Rechargeable hydrogen gas batteries are attracting great interest for emerging large-scale energy storage owing to their fast charge/discharge rates and excellent stability. Despite recent progress in the development of different hydrogen gas batteries, it is highly desirable to explore new cathodes for flourishing the hydrogen gas battery chemistries. Different from the previous hydrogen gas battery systems with solid or semi-solid cathode reactions, in this study, we propose and demonstrate an iron–hydrogen gas battery in a liquid cathode with low-cost [Fe(CN)₆]^3–/[Fe(CN)₆]^4– redox couple by pairing with the hydrogen gas anode. The designed iron–hydrogen gas battery exhibits a high energy efficiency of 93% with a discharge plateau of ~1.29 V at a current of 10 mA, an energy efficiency of 73% even at a high current of 60 mA and an ultra-stable cycling life of over 20000 cycles. This article highlights the significance of the deployment of liquid redox molecules as active species in hydrogen gas batteries, which provides an effective strategy to broaden the hydrogen gas battery systems for large-scale energy storage applications.

可充电氢气电池由于其快速的充电/放电速率和出色的稳定性而引起了新兴的大规模能量存储的极大兴趣。尽管最近在开发不同的氢气电池方面取得了进展，但是非常需要探索用于使氢气电池化学蓬勃发展的新阴极。与先前的具有固态或半固态阴极反应的氢气电池系统不同，在本研究中，我们提出并演示了具有低成本[Fe（CN）₆ ] ^3– / [的液态阴极中的铁氢气体电池Fe（CN）₆ ] ^4–氧化还原与氢气阳极配对。设计的铁氢气体电池在10 mA的电流下具有93％的高能量效率，在约1.29 V的放电平稳性，即使在60 mA的高电流下也具有73％的能量效率，并且具有超稳定的循环寿命超过20000个周期。本文强调了将液态氧化还原分子作为活性物质部署在氢气电池中的重要性，这为扩大氢气电池系统用于大规模能量存储应用提供了有效的策略。