フロー電池向けに高可逆な4電子移動を実現するスズ系負極を開発（Researchers Develop Tin-Based Anode Enabling Highly Reversible Four-Electron Transfer for Flow Batteries）

2026-10-10 中国科学院（CAS）

＜関連情報＞

• https://english.cas.cn/newsroom/research-news/202610/t20261010_1202173.shtml
• https://www.nature.com/articles/s41557-026-02275-7

高エネルギー密度フロー電池用可逆性Sn4 + /Sn0アノード Reversible Sn4+/Sn0 anode for high-energy-density flow batteries

Yue Ao, Xiaoxiao Wang, Chengji Zhao, Yanyan Zhang, Zhangquan Peng, Fuyi Wang, Shengli Chen, Congxin Xie & Xianfeng Li
Nature Chemistry  Published:09 October 2026
DOI:https://doi.org/10.1038/s41557-026-02275-7

Abstract

Aqueous batteries offer a relatively safe, energy-dense means to store electrochemical energy. Tin is a promising anode material, due to its potential four-electron redox-active states and lack of dendrite formation. However, the irreversible electrochemical behaviour of the Sn⁴⁺/Sn²⁺ couple have limited high-capacity anode development. Here we achieve the reversible Sn⁴⁺/Sn²⁺ conversion, enabling a Sn⁴⁺/Sn⁰ anode for high-energy-density flow batteries. We accomplish this by adding iodide to highly soluble SnCl₄ solutions at ratios that form SnCl₆²⁻ and SnI₆²⁻ intermediate complexes. SnI₆²⁻ reduces reorganization energy during the electrochemical reaction of Sn⁴⁺/Sn²⁺, ensuring reversibility. SnCl₆²⁻ imparts anolyte solubility. The redox peak potential difference decreased from 978 mV (Cl⁻) to 97 mV (I⁻), with a substantial decrease to the electron transfer impedance decrease. Coupled with Br⁻/Br₂, the assembled full battery showed 89% energy efficiency at 40 mA cm⁻², 227 Ah l⁻¹ anolyte capacity and 205 Wh l⁻¹ anolyte energy density. Based on these studies, we developed a kilowatt-scale stack that can operate stably for over 1,000 h.