Working Aqueous Zn Metal Batteries at 100 °C

Area of Science:

• Electrochemistry
• Materials Science
• Energy Storage

Background:

• High-temperature power supplies are crucial for expanding electric device applications.
• Aqueous zinc metal batteries (ZMBs) offer intrinsic safety for high-temperature energy storage.
• Limited research exists on the reversibility and cycling stability of aqueous ZMBs above 100 °C.

Purpose of the Study:

• To investigate the limitations of traditional aqueous ZMBs at high temperatures (≥100 °C).
• To develop a novel electrolyte enabling stable and reversible operation of ZMBs at extreme temperatures.
• To demonstrate the potential of ZMBs for reliable high-temperature energy storage.

Main Methods:

• Introduction of 1,5-pentanediol as a crowding agent into an aqueous electrolyte.
• Electrochemical characterization of Zn//Zn symmetric cells at 100 °C.
• Testing of Zn//Te full batteries at 100 °C.

Main Results:

• Identified spontaneous Zn corrosion and hydrogen evolution as key limitations at high temperatures.
• The developed electrolyte suppressed water reactivity by strengthening O-H bonds and reducing water in the Zn2+ solvation sheath.
• Achieved reversible Zn deposition with 98.1% Coulombic efficiency and over 500 cycles for Zn//Zn batteries at 100 °C.
• Demonstrated stable cycling of Zn//Te full batteries at 100 °C.

Conclusions:

• The crowding agent effectively enhances the stability of aqueous electrolytes at high temperatures.
• The modified aqueous electrolyte enables robust and long-lasting performance of ZMBs at 100 °C.
• This work paves the way for safe and reliable high-temperature energy storage solutions using ZMBs.