Iron oxide (Fe₂O₃) has drawn much attention because of its high theoretical capacitance, wide operating potential window, low cost, natural abundance, and environmental friendliness. However, the inferior conductivity and insufficient ionic diffusion rate of a simple Fe₂O₃ electrode leading to the low specific capacitance and poor rate performance of supercapacitors have impeded its applications. In this work, we report a facile and cost-effective method to directly grow MIL-88-Fe metal–organic framework (MOF) derived spindle-like α-Fe₂O₃@C on oxidized carbon nanotube fiber (S-α-Fe₂O₃@C/OCNTF). The S-α-Fe₂O₃@C/OCNTF electrode is demonstrated with a high areal capacitance of 1232.4 mF/cm² at a current density of 2 mA/cm² and considerable rate capability with capacitance retention of 63% at a current density of 20 mA/cm² and is well matched with the cathode of the Na-doped MnO₂ nanosheets on CNTF (Na-MnO₂ NSs/CNTF). The electrochemical test results show that the S-α-Fe₂O₃@C/OCNTF//Na-MnO₂ NSs/CNTF asymmetric supercapacitors possess a high specific capacitance of 201.3 mF/cm² and an exceptional energy density of 135.3 μWh/cm². Thus, MIL-88-Fe MOF derived S-α-Fe₂O₃@C will be a promising anode for applications in next-generation wearable asymmetric supercapacitors.

中文翻译：

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金属有机骨架衍生的纺锤状碳股份有限公司的α-Fe ₂ Ø ₃在碳纳米管纤维生成作为阳极的高性能耐磨不对称超级电容器

氧化铁（Fe ₂ O ₃）由于其高的理论电容，宽的工作电势范围，低成本，自然丰度和环境友好性而备受关注。但是，简单的Fe ₂ O ₃电极的导电性差，离子扩散率不足，导致比电容低，超级电容器的倍率性能差，阻碍了其应用。在这项工作中，我们报告一个浅显的和成本有效的方法，以直接生长MIL-88 -铁金属-有机构架（MOF）衍生的纺锤状的α-Fe ₂ ö ₃ @C对氧化的碳纳米管纤维（S-α- Fe ₂ O ₃ @ C / OCNTF）。在S-的α-Fe ₂证明了O ₃ @ C / OCNTF电极在2 mA / cm ²的电流密度下具有1232.4 mF / cm ²的高面积电容，在20 mA / cm ²的电流密度下具有相当大的倍率容量和63％的电容保持率并与CNTF上的Na掺杂MnO ₂纳米片的阴极（Na-MnO ₂ NSs / CNTF）很好地匹配。电化学测试结果表明，S-的α-Fe ₂ ö ₃ @ C / OCNTF //钠的MnO ₂ NSS / CNTF不对称超级电容器具有的201.3 MF / cm的高比电容²和135.3一个特殊的能量密度μWh/厘米²。因此，MIL-88 -铁MOF衍生S-的α-Fe ₂ ö ₃ @C将成为下一代可佩戴不对称超级电容器应用的有前途的阳极。