Abstract We report the synthesis, physical properties and electrochemical performance of Zn substituted Na 0.44 Mn 1 − x Zn x O 2 ( x = 0 – 0.02) nanostructures as cathode in Na-ion batteries for energy storage applications. These samples stabilize in the orthorhombic structure and the morphology is found to be slab like with 100 – 200 nm width and few micrometer of length. The resistivity measurements show highly insulating nature for all the samples, where the activation energy decreases with increasing Zn concentration indicating more defect levels in the band gap. The cyclic voltammogram (CV) shows reversible oxidation and reduction peaks, which clearly shift towards higher/lower potentials with increasing Zn concentration up to 2%. We observed the specific capacity of about 100 mAh/g at current density of 4 mA/g and improved cycle life for Zn substituted x = 0.005 sample. However, with further increasing the Zn concentration ( x = 0.02 ), the specific capacity decreases, which can be a manifestation of the decreased number of reduction peaks in the CV data.

中文翻译：

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锌取代的 Na0.44Mn1−xZnxO2 纳米结构作为钠离子电池正极的物理性质和电化学性能

摘要 我们报告了 Zn 取代的 Na 0.44 Mn 1 − x Zn x O 2 ( x = 0 – 0.02) 纳米结构作为用于储能应用的钠离子电池阴极的合成、物理性质和电化学性能。这些样品稳定在正交结构中，并且发现形态为板状，宽度为 100 – 200 nm，长度为几微米。电阻率测量显示所有样品的高度绝缘性，其中活化能随着 Zn 浓度的增加而降低，表明带隙中的缺陷水平更多。循环伏安图 (CV) 显示出可逆的氧化和还原峰，随着 Zn 浓度增加至 2%，这些峰明显向更高/更低的电位移动。我们在 4 mA/g 的电流密度下观察到约 100 mAh/g 的比容量，并改善了锌取代 x = 0.005 样品的循环寿命。然而，随着 Zn 浓度的进一步增加（ x = 0.02 ），比容量降低，这可能是 CV 数据中还原峰数量减少的表现。