Regulating Lithium-Ion Transport in PEO-Based Solid-State Electrolytes through Microstructures of Clay Minerals
Wankai Wang, Yanfei Yang, Junping Zhang
Abstract
Clay minerals show significant potential as fillers in polymer composite solid electrolytes (CSEs), whereas the influence of their microstructures on lithium-ion (Li + ) transport properties remains insufficiently understood. Herein, we design advanced poly(ethylene oxide) (PEO)-based CSEs incorporating clay minerals with diverse microstructures including 1D halloysite nanotubes, 2D Laponite (Lap) nanosheets, and 3D porous diatomite. These minerals form distinct Li + transport pathways at the clay-PEO interfaces due to their varied structural configurations. Among them, 2D Lap nanosheets exhibit the most significant improvements in Li + conductivity (1.67 × 10 –4 ± 0.02 × 10 –4 S cm –1 at 30 °C), Li + transference number (0.72), and oxidative stability (4.7 V). Consequently, a solid-state Li|LiFePO 4 battery with the PEO/Lap CSE exhibits high reversible capacity and superior cycling stability (with 90.2% capacity retention after 250 cycles at 1.0 and 30 °C). Furthermore, pouch batteries with an integrated LiFePO 4 cathode and PEO/Lap CSE show superior safety performance, even under extreme damage. This work provides valuable theoretical insights for the design and application of clay mineral fillers in CSEs.