Multiple-crosslinking-reinforced ionogel electrolytes for safe and high-performance quasi-solid-state lithium metal batteries

Abstract

Quasi-solid polymer electrolytes (QSPEs) are promising electrolytes for next-generation high-energy-density lithium metal batteries, benefiting from their flexibility and intimate interfacial contact with electrodes. However, conventional QSPEs encounter challenges such as limited Li+ mobility and poor mechanical properties. Herein, we design a multiple-crosslinked ionogel electrolyte, featuring a high Li+ transference number of 0.74, superior stability against oxidation of 4.8 V, and high mechanical strength (0.8 MPa) simultaneously. The ionogels electrolytes construct rapid Li+ conductive pathways and promote the formation of lithium fluoride (LiF), lithium nitride (Li3N), and lithium sulfide (Li2S)-enriched passivation layer during Li deposition, greatly enhancing the reversibility of lithium metal deposition. Consequently, the Li||Li cell demonstrates superior lithium plating/stripping stability for 5000 h, and the Li||LiFePO4 cell shows stable cycling performance with 80% capacity retention after 1000 cycles at a rate of 0.5 C. Remarkably, the high-voltage Li||NCM532 cell maintains about 76% of its capacity over 200 cycles at 4.2 V.