Preparation Of Laser-induced Graphene/Nickel-cobalt Hydroxide And Performance Study For Supercapacitor Electrode Material

With the ever-increasing crisis continues on the world,efficient energy storage technologies are increasingly valued by people in their lives and production.Among various energy storage devices,supercapacitors,as a new type of energy storage devices,play a key role in many efficient energy storage areas and show great application prospects owing to their advantages of high power density,fast charge and discharge speed,long cycle life and high safety performance.Electrode materials are one of the key factors determining the performance of supercapacitors.The performance of supercapacitors can be optimized through rational electrode material structure design and components ratio design.The research content of this paper is mainly based on electrode materials for supercapacitors,involving graphene electrode materials and nickel-cobalt hydroxides pseudocapacitive materials.In this study,an efficient and rapid laser induction technology was used to complete the preparation of graphene,which overcomes the drawbacks of traditional graphene preparation methods that are complicated and costly.Then,laser-induced graphene(LIG)was used as a conductive support substrate to grow nickel-cobalt layered double metal hydroxide(NC-LDHs)with high specific capacitance by electrochemical deposition method for NC-LDHs/LIG composite electrode material preparation.Scanning electron microscopy(SEM),transmission electron microscopy(TEM),Raman spectroscopy(Raman),X-ray diffraction(XRD),Fourier Transform Infrared Spectrometer(FTIR)and specific surface area testing were used to anlyze the morphology and structure of electrode materials.The electrochemical performance was tested on electrochemical workstation.Based on this,a flexible supercapacitor was assembled using PVA/KOH gel electrolyte and its electrochemical performance was studied.The main research work and conclusions of this paper are as follows:The laser-induced technique was used for efficient graphene preparation on the alkali-resistant polyphenylene sulfide(PPS)precursor.At the same time,the laser parameters were adjusted to improve the morphology and conductivity of LIG.The obtained LIG exhibits fibers structure,which is beneficial to the direction transfer of electrons and the efficient transmission of ions in the electrochemical reaction.The laser-induced graphene prepared on the PPS film can make NC-LDHs materials with stable specific capacitance only in alkaline electrolytes successfully applied in the field of LIG.Using the PPS-supported LIG fibers as a conductive support,an NC-LDHs/LIG composite electrode was prepared by electrochemical deposition method.And LIG fibers structure effectively weakened the agglomeration of NC-LDHs nanosheets.At the same time,there are many through-holes on the prepared NC-LDHs nanosheets.The presence of these through-holes is beneficial to increase the specific surface area and electrochemical active sites of NC-LDHs.Then,the molar ratio of Ni and Co in the NC-LDHs/LIG composite material was adjusted.In the seven samples prepared with different molar ratios of Ni:Co,NC-LDHs/LIG composite material with Ni:Co=2:1 shows the best morphology and electrochemical performance,which is selected by morphology and electrochemical characterization.Next,electrochemical tests were performed for NC-LDHs/LIG with Ni/Co=2:1.Its maximum specific capacity was 4503 m F/cm~2 and it showed good rate performance and cycle stability.With the help of the patterning features of laser-induced technology,a graphene-based microsupercapacitors(LIG-MSC)was fabricated on flexible PPS films.It still maintains 91%of the initial capacitance after 8000 charge and discharge cycles,meaning a long cycle life.Based on the NC-LDHs/LIG composite electrode material,an asymmetric supercapacitor was assembled,which achieved excellent electrochemical performance with an area specific capacitance of 699.4 m F/cm~2,a maximum energy density of 219μWh/cm~2,and a maximum power density of 2640μW/cm~2.In one word,this have used high-efficiency laser-induced technology to prepare graphene and composited it with NC-LDHs with high specific capacitance for NC-LDHs/LIG electrode material with excellent performance preparation.The assembled flexible supercapacitor has obtained excellent electrochemical performance and has shown great application prospects in the field of energy storage.