Solid-State Electrolytes with Dendrite-Suppressing 3D Nanostructured Interlayers for High-Energy-Density Lithium Metal Batteries

Lithium metal batteries are regarded as the ultimate high-energy-density storage solution for next-generation electric vehicles, yet their commercial viability is severely constrained by uncontrolled lithium dendrite growth, interfacial impedance, and safety hazards with liquid organic electrolytes. This work reports the design and synthesis of a composite solid-state electrolyte (CSSE) incorporating a self-healing 3D boron nitride-doped polymer ceramic matrix. The engineered nanostructured interlayer facilitates uniform lithium-ion flux distribution and accommodates volumetric expansion during continuous charge-discharge cycles. Electrochemical characterization reveals an ionic conductivity of $1.42 \times 10^{-3}\text{ S cm}^{-1}$ at room temperature and a wide electrochemical stability window up to 5.2 V against $\text{Li/Li}^+$. Full-cell configurations paired with high-voltage $\text{LiNi}_{0.8}\text{Co}_{0.1}\text{Mn}_{0.1}\text{O}_2$ (NCM811) cathodes delivered an initial discharge capacity of $208.6\text{ mAh g}^{-1}$ at 0.5C, maintaining 89.4% capacity retention over 800 cycles at elevated current densities without short-circuit failure. These results demonstrate a scalable pathway toward stable, high-capacity, and fire-resistant solid-state energy storage devices.