Related Experiment Video
Updated: Jun 20, 2026
A Protocol for Electrochemical Evaluations and State of Charge Diagnostics of a Symmetric Organic Redox Flow Battery
Published on: February 13, 2017
Electronically Modulated TpPa COF as a High-Performance Iodine Host for Zn-I2 Batteries
Yunlong Sun1, Qiwang Shao1, Shuangshou Wang2
1School of Materials Science and Engineering, Anhui Province Key Laboratory of Efficient Conversion and Solid-State Storage of Hydrogen & Electricity, Anhui University of Technology, Ma'anshan, Anhui, 243032, China.
Engineered covalent organic frameworks (COFs) improve zinc-iodine battery performance by enhancing iodine utilization and stability. Nitro-functionalized COFs demonstrate remarkable capacity retention and stable operation under challenging conditions.
Area of Science:
- Materials Science
- Electrochemistry
- Energy Storage
Background:
- Aqueous zinc-iodine (Zn-I2) batteries face challenges with poor iodine utilization and limited cycling stability due to polyiodide shuttle effects.
- Covalent organic frameworks (COFs) offer potential as cathode hosts but require structural and electronic optimization.
Purpose of the Study:
- To enhance iodine utilization and cycling stability in Zn-I2 batteries through side-group engineering of hexagonal porous TpPa COFs.
- To investigate the impact of electronic modulation on COF properties and their interaction with polyiodide species.
Main Methods:
- Synthesis and characterization of nitro-functionalized TpPa COF (TpPa-NO2).
- Electrochemical testing of Zn-I2 batteries utilizing TpPa-NO2 as cathode host.
- Theoretical simulations (DFT) to understand electronic structure and polyiodide affinity.
- In situ Raman and UV-vis spectroscopy to probe reaction mechanisms and polyiodide behavior.
Main Results:
- TpPa-NO2 exhibited a high specific capacity (≈183 mAh g−1 at 0.1 A g−1) and excellent cycling stability (84.3% retention after 10,000 cycles at 5 A g−1).
- Batteries demonstrated stable operation at low temperatures (-5 °C) and high iodine loading (≈15 mg cm−2) with mitigated polarization.
- Electronic modulation in TpPa-NO2 reduced the band gap and increased polyiodide affinity, improving iodine utilization.
- Spectroscopic studies confirmed a dominant I−/I5− redox pathway and suppressed polyiodide dissolution.
Conclusions:
- Electronically tailored COFs, specifically TpPa-NO2, are promising cathode hosts for high-performance Zn-I2 batteries.
- Side-group engineering provides an effective dual strategy to enhance iodine utilization and mitigate the shuttle effect in Zn-I2 batteries.
- This approach offers a pathway towards developing long-life and stable aqueous metal-iodine batteries.
