Electrical-Conductive/Insulating Bi-Functional Layers for Stable Zn Metal Anode

Area of Science:

• Electrochemistry
• Materials Science
• Energy Storage

Background:

• Zinc-ion batteries (ZIBs) offer a cost-effective and safe solution for large-scale energy storage.
• Challenges in ZIBs include zinc anode dendrite growth and side reactions, leading to low coulombic efficiency (CE) and poor cycling stability.
• Addressing these issues is crucial for realizing the practical application of ZIBs.

Purpose of the Study:

• To develop a stable zinc metal anode for enhanced ZIB performance.
• To investigate the efficacy of a conductive/insulating bi-functional coating layer (CIBL) in mitigating anode degradation.
• To demonstrate the long-term cycling stability and high CE of ZIBs utilizing the CIBL-modified anode.

Main Methods:

• Fabrication of a CIBL comprising porous silver (Ag) nanowires (NWs) as the conductive layer and polyimide (PI) as the insulating layer.
• Coating the CIBL onto zinc metal anodes to create CIBL-Zn.
• Electrochemical testing of CIBL-Zn//CIBL-Zn symmetric cells and CIBL-Zn//V2O5 full cells.

Main Results:

• The CIBL effectively reduces the nucleation barrier for zinc deposition and confines Zn2+ ions, promoting uniform plating.
• CIBL-Zn//CIBL-Zn symmetric cells demonstrated stable plating/stripping for over 1300 hours at 1 mA cm-2 with a CE of 99.2% after 1000 cycles.
• CIBL-Zn//V2O5 full cells exhibited a capacity of 289.2 mAh g-1 at 5 A g-1 after 3000 cycles with no capacity degradation.

Conclusions:

• The CIBL strategy successfully suppresses dendrite growth and side reactions in zinc anodes.
• The bi-functional coating significantly improves the coulombic efficiency and cycling stability of zinc metal anodes.
• The CIBL shows great promise for practical applications in high-performance and long-lasting zinc-ion batteries.