Supercapacitors (SCs) are important devices for energy storage because they provide a higher power density as compared to that of batteries. However, SCs with high energy density and good flexibility are still under development. In this study, we fabricated MnO₂-coated Carbon nanotube (CNT)-embedded carbon nanofiber (CNF) (referred to as MnO₂/CNF-CNT) core–shell cables to investigate pseudo-capacitators, while activated CNF-CNTs obtained by CO₂ activation was used for Electrical double-layer capacitors (EDLCs). Owing to the unique structure of the materials and high electrical conductivity of the CNTs on the CNFs, a specific capacitance of 483.5 F/g was achieved using MnO₂/CNF-CNT mat with 1 M Na₂SO₄ aqueous electrolyte at 0.5 A/g. A flexible MnO₂/CNF-CNT supercapacitor was assembled, which was binder-free, electrically conductive media-free, and current collector-free. Further an asymmetric supercapacitor was assembled with the MnO₂/CNF-CNT mat and activated CNF-CNT mat in an ionic liquid (1-ethyl-3-methylimidazolium bis (trifluoromethylsulfonyl) imide) electrolyte. The maximum specific capacitance of, energy density of and power density of 94.25 F/g, 209.4 Wh/kg and 1000 W/kg can be achieved with the asymmetric supercapacitor at 0.5 A/g and 4.0 V. We believe that these materials have significant potential for use in light-weight and flexible SCs.

超级电容器 (SC) 是储能的重要设备，因为与电池相比，它们提供更高的功率密度。然而，具有高能量密度和良好柔韧性的 SCs 仍在开发中。在这项研究中，我们制造了 MnO ₂包覆的碳纳米管（CNT）嵌入的碳纳米纤维（CNF）（称为 MnO ₂ /CNF-CNT）核壳电缆来研究赝电容器，而活化的 CNF-CNTs 通过CO ₂活化用于双电层电容器（EDLC）。由于材料的独特结构和碳纳米管上碳纳米管的高导电性，使用含有 1 M Na ₂ SO 的MnO ₂ /CNF-CNT 垫实现了 483.5 F/g 的比电容₄ 0.5 A/g 的水性电解质。组装了柔性MnO ₂ /CNF-CNT 超级电容器，该电容器不含粘合剂、不含导电介质且不含集电器。此外，在离子液体（1-乙基-3-甲基咪唑鎓双（三氟甲基磺酰基）酰亚胺）电解质中，不对称超级电容器与MnO ₂ /CNF-CNT垫和活化的CNF-CNT垫组装在一起。使用非对称超级电容器在 0.5 A/g 和 4.0 V 时可以实现 94.25 F/g、209.4 Wh/kg 和 1000 W/kg 的最大比电容、能量密度和功率密度。我们认为这些材料具有显着的用于轻量级和灵活的 SCs 的潜力。