High-voltage and dendrite-free zinc-iodine flow battery.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 39043688.
- Also identified by DOI 10.1038/s41467-024-50543-2 and PMC identifier 11266666.
- Licence recorded as CC BY.
- The licence permits redistribution, so the abstract is shown in full and the full text is available from the publisher.
Abstract
Zn-I<sub>2</sub> flow batteries, with a standard voltage of 1.29 V based on the redox potential gap between the Zn<sup>2+</sup>-negolyte (-0.76 vs. SHE) and I<sub>2</sub>-posolyte (0.53 vs. SHE), are gaining attention for their safety, sustainability, and environmental-friendliness. However, the significant growth of Zn dendrites and the formation of dead Zn generally prevent them from being cycled at high current density (>80 mA cm<sup>-2</sup>). In addition, the crossover of Zn<sup>2+</sup> across cation-exchange-membrane also limits their cycle stability. Herein, we propose a chelated Zn(P<sub>2</sub>O<sub>7</sub>)<sub>2</sub><sup>6-</sup> (donated as Zn(PPi)<sub>2</sub><sup>6-</sup>) negolyte, which facilitates dendrite-free Zn plating and effectively prevents Zn<sup>2+</sup> crossover. Remarkably, the utilization of chelated Zn(PPi)<sub>2</sub><sup>6-</sup> as a negolyte shifts the Zn<sup>2+</sup>/Zn plating/stripping potential to -1.08 V (vs. SHE), increasing cell voltage to 1.61 V. Such high voltage Zn-I<sub>2</sub> flow battery shows a promising stability over 250 cycles at a high current density of 200 mA cm<sup>-2</sup>, and a high power density up to 606.5 mW cm<sup>-2</sup>.