为了探究作为锌离子电池正极的Na_1.25V₃O₈的电化学性能是否还具有进一步提升的空间，文中通过水热-固相法成功合成了纯Na_1.25V₃O₈和铷掺杂Na_1.25Rb _x V₃O₈纳米棒。根据XRD谱图可以看出，随着铷含量的增加衍射峰向低角度偏移且没有新的衍射峰生成，表明Na_1.25Rb _x V₃O₈样品为纯相且保持空间群为P21/m的结构对称性。这一结果说明铷离子成功进入了Na_1.25Rb _x V₃O₈层状化合物的层间。SEM和TEM形貌分析结果显示，随着Rb⁺掺杂量的增加，纳米棒的形貌变得更大、更厚，会降低材料的比表面积，导致阻抗的增加和Zn²⁺离子扩散系数的降低，对电化学性能产生不利的影响。EIS和GITT测试结果也证实，Rb⁺的掺入会使其比容量降低。电化学测试结果显示，虽然未掺杂的Na_1.25V₃O₈纳米棒表现出370 mA·h/g的初始比容量，但随着充放电过程的进行其比容量衰减很快，在电流密度为100 mA/g条件下长循环100圈后的放电比容量衰减了初始容量的50%；而Rb⁺掺杂的纳米棒尽管比容量有所降低，但其循环稳定性和倍率性能均得到显著提升。其中Rb掺杂量为1%的样品初始比容量为336 mA·h/g，在相同条件下循环100圈后和初始比容量相比只衰减了6%；当Rb掺杂量增加到5%时，尽管初始比容量只有217 mA·h/g，但100圈后放电比容量和初始比容量相比几乎没有衰减。利用XPS能谱和原位XRD技术对其锌离子存储机理进行了深入分析，该水系锌离子电池体系中Na_1.25Rb _x V₃O₈正极材料的氧化还原反应机理主要以化学转化反应为主，其中只有充电反应过程是可逆的。

In order to know whether there is space for the improvement of the electrochemical performance of Na_1.25V₃O₈ as cathode for zinc-ion batteries, this study successfully synthesized pure Na_1.25V₃O₈ and Rb⁺ ion doped Na_1.25V₃O₈ nanorods through hydrothermal method and solid phase method. With the help of XRD patterns, the diffraction peak shifts to a low angle and no new diffraction peak is generated with the increase of rubidium content, indicating that the Na_1.25Rb _x V₃O₈ sample is pure phase and maintain the structural symmetry of P21/m space group. This result indicate that rubidium ions have successfully entered the interlayer of Na_1.25Rb _x V₃O₈ layered compound. The results of SEM images and TEM images analysis show that, with the insertion of Rb⁺, scale of Na_1.25V₃O₈ nanorods become thicker and larger, which would reduce the specific surface and lead to the increase of impedance and reducing the ion diffusion coefficients, resulting in poor electrochemical performance. EIS and GITT results further confirm that the insertion of Rb⁺ will lead to the decrease in capacity. Electrochemical testing results show that bare Na_1.25V₃O₈ nanorods exhibit about 370 mA·h/g initial capacity, but it decreases fast with the increasing times of charge and discharge circle. After 100 cycles of discharge and charge processes at current density of 100 mA/g, discharge capacity decays about 50% compared to initial capacity. Although the specific capacity of Rb+-doped nanorods is reduced, their cycle stability and rate performance are significantly improved. When the amount of doped Rb is 1%, the initial capacity is 336 mA·h/g, but after 100 cycles of discharge and charge processes under the same conditions, the discharge capacity only decays about 6% compared to initial discharge capacity. When the amount of Rb increases to 5%, the initial capacity is merely 217 mA·h/g, but no capacity lost compared to initial capacity. The mechanism of zinc ion storage was analyzed through in-situ XRD and ex-situ XPS. The redox reaction mechanism of Na_1.25Rb _x V₃O₈ cathode material in the ZIBs is mainly based on chemical conversion reaction, in which only the charging reaction process is reversible.