Ion-Exchange-Induced Phase Transition Enables an Intrinsically Air Stable Hydrogarnet Electrolyte for Solid-State...

Area of Science:

• Materials Science
• Electrochemistry
• Energy Storage

Background:

• Garnet electrolytes face challenges with air stability, hindering their use in large-scale energy storage.
• Developing stable electrolytes is crucial for advancing solid-state lithium batteries (SSLBs).

Purpose of the Study:

• To develop a garnet-based electrolyte with significantly improved air stability.
• To enable large-scale, eco-friendly fabrication of stable composite electrolytes for SSLBs.

Main Methods:

• An ion-exchange-induced phase transition was used to create a hydrated hydrogarnet electrolyte from conventional garnet.
• The hydrogarnet's structure and ion conduction pathways were analyzed.
• The electrolyte's stability, ionic conductivity, electrochemical window, and lithium transference number were evaluated.
• SSLBs utilizing the hydrogarnet electrolyte were fabricated and tested for performance.

Main Results:

• The hydrogarnet electrolyte demonstrated over two years of air stability.
• It possesses intrinsic air stability due to the elimination of air-sensitive lithium ions and unobstructed conduction paths.
• Comparable ionic conductivity to traditional garnet was achieved.
• High ionic conductivity (8.04 × 10^-4 S cm^-1), a wide electrochemical window (4.95 V), and a high lithium transference number (0.43) were recorded.
• SSLBs showed impressive capacity (164 mAh g^-1) and cycle life (89.6% retention after 180 cycles).

Conclusions:

• A novel hydrogarnet electrolyte with exceptional air and lithium metal stability was successfully designed.
• This work presents an eco-friendly and scalable aqueous route for fabricating stable composite electrolytes for SSLBs.
• The developed hydrogarnet electrolyte is a promising candidate for next-generation energy storage systems.