FULL PAPER www.afm-journal.de © 2019 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim 1809004 (1 of 11) Multicomponent Hierarchical Cu-Doped NiCo-LDH/ CuO Double Arrays for Ultralong-Life Hybrid Fiber Supercapacitor Yaqing Guo, Xufeng Hong, Yao Wang, Qi Li, Jiashen Meng, Runtao Dai, Xiong Liu, Liang He,* and Liqiang Mai* Fiber supercapacitors have aroused great interest in the field of portable and wearable electronic devices. However, the restrained surface area of fibers and limited reaction kinetics of active materials are unfavorable for performance enhancement. Herein, an efficient multicomponent hierarchical structure is constructed by integrating the Cu-doped cobalt copper carbonate hydroxide@nickel cobalt layered double hydroxide (CCCH@NiCo-LDH) core– shell nanowire arrays (NWAs) on Cu fibers with highly conductive Au-modi- fied CuO nanosheets (CCCH@NiCo-LDH NWAs@Au–CuO/Cu) via a novel in situ corrosion growth method. This multicomponent hierarchical structure contributes to a large accessible surface area, which results in sufficient per- meation of the electrolyte. The Cu dopant could reduce the work function and facilitate fast charge transfer kinetics. Therefore, the effective ion diffusion and electron conduction will facilitate the electrochemical reaction kinetics of the electrode. Benefiting from this unique structure, the electrode delivers a high specific capacitance (1.97 F cm -2 /1237 F g -1 /193.3 mAh g -1 ) and cycling stability (90.8% after 30 000 cycles), exhibiting superb performance compared with most oxide-based fiber electrodes. Furthermore, the hybrid fiber super- capacitor of CCCH@NiCo-LDH NWAs@Au–CuO/Cu//VN/carbon fibers is fabricated, providing a remarkable maximal energy density of 34.97 Wh kg -1 and a power density of 13.86 kW kg -1 , exhibiting a great potential in high- performance fiber-shape energy-related systems. DOI: 10.1002/adfm.201809004 Y. Q. Guo, X. F. Hong, Y. Wang, Prof. Q. Li, J. S. Meng, R. T. Dai, X. Liu, Prof. L. He, Prof. L. Q. Mai State Key Laboratory of Advanced Technology for Materials Synthesis and Processing International School of Materials Science and Engineering Wuhan University of Technology Wuhan 430070, P. R. China E-mail: hel@whut.edu.cn; mlq518@whut.edu.cn R. T. Dai School of Journalism and Communication Tsinghua University Beijing 100084, P. R. China Prof. L. He Department of Materials Science and NanoEngineering Rice University Houston, TX 77005, USA The ORCID identification number(s) for the author(s) of this article can be found under https://doi.org/10.1002/adfm.201809004. 1. Introduction Fiber supercapacitors (SCs) have been explosively developed as a significant kind of energy storage device in portable and wearable electronic equipment. [1,2] Similar to other common SCs, the fiber SCs deliver relatively high power output, faster charge/discharge, yet have low energy density. [3,4] Compared with the traditional on-chip SCs, the fiber SCs are more flex- ible and compatible for bending, twisting, and stretching on anomalous substrates, and can be easily adapted to high defor- mation in wearable electronic devices. [1,5,6] However, the energy density of conven- tional fiber SCs is generally much lower than that of fiber batteries, such as fiber lithium-ion batteries. [7] Developing hybrid fiber SCs with a capacitor-type electrode as a power source and a battery-like electrode as an energy source is one of the most efficient ways to enhance the capacitance of fiber SCs. However, multiple efficient strategies such as complex synthesis of active materials for battery-like electrode are difficult to be conducted due to the limitation of fiber-like device structure. Besides, this kind of SC always suffers from poor rate capability and cycling stability. [8–10] Furthermore, a high-performance cur- rent collector with optimized structure like three dimensional (3D) framework is in favor of improving reaction kinetics and areal mass loading of active materials. [11,12] Therefore, opti- mizing performance of active material and constructing novel electrode structure with an efficient and exercisable method for hybrid fiber SCs with high energy density and cycling stability are highly required. [13–15] Recently, nickel–cobalt layered double hydroxides (NiCo- LDHs) as electroactive materials have been widely investigated on account of their high theoretical capacitance (3000 F g -1 ), low cost, and environmental friendliness. [16] However, the rate of Faradaic reactions in bulk of battery-like electrode is much slower than that on the surface, accompanying with low electrical conductivity of the NiCo-LDH, leading to a lower rate capability. [17–21] Additionally, the NiCo-LDH suffers from inferior cycling stability. [22] Recently, Liu et al. reported that Fiber Supercapacitors Adv. Funct. Mater. 2019, 1809004