# Chinese team's zinc-iodine cell keeps 89.34% capacity after 10,000 cycles in lab tests

- Published: 2026-11-05 05:27 UTC
- Section: Power & Energy › Batteries
- Tags: zinc-ion battery, zinc-iodine battery, iodine shuttle effect, carbon nanotube cathode, aqueous energy storage, battery cycle life, hydroxyl functionalization, pouch cell prototype, Science China Chemistry
- URL: https://realtech.media/news/rt-ef54e495035298689b0e3023_chinese_team_s/

**Jilin University and Changchun Institute of Applied Chemistry modified a carbon nanotube cathode to curb iodine shuttling in an aqueous zinc battery; a pouch-cell prototype was also built.**

![Chinese team's zinc-iodine cell keeps 89.34% capacity after 10,000 cycles in lab tests](https://sgzwpqqelzmajkcubgkl.supabase.co/storage/v1/object/public/rt-media/2026/11/ef3bbdfc5bf0a687.webp)
*Interesting Engineering*

Researchers from Jilin University and the Changchun Institute of Applied Chemistry in China have developed an aqueous zinc-iodine battery that retained 89.34 percent of its original capacity after more than 10,000 charge-discharge cycles, Interesting Engineering reports. According to the team, this corresponds to more than 3,500 hours of continuous operation. [1] The results were published in Science China Chemistry.

## Why iodine cathodes degrade

Aqueous zinc-ion batteries typically use iodine-based cathodes, which offer long cycling stability, fast charge and discharge, and potential for high energy storage. [1] However, such cathodes conduct electricity poorly, change structure during cycling and allow iodine ions to migrate through the cell. This shuttle effect lowers efficiency, speeds up material degradation and shortens battery life. [1]

To address this, the team modified the functional group chemistry of the cathode and made self-supporting carbon nanotube cathodes (SSCC). They compared the iodine adsorption of nanotubes functionalized with hydroxyl (‒OH), carboxyl (‒COOH) and amine (‒NH₂) groups with that of unmodified ones. Spectroscopy and microscopy confirmed that the groups were introduced and that iodine was loaded uniformly. According to the authors, the hydroxyl-modified nanotubes held iodine ions in place, which reduced energy loss. [1]

## Test results and pouch-cell prototype

In laboratory tests, the cathode delivered an initial reversible capacity of 175.5 mAh/g at a current density of 1 A/g. After more than 10,000 cycles it retained 89.34 percent of its original capacity. At 10 A/g, the capacity was 120 mAh/g, with a cycling life of 93,400 cycles. [1]

In situ Raman spectroscopy during operation and ex situ X-ray photoelectron spectroscopy after cycling showed that the iodine species were converted repeatedly and reversibly. The researchers report that the modified cathode eliminated the iodine shuttle effect, so iodine ions did not remain in the electrolyte. [1]

The team also built a larger pouch-cell prototype containing 150 mg of iodine. It operated at 1.1 V, delivered an actual capacity of 23.8 mAh and retained 91.7 percent of its original capacity after 350 cycles. [1] The authors conclude that changing the functional groups of the cathode is a simple way to improve iodine conversion kinetics and stabilize aqueous zinc-iodine batteries based on zinc metal. [1]

## Sources

1. [Interesting Engineering](https://interestingengineering.com/energy/zinc-ion-batteries-retain-capacity)

---

Source: RealTech, realtech.media — https://realtech.media/news/rt-ef54e495035298689b0e3023_chinese_team_s/