Preparation And Properties Of Flexible Electrode Based On Aramid Nanofiber

Flexible supercapacitors have the advantages of high-power density,fast charge and discharge,long cycle life,and deformability.They are important energy storage devices for wearable electronic products.Flexible self-supporting electrode materials are the basic components of supercapacitors.Portable,lightweight,flexible,good electrochemical performance and strong durability.However,the current flexible electrode materials still have problems such as low energy density and poor mechanical properties,which greatly limits the practical application range of flexible electrode materials.Graphene(RGO)and MXene are typical two-dimensional materials with good electrical conductivity,and exhibit broad application prospects in electrode materials.Aramid nanofibers(ANFs)with high mechanical strength are ideal substrate materials.Based on this,RGO and MXene are selected as conductive active materials,and ANFs were selected as nanofillers to reinforce RGO and MXene,respectively,in this thesis.By adding different amounts of ANFs to,develop their reinforcing effects,composite films with high mechanical properties and high electrochemical properties are prepared for electrode materials.The main work and results are as follows:Through blending ANFs/DMSO and GO/DMSO dispersions,GO/ANFs composite membranes with ANFs content of 5%,10%,20%,and 30%were prepared,and they were reduced to RGO/ANFs using hydroiodic acid(HI).The influence of ANFs content on the mechanical properties and electrochemical performance of RGO/ANFs composite membrane was thoroughly investigated.The results show that when the content of ANFs is 10%(mass percentage),the tensile strength of the RGO/ANFs composite film is 72.5MPa,and the specific capacitance reaches 125.6 F/g at a current density of 1 m A/cm~2.After 3 000 constant current charge-discharge cycle tests under the current density of 2 m A/cm~2,the capacitance retention rate was 86%.Using RGO/ANFs thin film as flexible substrate,aniline was deposited on RGO/ANFs thin film uniformly by electrochemical deposition method.The effect of electrochemical deposition time on the electrochemical performance of RGO/ANFs/polyaniline(PANI)film was studied.The results show that after 10 min of potentiostatic deposition,the RGO/ANFs/PANI composite film with ANFs content of10%has an area specific capacitance of 500.7 m F/cm~2 at a current density of 1 m A/cm~2.After 3 000 constant current charge-discharge cycle tests under the current density of 2m A/cm~2,the capacitance retention rate was 72%.MXene was prepared by LiF/HCI etching method.MXene/ANFs composite membranes with ANF content of 10%,20%and 30%were prepared by blending method.The results show that when the ANFs content is 10%,the MXene/ANFs composite film has a tensile strength of 64.6 MPa,and an area specific capacitance of280.3 m F/cm~2 at a current density of 1 m A/cm~2.After 3 000 constant current charge-discharge cycle tests under the current density of 2 m A/cm~2,the capacitance retention rate was 83%.