Self-assembled polyelectrolytes with ion-separation accelerating channels for highly stable Zn-ion batteries

Area of Science:

• Electrochemistry
• Materials Science
• Energy Storage

Background:

• Aqueous zinc-ion batteries (AZIBs) are a sustainable energy storage alternative to lithium-ion batteries.
• Challenges in AZIBs include dendrite formation and low Coulombic efficiency due to uncontrolled ion diffusion.
• Uniform zinc nucleation is crucial for stable and efficient battery performance.

Purpose of the Study:

• To develop a strategy for simultaneously regulating cation and anion diffusion in AZIB electrolytes.
• To enhance uniform zinc deposition and improve the cycling stability of zinc anodes.
• To demonstrate the practical viability of the developed anode in large-scale pouch cells.

Main Methods:

• Layer-by-layer self-assembly of poly(allylamine hydrochloride) and poly(acrylic acid) to create dual-ion channels.
• Utilizing electrostatic interactions to separate and guide ion diffusion within the electrolyte.
• Fabricating high mass-loading zinc anodes for Ah-level pouch cells.

Main Results:

• Achieved a Coulombic efficiency (CE) of 99.8% after 1600 cycles in a Cu||Zn cell.
• Demonstrated uniform zinc deposition along the Zn(002) plane.
• A 17.36 Ah pouch cell retained 93.6% capacity after 250 cycles at 1.7 C.

Conclusions:

• The ion-separation accelerating channel effectively regulates ion diffusion, enabling uniform zinc deposition.
• The developed zinc anode exhibits excellent cycling stability and practical viability for large-scale AZIB applications.
• This work paves the way for the commercialization of high-performance aqueous zinc-ion batteries.