As our reliance on renewable energy sources grows, so too does our need to store this energy to mitigate against troughs in supply. Energy storage in batteries or by conversion to chemical fuels are the two most flexible and scalable options, but are normally considered mutually exclusive. Energy storage solutions that can act as both batteries and fuel generation devices (depending on the requirements of the user) could therefore revolutionize the uptake and use of renewably generated energy. Here, we present a polyoxoanion, [P₂W₁₈O₆₂]⁶⁻, that can be reversibly reduced and protonated by 18 electrons/H⁺ per anion in aqueous solution, and that can act either as a high-performance redox flow battery electrolyte (giving a practical discharged energy density of 225 Wh l⁻¹ with a theoretical energy density of more than 1,000 Wh l⁻¹), or as a mediator in an electrolytic cell for the on-demand generation of hydrogen.

随着我们对可再生能源的依赖增加，我们也需要存储这种能源以缓解供应低谷的需求。电池中的能量存储或通过转换为化学燃料的能量存储是两个最灵活和可扩展的选项，但通常被认为是互斥的。因此，既可以用作电池又可以用作燃料产生装置的储能解决方案（取决于用户的要求）可以彻底改变可再生能源的吸收和使用。在这里，我们提出了一种聚氧阴离子[P ₂ W ₁₈ O ₆₂ ] ⁶⁻，它可以通过18个电子/ H ⁺可逆地还原和质子化水溶液中的阴离子，它既可以用作高性能氧化还原液流电池电解质（实际放电能量密度为225 Wh l ^-1，理论能量密度大于1,000 Wh l ^-1），也可以用作电解池中的介体，用于按需产生氢气。