Fiber-shaped energy storage devices are indispensable parts of wearable and portable electronics. Aqueous rechargeable Ni/Fe battery is a very appropriate energy storage device due to their good safety without organic electrolytes, high ionic conductivity, and low cost. Unfortunately, the low energy density, poor power density and cycling performance hinder its further practical applications. In this study, in order to obtain high performance negative iron-based material, we first synthesized α-iron oxide (α-Fe₂O₃) nanorods (NRs) with superstructures on the surface of highly conductive carbon nanotube fibers (CNTFs), then electrically conductive polypyrrole (PPy) was coated to enhance the electron, ion diffusion and cycle stability. The as-prepared α-Fe₂O₃@PPy NRs/CNTF electrode shows a high specific capacity of 0.62 Ah cm^-3 at the current density of 1 A cm^-3. Furthermore, the Ni/Fe battery that was assembled by the above negative electrode shows a maximum volumetric energy density of 15.47 mWh cm^-3 with 228.2 mW cm^-3 at a current density of 1 A cm^-3. The cycling durability and mechanical flexibility of the Ni/Fe battery were tested, which show good prospect for practical application. In summary, these merits make it possible for our Ni/Fe battery to have practical applications in next generation flexible energy storage devices.

纤维状储能装置是可穿戴和便携式电子产品不可或缺的组成部分。水系可充电镍铁电池具有安全性好、无需有机电解质、离子电导率高、成本低等优点，是一种非常合适的储能装置。不幸的是，低能量密度、差的功率密度和循环性能阻碍了其进一步的实际应用。在这项研究中，为了获得高性能的负极铁基材料，我们首先在高导电碳纳米管纤维（CNTFs）的表面合成了具有超结构的α-氧化铁（α-Fe ₂ O ₃ ）纳米棒（NRs），然后涂覆导电聚吡咯（PPy）以增强电子、离子扩散和循环稳定性。所制备的α-Fe ₂ O₃ @PPy NRs/CNTF电极在1 A cm ^-3的电流密度下表现出0.62 Ah cm ^-3的高比容量。此外，由上述负极组装的Ni/Fe电池在1A cm -3 电流密度下的最大体积能量密度为15.47 mWh cm ^-3和^228.2 mW cm ^-3。测试了Ni/Fe电池的循环耐久性和机械柔韧性，显示出良好的实际应用前景。总之，这些优点使我们的镍铁电池有可能在下一代柔性储能设备中得到实际应用。