Constructing Dynamic Cross-Linking Networks as Durable Bifunctional Coating for Highly Stable Zinc Anodes

Area of Science:

• Materials Science
• Electrochemistry
• Energy Storage

Background:

• Aqueous zinc-ion batteries (AZIBs) face challenges from zinc dendrite growth and water-induced side reactions, limiting their commercial viability.
• These issues cause rapid capacity fading and poor cycling stability in zinc anodes.
• Developing protective strategies for zinc anodes is crucial for advancing AZIB technology.

Purpose of the Study:

• To develop a novel bifunctional network coating for zinc anodes to enhance the stability and performance of AZIBs.
• To investigate the protective mechanisms of the coating against dendrite formation and side reactions.
• To evaluate the long-term cycling performance and durability of the modified zinc anode.

Main Methods:

• A bifunctional network coating of dynamically cross-linking sodium alginate with trehalose (AT) was constructed on the zinc anode (Zn@AT).
• The AT coating's ability to induce uniform Zn2+ ion flux and inhibit water activity was analyzed.
• The self-healing capacity of the AT coating during battery cycling was assessed.
• Symmetric cells and full cells (Zn@AT//MnO2) were assembled to evaluate electrochemical performance.

Main Results:

• The AT coating effectively induced uniform Zn2+ ion flux and suppressed water-induced side reactions.
• The Zn@AT anode exhibited remarkable cycling stability, lasting 2787 hours at 2 mA cm-2/2 mAh cm-2 and 1087 hours at 10 mA cm-2/10 mAh cm-2.
• The Zn@AT//MnO2 full cell demonstrated a high specific capacity of 175 mAh g-1 after 400 cycles.
• The dynamic cross-linking provided the AT coating with self-healing capabilities.

Conclusions:

• The rationally designed AT coating provides an effective strategy to enhance the durability and cycling performance of zinc anodes in AZIBs.
• The bifunctional nature of the coating, offering uniform ion flux and water suppression, is key to its success.
• This work paves the way for the development of practical and long-lasting aqueous zinc-ion batteries.