1. Hierarchical NiCoP nanosheet arrays with enhanced electrochemical properties for high-performance wearable hybrid capacitors
- Author
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Yagang Yao, Liyan Xie, Zezhou Zhu, Bing He, Zhenyu Zhou, Qijun Zong, Juan Sun, Songfeng E, and Qichong Zhang
- Subjects
Materials science ,Vanadium nitride ,02 engineering and technology ,Carbon nanotube ,010402 general chemistry ,01 natural sciences ,Capacitance ,law.invention ,chemistry.chemical_compound ,law ,Materials Chemistry ,Fiber ,Nanosheet ,business.industry ,Mechanical Engineering ,Metals and Alloys ,021001 nanoscience & nanotechnology ,0104 chemical sciences ,Capacitor ,chemistry ,Mechanics of Materials ,Electrode ,Optoelectronics ,0210 nano-technology ,business ,Current density - Abstract
Transition metal phosphides (TMPs) are battery-typed materials with superior conductivity and redox activity, thereby making them promising in fiber-shaped hybrid capacitors (FSHCs). Yet designed synthesis of nanostructured TMPs on conductive fiber substrate as binder-free electrode is essential to improve their electrochemical performance. This work proposes an efficient strategy to directly grow hierarchical NiCoP nanosheet arrays (NSAs) on carbon nanotube fibers (CNTFs) by using a hydrothermal process and subsequent gas-solid phosphorization. Benefiting from the ordered nanosheet structure, the NiCoP/CNTF electrode exhibits a specific capacity of 0.711 mAh cm−2 at a current density of 1 mA cm−2. Matching this electrode with a negative electrode of CNTF supported vanadium nitride (VN) NSAs, we fabricated a high-performance twisted FSHC with a maximum operating voltage of 1.6 V. Owing to the ultrahigh electrochemical performance of the hybrid fiber electrodes, the FSHC device delivers a high specific capacitance of 325.6 mF cm−2 (108.53 F cm−3) at the current density of 1 mA cm−2, and achieves an energy density of 115.78 μWh cm−2. Moreover, it displays excellent flexibility with negligible capacitance loss after 5000 bending cycles. Thus, this work elucidates a feasible route to construct NiCoP-based fiber electrodes for wearable energy storage devices.
- Published
- 2019