithium metal suffers from dendrite growth and electrolyte depletion, compromising safety and cycle life. Herein, a novel class of metal-organic polyhedra (MOPs)-based electrolyte is designed and synthesized to tackle the above issues. On the cathode side, the NAMI-designed MOP (NAMI-MOP) decomposes on the LCO surface, enabling in-situ Cu doping on the LCO particles to protect LCO lattice. On the anode side, it modulates anion reactivity towards lithium metal and form a stable, LiF and lithium (poly)sulfides-rich solid-electrolyte interphase (SEI), suppressing dendrites and enhancing anode stability. Unlike conventional MOPs with poor solubility, the NAMI-MOP dissolves well in both carbonate and ether-based electrolytes, ensuring uniform performance across various cell formats. As the results, cycle life of cells improved from 900 cycles to 2000 cycles at 80% capacity retention at 2C/4C. Pouch cells with NAMI-MOP achieved high energy densities, 362 Wh kg -1 (6.4 Ah Li||LCO) and 412 Wh kg -1 (5.7 Ah Li||NMC811), under lean electrolyte conditions (<1.8 g Ah -1 ), highlighting the promise of MOPs as effective, soluble electrolyte additives for practical LMBs.