Ceramic-Fiber Solid-State Electrolyte Membrane for Dendrite Resistance

The patent applies composite materials by combining solid-state electrolyte with ceramic fibers (such as Al2O3, SiO2, Si3N4, or SiC) to create a composite solid-state electrolyte membrane. The ceramic fibers are dispersed in the solid-state electrolyte at a concentration of 0.1-10 wt%, forming a composite structure that leverages the safety benefits of solid-state electrolytes while gaining the fracture resistance of ceramic fibers. This composite approach directly resolves the contradiction by maintaining the non-flammable, non-corrosive properties of solid-state electrolytes while significantly improving fracture toughness to prevent short-circuits during fast charging.

The patent applies local quality by strategically distributing ceramic fibers within the solid-state electrolyte matrix. The ceramic fibers are not uniformly mixed at the molecular level but are instead dispersed as discrete reinforcing phases throughout the electrolyte. This localized reinforcement creates regions of enhanced fracture toughness precisely where needed to resist crack propagation during dendrite formation and fast charging stress, while maintaining the overall ionic conductivity of the solid-state electrolyte.

The composite structure of solid-state electrolyte with dispersed ceramic fibers enhances critical current density by providing a more robust interface for lithium ion deposition. The ceramic fibers create a tortuous path that promotes uniform lithium deposition and prevents dendrite penetration, thereby increasing the critical current density threshold before short-circuit occurs. This allows the battery to maintain high energy density while safely supporting fast charging operations.

The ceramic fibers act as an intermediary structure between the solid-state electrolyte and lithium ions during charging. They provide nucleation sites that guide uniform lithium deposition and prevent direct contact between lithium dendrites and the electrolyte interface, thereby mediating the charging process to achieve higher critical current density without short-circuiting.

The patent applies preliminary action by pre-dispersing ceramic fibers into the solid-state electrolyte powder mixture before sintering. The ceramic fiber powder is mixed with the solid-state electrolyte powder using conventional mixing techniques, and then the mixture is pressed and sintered in one integrated process. This preliminary dispersion step simplifies manufacturing compared to post-processing fiber insertion, as it incorporates the reinforcement phase during the standard solid-state electrolyte fabrication process.

The patent applies parameter changes by optimizing the ceramic fiber concentration range (0.1-10 wt%) and aspect ratio (L/D ≥ 5) to achieve sufficient fracture toughness improvement while maintaining manufacturability. By establishing specific parameter ranges, the patent balances performance enhancement with manufacturing simplicity, avoiding excessive fiber loading that would complicate processing or degrade ionic conductivity.