Wood-Structured Electrolyte for Ultra-Stable Zinc-Ion Batteries Under High Discharge Conditions

Area of Science:

• Materials Science
• Electrochemistry
• Energy Storage

Background:

• Aqueous zinc-ion batteries (AZIBs) show promise but are limited by performance issues at high depths of discharge (DOD).
• Challenges include imbalanced zinc ion transport, hydrogen evolution, and uneven plating/stripping.
• Existing electrolytes struggle to maintain stability beyond 70% DOD.

Purpose of the Study:

• To develop a novel electrolyte for AZIBs that enables stable operation at high DOD.
• To address the limitations of Zn2+ transport imbalance and electrode degradation.
• To establish a new design strategy for high-performance AZIB electrolytes.

Main Methods:

• Fabrication of a radial wood-based hierarchical heterogeneous interconnected structure (HHIS) electrolyte.
• Characterization of Zn2+ transport pathways within the HHIS structure.
• Electrochemical cycling tests of AZIBs with the HHIS electrolyte under high current and high DOD.

Main Results:

• The HHIS electrolyte facilitates uniform Zn2+ deposition via coordinated migration along wood's natural structures.
• Stable cycling exceeding 9000 hours was achieved at low DOD and over 3300 hours at 83.1% DOD.
• The HHIS electrolyte effectively stabilized the zinc anode under high current densities.

Conclusions:

• Wood can be directly converted into a high-performance electrolyte for AZIBs.
• The HHIS design strategy successfully mitigates high-DOD instability in AZIBs.
• This approach offers a pathway for the commercialization of advanced AZIB electrolytes.