Actualizing a High-Energy Bipolar-Stacked Solid-State Battery with Low-Cost Mechanically Robust Nylon Mesh-Reinforced Composite Polymer Electrolyte Membranes

To meet the rapidly growing and diversified demand for energy storage, advanced rechargeable batteries with high-performance materials and efficient battery configuration are widely being exploited and developed. Bipolar-stacked electrode coupling with solid-state electrolytes enables achieving batteries with high output voltage, high energy density, and simple components. Here, a polymer electrolyte membrane is designed with polyethylene oxide containing bis(trifluoromethanesulfonyl)-imide as the electrolyte, succinonitrile as the plasticizer, and nylon mesh as a reinforcement for the bipolar-stacked battery. The as-prepared nylon mesh-reinforced polymer electrolyte membrane shows advantageous features, that is, excellent ionic conductivity (3.38 × 10-4 S cm-1) at room temperature, low interface impedance, and good tolerance against the expansion caused by the plating/stripping of the Li anode and the electrode upon cycling. When used as a polymer electrolyte membrane in the bipolar-stacked battery, the LiFePO4(LFP)-Li4Ti5O12(LTO) cell with three cells connected in series delivers a higher discharge voltage (5.4 V) and a volumetric energy density (0.328 mW h cm-3), nearly 3 times as much as that of the LFP-LTO battery. In addition, LiFePO4-Li pouch cells using the polymer electrolyte membrane can sustain the abuse tests including bending, cutting, and nail penetration well. These results pave a new avenue to develop high-performance polymer electrolyte membranes and allow for the design of high-voltage and volumetric energy density bipolar-stacked batteries.