Abstract Dual ion batteries (DIBs) that involve the intercalation/de-intercalation behavior of cations and anions present considerable application prospect in large-scale energy storage applications. However, the large size of anions has restricted the reversible intercalation in the cathode of DIBs efficiently. Here we propose N,N,N’,N’- tetraphenyl-1,1’-biphenyl-4,4’-diamine (TPB) with large π-electron conjugate system and amino redox groups as the cathode material of DIBs for the first time. TPB displays the reversible capacity of 77.4 and 52 mAh g-1 at the current densities of 50 and 1000 mA g-1 respectively, and the capacity retention of 61% after 450 cycles at 50 mA g-1. The PF6- storage mechanism of TPB has been studied by molecular structure evolution, quantitative kinetics and theoretical calculations, which indicate TPB presents the redox activity to form/break the C=N+ bond for storing PF6- around the N atoms and the C atoms of biphenyl groups reversibly. This work provides insight into designing and understanding the high anion storage cathodes of DIBs.

中文翻译：

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四苯基联苯二胺：深入了解作为双离子电池阴极的阴离子存储机制

摘要 涉及阳离子和阴离子嵌入/脱嵌行为的双离子电池（DIBs）在大规模储能应用中具有可观的应用前景。然而，大尺寸的阴离子有效地限制了DIBs阴极的可逆嵌入。在这里，我们提出了具有大 π 电子共轭体系和氨基氧化还原基团的 N,N,N',N'-四苯基-1,1'-联苯-4,4'-二胺 (TPB) 作为 DIB 的阴极材料，用于第一次。TPB 在电流密度为 50 和 1000 mA g-1 时的可逆容量分别为 77.4 和 52 mAh g-1，在 50 mA g-1 下循环 450 次后容量保持率为 61%。通过分子结构演化、定量动力学和理论计算研究了TPB的PF6-储存机制，这表明 TPB 具有氧化还原活性，可以形成/破坏 C=N+ 键，从而可逆地将 PF6- 储存在 N 原子和联苯基的 C 原子周围。这项工作为设计和理解 DIB 的高阴离子存储阴极提供了见解。