Identification and characterization of novel battery electrode materials are key factors in transitioning the grids to renewable energy provision. Given the scale of the challenge, special attention should be paid to safety and availability of resources. This paper presents a new electrode material for aqueous batteries and supercapacitors based on highly available resources: chromium(II) hexacyanoferrate (CrHCF) thin films. Electrodeposited CrHCF exhibited “half-charge” potentials (E1/2) of ∼0.69 and ∼0.72 V versus silver/silver chloride (reference electrode) for Na and K intercalation, respectively, a high specific capacity of ∼88 mA h/g (10 C), and a good rate performance at fast C-rate (360 C). The electrolyte composition significantly influences the long-term cycling stability of the CrHCF electrodes and the choice of the intercalating alkali metal cations significantly impacts the E1/2 potentials. Finally, a CrHCF-based symmetric cell (quasi-supercapacitor) was constructed and showed high specific energy of ∼4.6 W h/kg at 100 C.
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机译：新型电池电极材料的鉴定和表征是将电网过渡到可再生能源供应的关键因素。考虑到挑战的规模，应特别注意资源的安全性和可用性。本文基于高度可用的资源，提出了一种用于水性电池和超级电容器的新型电极材料：六氰合铁酸铬（II）薄膜。相对于银/氯化银（参比电极），电沉积CrHCF的“半电荷”电势（E1 / 2）分别为〜0.69 V和〜0.72 V，相对于银/氯化银（参比电极）而言，其高比容量为〜88 mA h / g（ 10 C），以及在快速C速率（360 C）时的良好速率性能。电解质成分会严重影响CrHCF电极的长期循环稳定性，而插层式碱金属阳离子的选择会严重影响E1 / 2电位。最后，构建了基于CrHCF的对称电池（准超级电容器），并在100 C时显示出约4.6 W h / kg的高比能。
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