A Biomimetic Bidirectional Interphase Enabled by a Single Molecule for Ultra-Stable Zn-I₂ Batteries

Area of Science:

• Electrochemistry
• Materials Science
• Energy Storage

Background:

• Zinc-iodine (Zn-I₂) batteries are promising for grid storage but suffer from zinc dendrites, side reactions, and polyiodide shuttle.
• These issues limit the cycle life and practical application of Zn-I₂ batteries.

Purpose of the Study:

• To introduce sodium camphorsulfonate (SCS) as a biomimetic additive to address key challenges in Zn-I₂ batteries.
• To enhance the stability and cycling performance of Zn-I₂ batteries through a single molecular additive.

Main Methods:

• Incorporation of SCS as an electrolyte additive in Zn-I₂ battery systems.
• Electrochemical characterization including symmetric cell cycling and full cell performance testing.
• Analysis of anode/cathode interfacial behavior and dendrite suppression mechanisms.

Main Results:

• SCS addition suppressed hydrogen evolution reaction (HER) and guided dendrite-free Zn deposition.
• SCS effectively inhibited polyiodide shuttle and mitigated anode corrosion.
• Ultra-stable cycling was achieved: 1449 h in symmetric cells and 26,000 cycles in full cells.
• Pouch cells demonstrated high capacity retention with thick Zn anodes and high iodide loading.

Conclusions:

• SCS acts as a versatile additive, stabilizing both anode and cathode interfaces in Zn-I₂ batteries.
• This cost-effective strategy significantly improves the durability and energy storage capability of Zn-I₂ batteries.
• The findings offer a pathway for developing high-performance and long-lasting Zn-I₂ batteries for grid-scale applications.