In Situ Constructing Robust Solid-Electrolyte Interphase for Advanced Zn Anode in Acidic Electrolyte

Area of Science:

• Electrochemistry
• Materials Science
• Energy Storage

Background:

• Acidic electrolytes (pH<4) inhibit Zn anode dendrites but cause hydrogen evolution and corrosion.
• Developing a protective solid-electrolyte interphase (SEI) is crucial for acidic aqueous Zn-ion batteries (AZIBs).

Purpose of the Study:

• To construct a robust organic/inorganic layered SEI on the Zn anode for acidic AZIBs.
• To improve the stability and performance of AZIBs by addressing interface issues.

Main Methods:

• In situ construction of SEI via tetraethylammonium tetrafluoroborate (TEATFB) decomposition.
• Utilizing BF4--triggered hydrolysis chemistry for SEI formation.
• Characterization of SEI structure and electrochemical performance.

Main Results:

• The SEI features an inner ZnF2 layer for Zn2+ migration and an outer organic layer for volume accommodation.
• Preferential adsorption of TEA+ cations forms a hydrophobic EDL, inducing uniform Zn deposition and water exclusion.
• Achieved 99.9% average Coulombic efficiency (ACE) in Zn||Cu cells and 3000 h cycle life in Zn||Zn cells.
• Zn||MnO2 full cells demonstrated 82% capacity retention after 500 cycles.

Conclusions:

• The constructed SEI effectively protects the Zn anode in acidic electrolytes.
• The SEI promotes uniform Zn deposition and enhances ion transport, leading to superior battery performance.
• This strategy offers a promising pathway for developing high-performance acidic AZIBs.