Organic montmorillonite modified polyethylene oxide based polymer electrolyte for dendrite-free flexible solid-state lithium metal batteries

Polyethylene oxide (PEO) based solid-state electrolytes are known for the low manufacturing cost and excellent processability, but their practical application is paved with thorns including the inferior ionic conductivity, low Li + transfer number and insufficient Li dendrite blocking ability. Herein, we propose organic montmorillonite (OMMT) with expanded layer spacing (1.97 nm) as versatile fillers to construct PEO-OMMT electrolyte, in which OMMT not only increases Li + transfer number (0.56) and ionic conductivity (7.15 × 10 −4  S cm −1 ), providing fast ionic transport channels, but also endows PEO with high mechanical strength, resulting remarkable Li dendrite blocking ability (>2100 h). Additionally, the high dielectric constant and Lewis-rich polar sites of OMMT facilitate the dissociation of lithium salts and the rapid formation of LiF and Li 3 N-rich solid electrolyte interface layers. Impressively, the LiFePO 4 | PEO-OMMT | Li cell shows a high initial capacity (154.4 mAh g −1  at 0.5C) with ultralong cycling lifespan (>1200 cycles). Similarly, the LiNi 0.83 Mn 0.05 Co 0.12 O 2 | PEO-OMMT | Li cell retains a high discharge capacity of 151.5 mAh g −1 after 100 cycles at 0.2C. This work highlights the indelible contributions of OMMT functionalized fillers in improving the interfacial stability of PEO based solid-state electrolytes, paving a feasible avenue for the practical application of solid-state lithium metal batteries.