2025 AIChE Annual Meeting

Composite Solid-State Electrolytes for Safer, High-Performance Lithium Batteries

The global transition toward renewable energy demands advanced storage systems that are safe, scalable, and deliver higher energy density than conventional lithium-ion batteries (LIBs). While LIBs dominate current markets, their reliance on flammable liquid electrolytes and capacity-limited graphite anodes imposes intrinsic constraints on safety and performance. Solid-state batteries (SSBs) overcome these barriers by replacing liquid electrolytes with solid-state electrolytes (SSEs), enabling safer operation, greater thermal stability, and the integration of high-capacity anodes such as lithium metal and silicon.

This research focuses on engineering composite SSEs that optimize ionic conductivity while maintaining stable electrode to electrolyte interfaces. The NASICON-type ceramic lithium aluminum germanium phosphate (LAGP) serves as the primary inorganic framework owing to its high lithium-ion conductivity and chemical stability. To address LAGP’s brittleness and poor processability, it is integrated with polymeric binders—including polyacrylonitrile (PAN), polyethylene oxide (PEO), and polyvinylidene fluoride (PVDF)—to enhance flexibility, mechanical integrity, and interfacial contact. Parallel studies explore polyethylene glycol (PEG) and sulfide-based Li₆PS₅Cl (LiPSCl) as alternative phases offering high ionic transport and scalable fabrication potential.

Electrochemical performance is characterized using impedance spectroscopy, galvanostatic cycling, and linear sweep voltammetry to assess ionic transport, interfacial resistance, and cycling stability. Complementary structural and compositional analyses are conducted through X-ray diffraction (XRD), scanning electron microscopy with energy-dispersive spectroscopy (SEM–EDS), and time-of-flight secondary ion mass spectrometry (TOF–SIMS). Preliminary results indicate that composite electrolytes preserve crystalline stability during thermal processing and exhibit uniform elemental distribution, though surface densification and heterogeneity at particle interfaces suggest avenues for further optimization.

By systematically tuning composite architecture, polymer chemistry, and processing parameters, this work aims to design SSEs that achieve high ionic conductivity, mechanical resilience, and stable interfaces suitable for integration into full-cell configurations with commercial cathodes. The resulting materials advance the development of safe, high-performance SSBs critical to electric vehicles, consumer electronics, and renewable energy storage applications.