Preparation And Properties Of Bacterial Cellulose/graphene/polyaniline Ternary Flexible Electrode Materials

Supercapacitor is a novel energy storage device between chemical power source and traditional capacitor.It has aroused wide attention from many scholars at home and abroad because of its numerous advantages such as high charge and discharge speed,high power density,good cycling stability,low maintenance cost and environmental friendliness.As an important part of the capacitor,the properties of the electrode material,to a large extent,determine the performance of the capacitor.Therefore,it is of great theoretical and practical significance to explore the electrode materials with excelent electrochemical properties.In this paper,bacterial cellulose/graphene?BC/GE?composites were fabricated by membrane culture method.Bacterial cellulose/graphene/polyaniline?BC/GE/PANI?composites with three-dimensional porous structure were prepared by in-situ chemical polymerization.The synthesis conditions of BC/GE/PANI composites were optimized by adjusting the polymerization temperature and time.Results indicated the BC/GE/PANI-5 composites with fiber diameter of 105±9.6 nm,homogeneous morphology and abundant pore structure could be obtained by continuous reaction at5°C for 6 h.XRD analysis showed the crystallinity of BC/GE was obviously affected by the GE content,and the crystallinity index decreased from 91%to 69%when the content of GE increased from 0 to 11.8 wt%.The BET surface area measurements revealed the BC/GE/PANI composites had a specific surface area of 79.3 m²·g^-1 and mesopore volume of 0.29 cm³·g^-1 when the GE content was 3.6 wt%.The wettability test showed that the addition of GE and PANI,to a certain extent,reduced the hydrophilicity of the composites.The contact angel of BC/GE/PANI-5 composites increased from 39.2°of BC to 42.8°,which is beneficial to improve the electrochemical properties of materials.Based on the preparation of BC/GE/PANI composites,the mechanical,electrical and electrochemical properties of the composites were systematically studied.Mechanical tests showed that the addition of GE and PANI significantly improved the mechanical strength of BC,while the composite still maintained excellent mechanical flexibility.Compared with BC,the tensile strength and elastic modulus of BC/GE/PANI-5 increased by 60.76%and 169.88%,respectively,while the elongation at break decreased by 49.64%.The electrical conductivity of BC/GE/PANI composites significantly improved after the introduction of GE.When the reaction time was 6 h and the content of GE was 3.6 wt%,the BC/GE/PANI-5 composites had the highest electrical conductivity to 1.66 S·cm^-1.The electrochemical tests showed that the specific capacity,cycle stability and energy density of BC/GE/PANI composites improved significantly after the addition of GE.The BC/GE/PANI-5 had a specific capacity of 625 F·g^-1 at a current density of 1 A·g^-1,which was 2.5 times higher than that of BC/PANI.After 1000 cycles,the BC/GE/PANI-5 had a capacity retention rate of 82.2%,which was 23.9%higher than that of BC/PANI.The maximum energy density of BC/GE/PANI-5 was 105 Wh·kg^-1,which was 4.8 times higher than that of BC/PANI,and significantly higher than those reported in most literatures.Thus,the BC/GE/PANI composites prepared in this paper show excellent electrochemical properties,and have wide application prospects in the field of flexible electrode materials.