Organic dual-ion batteries show high energy densities which are, in principle, suitable for large-scale energy storage, but they suffer from inherent instability and safety issues. Aqueous batteries feature low cost, high ionic conductivity, and much improved safety, showing more enormous potential for grid-scale energy storage. Conventional dual-ion batteries (DIBs) involve the reversible intercalation of electrolyte-born anions and cations into cathodes and anodes, respectively. Here we develop a new full aqueous battery involving the co-intercalation of K⁺ and H⁺ in both anode and cathode. This dual-ion battery constitutes a cathode of defective Prussian Blue nanostructures, an anode of atomically thin Ti₃C₂T_x MXene nanosheets, and an aqueous electrolyte of mildly acidic KNO₃ solution. The open frameworks of both cathode and anode together with the existence of abundant structural water in both electrodes enable fast kinetics for K⁺ and H⁺ (de)intercalation. Accordingly, the full battery exhibits improved energy (e.g., 41.5 Wh kg¹ based on both cathode and anode) and power (e.g., 5030 W kg¹) densities, whereas capacity retention of 74% can be achieved after 3000 cycles. We believe that this new dual-cation battery design presents a promising way to improve aqueous battery performance.

有机双离子电池显示出高能量密度，原则上适合于大规模储能，但它们固有的不稳定和安全性问题。水性电池具有低成本，高离子电导率和安全性大大提高的特点，显示出更大的电网规模储能潜力。常规的双离子电池（DIB）分别将可生电解质的阴离子和阳离子可逆地插入阴极和阳极中。在这里，我们开发了一种新的全水电池，涉及在阳极和阴极中共嵌入K ⁺和H ⁺。这种双离子电池构成了具有缺陷的普鲁士蓝纳米结构的阴极，是原子级薄的Ti ₃ C ₂ T _x的阳极MXene纳米片和中等酸性KNO ₃水溶液。阴极和阳极的开放框架以及两个电极中均存在大量结构水，可实现K ⁺和H ⁺（脱）嵌入的快速动力学。因此，整个电池展现出改进的能量密度（例如，基于阴极和阳极两者为41.5 Wh kg ¹）和功率（例如5030 W kg ¹）的密度，而在3000次循环之后可以实现74％的容量保持率。我们相信，这种新的双阳离子电池设计提出了一种改善水性电池性能的有前途的方法。