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Structural Disorder-Order Transition Driven by Valence Variation: Iodine Trapping via a Chemo-Physical Synergistic
Lizhi Zhu1, Yunhuai Zhang1, Kai Li1
1Department of Applied Chemistry, College of Chemistry and Chemical Engineering, Chongqing University, Chongqing, P. R. China.
Small (Weinheim an Der Bergstrasse, Germany)
|July 6, 2026
Summary
This study introduces a novel strategy using a porous CuVO compound to immobilize iodine in sodium-iodine (Na-I2) batteries, preventing dissolution and shuttle effects for improved performance.
Area of Science:
- Materials Science
- Electrochemistry
- Energy Storage
Background:
- Iodine dissolution and shuttle effect in Na-I2 batteries limit performance.
- Effective iodine immobilization is crucial for stable battery operation.
Purpose of the Study:
- To develop a chemo-physical synergistic strategy for iodine immobilization in Na-I2 batteries.
- To investigate the electrochemical performance of the immobilized iodine system.
Main Methods:
- Synthesis of a 3D porous Cu3(OH)2V2O7·2H2O (CuVO) compound.
- Low-temperature annealing and H2O2 treatment to modify the CuVO structure (D-CuVO).
- Electrochemical testing of D-CuVO@I2 in Na-I2 batteries.
Main Results:
- The D-CuVO host effectively immobilizes iodine, preventing dissolution.
- Reversible transformation between D-CuVO and CuI during cycling was observed.
- A new NaVO3 host phase formed during discharge, accommodating iodine.
- The D-CuVO@I2 system demonstrated excellent electrochemical performance.
Conclusions:
- The proposed strategy successfully immobilizes iodine via reversible D-CuVO/CuI transformation and NaVO3 accommodation.
- The D-CuVO@I2 material shows promise for high-performance Na-I2 batteries.
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