NiCo-LDH/CNW/CC三维结构复合电极及其电化学性能研究

NiCo-LDH/CNW/CC three-dimensional structure composite electrode and its electrochemical performance

NiCo-LDH具有优异的电化学性能,但自身易团聚且导电性差,导致其作为电极使用时本征电化学性能无法体现,常见的解决办法是将其分散负载于导电性好、比表面积大的惰性基体表面来使用。本文首次利用微波等离子体化学气相沉积技术先在具有大比表面积、导电性好且惰性强的碳布(CC)表面制备具有三维多孔结构的碳纳米墙(CNW)以进一步提高其比表面积和对粒子的负载性,再将NiCo-LDH通过电沉积法分散负载于CNW表面形成NiCo-LDH/CNW/CC三维结构复合电极。采用SEM观察复合电极的微观结构,同时通过Raman和XRD技术分析复合电极的材料组成,最后进一步使用电化学技术研究复合电极在三电极体系下的电化学性能。结果表明,CNW涂覆于CC表面作为载体能有效抑制NiCo-LDH的团聚,增加NiCo-LDH的分散性和有效暴露面积,所形成的NiCo-LDH/CNW/CC三维结构复合电极在2 mV·s^(-1)扫速下比电容是NiCo-LDH/CC的1.4倍;在电流密度为2 mA·cm^(-2)时,比电容高达3.9 F·cm^(-2),同时展现出优异的倍率性能;且经10000次循环后,电容保持率仍达70%,远优于NiCo-LDH/CC的循环稳定性,表明制备形成的NiCo-LDH/CNW/CC复合电极可充分发挥NiCo-LDH的电化学特性、CNW三维多孔结构良好负载性和CC优异的机械、电学性能,是一种极具应用潜力的新型电极材料。

NiCo-LDH has excellent electrochemical properties,but is easy to agglomerate and has poor electrical conductivity,so its intrinsic electrochemical properties cannot be reflected when used as an electrode.The standard solution is to disperse and load it on the surface of an inert substrate with good conductivity and a large specific surface area.In this paper,carbon nanowalls(CNW)with a three-dimensional porous structure were prepared for the first time on the surface of carbon cloth(CC)with a large specific surface area,good conductivity,and inertness by microwave plasma chemical vapor deposition technology further to improve its specific surface area and particle loading.NiCo-LDH was dispersed and supported on the CNW surface by electrodeposition to form a NiCo-LDH/CNW/CC three-dimensional composite electrode.The microstructure of the composite electrode was observed by SEM,and the material composition of the composite electrode was analyzed by Raman and XRD techniques.Finally,the electrochemical performance of the composite electrode in the three-electrode system was further studied by electrochemical technology.The results show that CNW coated on CC surface as a carrier can effectively inhibit the agglomeration of NiCo-LDH and increase the dispersion and effective exposure area of NiCo-LDH.The formed NiCo-LDH/CNW/CC three-dimensional composite electrode has a specific capacitance of 1.4 times NiCo-LDH/CC at a scan rate of 2 mV/s.At a current density of 2 mA/cm^(2),the specific capacitance is as high as 3.9 F/cm^(2) while exhibiting excellent rate performance.Moreover,after 10000 cycles,the capacitance retention rate is still up to 70%,which is far better than the cycling stability of NiCo-LDH/CC,indicating that the prepared NiCo-LDH/CNW/CC composite electrode can give full play to the electrochemical performance of NiCo-LDH.It is a new type of electrode material with excellent application potential due to its excellent electrical properties,good loadability of CNW three-dimensional porous structure,and excellent mechanical and electrical properties of CC.