用于超级电容器的柔性多孔富氮碳电极的制备与性能

Fabrication and characterization analysis of flexible porous nitrogen-doped carbon-based supercapacitor electrodes

柔性固态超级电容器作为一种新型能量存储器件,与传统平行板电容器相比可以达到更高的能量密度,相比普通电池则具有更大的功率密度和循环使用寿命,展示出良好的电化学性能,并具有高功率密度和循环稳定性好等优点,因而受到越来越多的关注,在可穿戴设备、柔性电子器件等诸多领域有着广泛的应用.目前,柔性电极材料的选取与制备是柔性超级电容器研究中十分活跃的方向,其中,碳基电极因为具有良好的电导性能、循环稳定性、高功率密度等特点,被国内外学术界广泛认可.本文提出了一种高效、简便制备碳基电极的方法,得到多孔富氮纳米片结构的碳电极,并对不同实验条件下的碳化电极样品做了全面的表征分析与性能测试,得到了较为理想的柔性碳化电极样品,其质量比电容达26 F/g,面积比电容达226 mF/cm2,等效串联阻抗仅为4?,具有很好的电化学性能.

Supercapacitor as a new-type energy storage device has attracted increasing interests, because it can provide substantially higher specific/volumetric energy density compared to conventional capacitors, and higher power density and longer cycling lifetime compared to Li-ion batteries. Therefore, it shows great promise as green energy storage device for back-up energy systems and electronic vehicles. Among all kinds of supercapacitors, flexible solid-state supercapacitor, which consists of flexible electrodes, solid-state electrolyte and separator, has attracted much attention due to its potential abilities in wearable electronics and flexible devices. Numerous efforts have been devoted to fabricate flexible electrodes because the fundamental limit of energy storage capability is largely determined by the electrode material. Therefore, how to fabricate suitable flexible electrodes alerts significant influence on supercapacitors＇ performance. Compared to pseudocapacitive materials, carbon-based materials have been widely investigated for flexible electrodes due to their good electrical conductivity, excellent cycling stability, high power density and outstanding mechanical properties. In this work, an effective and feasible method to fabricate carbon-based electrode for the fabrication of flexible and high-performance supercapacitors has been proposed. In order to find the relatively suitable electrode, samples under different experimental conditions have been tested and analyzed systematically. Through the simultaneous activation and carbonization process of the biomass-derived natural silk, all of these carbon-based electrodes have a few features, like hierarchical porous, rich N-doped and carbon nanosheet structure. The as-obtained electrodes show favorable capabilities for electrochemical energy storage. The specific/mass capacitor of the best carbon-based electrode can achieve 226 mF/cm2 and 26 F/g, respectively, and the equivalent series resistance of it is only 4 fL thus showing satisfactory electrochemical performance. In conclusion, the excellent capacitance performance of the ultralight and flexible nanomaterials makes them promising candidates as electrode materials. Attributed to the good flexibility and ultralight weight, this proposed electrodes can be directly fabricated into flexible solid-state supercapacitor without any binder and conductive agents.