Lignosulfonate/MXene Composite And Its Application In Supercapacitors

In recent years,with the rapid development of new energy vehicles,portable flexible electronic devices,and large integrated power grids,the development of electrochemical energy storage devices with both high power and energy density has attracted more attention.Supercapacitor is an energy storage device with energy and power density between secondary batteries and traditional capacitors.It has both high power density,fast charge and discharge rates,long cycle life,and a wide operating temperature range.But compared with the traditional secondary battery,its energy density needs to be further improved.MXenes is a type of transition metal carbon/nitride,which has metal-like ultra-high conductivity and a large theoretical specific capacitance.However,as an electrode material,re-stacking and the narrow working potential range limit its wide application.As an industrial by-product,lignosulfonate is low in cost,large in yield,and rich in phenol-quinone groups.This article uses lignosulfonate,MXene?Ti₃C₂T_x?and r GO to prepare supercapacitor electrode materials with excellent electrochemical performance through different self-assembly processes.The main research contents include:1.Preparation of lignosulfonate/MXene two-dimensional self-assembly composites and their application as supercapacitor electrode materials.lignosulfonate/MXene composite membrane material was prepared by lignosulfonate?LS?and MXene?Ti₃C₂T_x?through vacuum filtration self-assembly process.The effects of the ratio of LS to MXene and the ultrasonic time on the electrochemical performance of lignosulfonate/MXene composites were discussed.The X-ray diffraction results show that the interlayer distance of MXene gradually increases with the increase of the amount of LS,which indicates that LS prevents the re-stacking of MXene.The three-electrode test system found that when the mass ratio of LS to MXene was 2:8 and the ultrasonic time was 10minutes,the specific capacitance of the composite thin-film electrode at scan of 2 m V s^-1 was 310 F g^-1,and the specific capacitance still has 185 F g^-1 even at scan of 100 m V s^-1.2.Preparation of lignosulfonate/MXene/reduced graphene oxide?MLSG?aerogel and its performance as a supercapacitor electrode.Herein,for the first time,the lignosulfonate?LS?modified and assembled MXene?Ti₃C₂T_x?-r GO 3D porous?MLSG?aerogel is reported.As a supercapacitor electrode,the MLSG aerogel electrode exhibits higher specific capacitance(386 F g^-1at scan of 2 m V s^-1),and excellent rate performance(241 F g^-1 at scan of 100 m V s^-1),even when the mass-loading reaches 5.1 mg cm^-2.