Halide Electrolytes for All-Solid-State Sodium Batteries: From Fundamental Chemistry to Interface Engineering

Area of Science:

• Materials Science, Electrochemistry, Energy Storage

Background:

• All-solid-state sodium batteries (ASSSBs) offer a safer, sustainable alternative to conventional lithium-ion batteries.
• Halide solid electrolytes are key components in ASSSBs, providing good ionic conductivity and mechanical properties.
• Challenges remain in synthesis, performance optimization, and understanding ion transport and interfaces.

Purpose of the Study:

• To provide a comprehensive review of sodium-based halide electrolytes for ASSSBs.
• To establish structure-property relationships for rational material design.
• To offer design principles and a roadmap for accelerating ASSSB commercialization.

Main Methods:

• Comprehensive literature review covering structural chemistry, ion transport, synthesis, modification, and electrochemical properties.
• Analysis of interfacial behavior and computational insights.
• Systematic framework for understanding synthesis-structure-property relationships.

Main Results:

• Detailed insights into Na-halide conductor design principles, including humidity stability.
• Correlations established between interphases, degradation modes, and full-cell performance metrics.
• Assessment of key performance metrics (energy density, power density, cycle life) and design guidance.

Conclusions:

• Sodium-based halide electrolytes are promising for ASSSBs but face challenges like moisture sensitivity and anode incompatibility.
• Rational material design, interface engineering, and scalable manufacturing are crucial for commercialization.
• Further research focusing on advanced characterization and standardized metrics is needed.