Preparation And Performance Study Of Flexible Supercapacitors

With the emergence of novel concept, such as flexible displays, portable and wearable devices, and the related products have been realized, the flexible electronic technology,considered as one of the most competitive and promising technique in 21 st century, will change human life to the large extent. The hunger for high-tech and personalized products can accelerate the research and production of the flexible electronic products which will become the growing trend in the future. Flexible power supply, the basis energy supply source for the flexible electronic products, should not only ensure the excellent electrochemical performance,but promise to work normally under the mechanical deformation conditions. The flexible supercapacitor, one of the flexible power suppliers, has attracted more and more researcher's interests and become one of the promising research fields. The structure and electrode materials, two key factors that affect the performance of the flexible supercapacitors, are the breakthrough to solve the current problems existed in flexible supercapacitors. In this paper,we focus on fabricating the low-cost electrode materials, designing the structure of the electrodes, and exploring the facile and available methods to prepare the flexible solid-state supercapacitors, the main research contents are introduced as follows:1. The fabrication and performance characterization of the flexible Ni/MnO2-FP electrode.First of all, the hybrid and conductive paper Ni(I)-FP was prepared by traditional electroless plating process, which changed FP from insulation to electric conduction. Then,the followed electroplating Ni technique was performed to further increase the electric conductivity of FP and fabricate the flexible substrate Ni(II)-FP. Finally, the nanosheet-like MnO2 layer was coated on the surface of Ni(II)-FP by electrodeposition method, after which the highly flexible and conductive Ni/MnO2-FP electrode was finished. We systematically studied the electrochemical performance of the Ni/MnO2-FP electrode, the data showed that the electric conductivity(?) of the Ni(I)-FP was 1.2×103 S/m after electroless plating and the ?of the Ni(II)-FP achieve the high level of 1.5×105 S/m after electroplating. The optimal electrodeposition time of MnO2 was 10 min through comparing the microstructure and specific capacitance of different Ni/MnO2-FP, and the as-prepared Ni/MnO2(10)-FP exhibited the excellent specific capacitance of 1900 mF/cm2 at scan rate of 5 mV/s.2. The fabrication and performance characterization of the flexible Ni/AC-FP electrode.We prepared the flexible Ni/AC-FP electrode through physically coating AC on highly conductive substrate Ni(II)-FP, and researched electrochemical performance and feasibility of Ni/AC-FP electrode. The results showed that Ni/AC-FP electrode presented well performance and the physically coating method was available.3. The fabrication and performance characterization of the flexible NMA supercapacitor.The flexible asymmetrical all-solid-state NMA supercapacitor with high performance was assembled with Ni/MnO2-FP as the positive electrode and Ni/AC-FP as negative electrode, separated by PVA-Na2SO4 solid-state electrolyte. We studied the NMA supercapacitor's electrochemical performance, mechanical flexibility and bending cycling stability. The data showed that as-fabricated NMA supercapacitor could be used as a small flexible power source, the energy density of which was 0.78 mWh/cm3, furthermore, NMA supercapacitor exhibited the superior flexibility and well bending cycling stability.