Reprogramming Ion-Transport Dimensionality via Crystal-Channel Engineering to Stabilize Zinc Anodes

Area of Science:

• Materials Science
• Electrochemistry
• Energy Storage

Background:

• Unstable zinc (Zn) deposition in aqueous zinc-ion batteries is a major challenge, driven by 2D interfacial Zn²⁺ transport that leads to dendrite formation.
• Current strategies struggle to overcome the limitations of lateral ion diffusion, hindering battery longevity and safety.

Purpose of the Study:

• To fundamentally regulate zinc deposition by reprogramming the dimensionality of ion transport.
• To develop a novel electrolyte system for stable and uniform zinc plating in batteries.

Main Methods:

• Incorporation of a 3D interpenetrated covalent organic framework (COF) with crown-ether moieties into a hydrogel electrolyte.
• Selective coordination of Zn²⁺ by macrocyclic sites within the COF, displacing water molecules.
• Facilitation of isotropic bulk ion migration through interconnected crystalline channels.

Main Results:

• The engineered electrolyte converted Zn²⁺ transport from interface-limited diffusion to bulk-governed 3D flux, ensuring uniform Zn deposition.
• Symmetric Zn cells demonstrated stable cycling for over 2000 hours at 1 mA cm⁻².
• Zn||NH₄V₄O₁₀ full cells retained 81.6% capacity after 3000 cycles.

Conclusions:

• Ion-transport dimensionality is a critical factor for metal-deposition stability in batteries.
• The developed COF-based hydrogel electrolyte offers a general strategy for enhancing zinc-ion battery performance.
• This approach provides a pathway for designing advanced electrolytes for next-generation energy storage.