Abstract Fiber-shaped asymmetric supercapacitors (FASCs) have emerged as intriguing energy storage devices for next-generation wearable electronics. However, the limited specific capacitances that arise from electrode materials severely restrict further enhancement of their energy densities. We successfully fabricated a hierarchically structured three-dimensional VO2@polypyrrole (VO2@PPy) core-shell nanowire array (NWA) on carbon nanotube fiber (CNTF) via a facile and cost-effective route. Such a composite structure not only enables a highly pseudo-capacitive VO2 core to provide a large surface area for reversible Faradic redox reactions, but also uses a highly conductive PPy shell to suppress the dissolution of VO2, thus making the hybrid fiber a new state of fibrous electrode with exceptional specific capacitance and rate behavior. To benefit from these superior features, we assembled a high-performance FASC with an operating voltage of 1.8 V and achieved a remarkable specific capacitance of 60.6 F/cm3 and an extraordinary energy density up to 29.3 mWh/cm3 at a current density of 0.25 A/cm3. In addition, the FASC device exhibited excellent flexibility; its capacitance retention remained at 88.9% after bending 4000 times. Thus, these findings should help to develop advanced VO2-based cathodes for next-generation wearable energy storage devices.

中文翻译：

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在碳纳米管纤维上生长的分层结构的 VO 2 @PPy 核壳纳米线阵列作为高性能可穿戴非对称超级电容器的先进阴极

摘要 纤维状非对称超级电容器 (FASC) 已成为下一代可穿戴电子产品的有趣储能设备。然而，电极材料产生的有限比电容严重限制了其能量密度的进一步提高。我们通过简便且具有成本效益的途径在碳纳米管纤维（CNTF）上成功制造了分层结构的三维 VO2@聚吡咯（VO2@PPy）核壳纳米线阵列（NWA）。这种复合结构不仅使高赝电容的 VO2 核为可逆法拉第氧化还原反应提供大表面积，而且使用高导电性 PPy 壳来抑制 VO2 的溶解，从而使混合纤维成为一种新的状态。具有特殊比电容和倍率特性的纤维电极。为了受益于这些卓越的特性，我们组装了一个工作电压为 1.8 V 的高性能 FASC，并在 0.25 A 的电流密度下实现了 60.6 F/cm3 的显着比电容和高达 29.3 mWh/cm3 的非凡能量密度/cm3。此外，FASC 装置表现出优异的柔韧性；弯曲4000次后，其电容保持率仍保持在88.9%。因此，这些发现应该有助于为下一代可穿戴储能设备开发先进的基于 VO2 的阴极。弯曲4000次后，其电容保持率仍保持在88.9%。因此，这些发现应该有助于为下一代可穿戴储能设备开发先进的基于 VO2 的阴极。弯曲4000次后，其电容保持率仍保持在88.9%。因此，这些发现应该有助于为下一代可穿戴储能设备开发先进的基于 VO2 的阴极。