Full-Component Wood-based Carbon Aerogel As Energy Storage Material For Packaging

In recent years,intelligent packaging has become the main layout and development direction of packaging enterprises.They have increased their efforts and continuously launched new intelligent packaging innovative service modes and commodities in the market.Among them,the energy storage device becomes the driving device for building the packaging intelligent system.In order to overcome the problems of low energy density,a Liquefied wood carbon aerogel(LWCA)with adjustable pore size was prepared from Liquefied wood by sol-gel,solvent replacement,carbonization and activation technology.The nano microstructure of carbon aerogel system could be controlled by controlling the amount of catalyst added.Liquefied wood carbon aerogels / polypyrrole(LWCA-PPy)and in-situ grown Liquefied wood carbon aerogels/β-Ni S(LWCA-Ni S)composite energy storage material were prepared by in-situ polymerization and in-situ growth on LWCA carbon aerogel skeleton.The micro morphology,graphitization,crystallinity,functional group characteristics,pore structure and electrochemical properties of energy storage materials were studied in detail.The results show that:(1)The content of catalyst(hexamethylenetetramine)can directionally adjust the micro pore structure of LWCA.A large number of catalysts could promote the formation of carbon aerogels pore structure,but excessive catalyst would cause excessive cross-linking of the system.After the material was carbonized and activated,it will produce "cavity".LWCA not only had a typical graphitized structure,but also BET analysis showed that LWCA presented a large number of mesopores.The large specific surface area and pore volume of LWCA-3 were conducive to the storage of electrolyte ions.Electrochemical performance analysis showed that the specific capacitance of carbon aerogels first increased and then decreased with the increase of catalyst content,which was attributed to the influence of different network structures of carbon aerogels on electrochemical performance.LWCA-3 had the best performance in all aspects,with a maximum specific capacitance of 154.15 F/g.After 4500 times of constant current charge and discharge,the retention rate could reached 92.62%,which had the widest application prospect.(2)The effects of different PPy loading on LWCA-PPy were studied in order to find the best loading concentration of LWCA-PPy electrode material.The open network structure of LWCA-3 was conducive to the inward penetration of pyrrole,avoids the accumulation of PPy particles on the skeleton surface,and reduced the diffusion resistance of electrolyte on the internal surface during application.PPy has the characteristics of low cost and high pseudo capacitance,which can improve the capacitance performance of LWCA.With the increased of PPy load,the pores were gradually blocked,which was not conducive to the infiltration of electrolyte.BET results showed that the specific surface area and pore volume decreased significantly after PPy loading on LWCA.The content of N in carbon aerogels far exceeds the content of N in LWCA.Finally,through the analysis of electrochemical performance,LWCA-ppy-65 showed a high specific capacitance of421.45 F/g due to its excellent pore structure and PPy functional groups,which was more than 1.7 times higher than that of pure LWCA,and the specific capacitance retention was still 82.9% after 5000 charges and discharges.(3)Researched the effects of β-Ni S raw material concentration and loading concentration on LWCA-Ni S.As an electron acceptor,the framework structure of LWCA-3system could accelerate the migration of charges and ions,and retarding charge recombination.Materials could greatly improved low conductivity and self aggregation ofβ-Ni S microspheres during charge and discharge,and increased the cyclic stability of pseudocapacitor materials.At the same time,it had a large surface area,which could fully expose the active edge position,so as to improved the capacitance.The surface of β-Ni S microspheres presented nano porous structure,which promoted the access of electrolyte.When the loading amount of β-Ni S microspheres was too much,it would also blocked the pore structure in the system skeleton and reduced the electrochemical performance of the material.LWCA-Ni S-10 had a reasonable pore structure and loading density.The specific capacitance at 1A/g current density was 887.08F/g,and the specific capacitance retention rate after 2000 charging and discharging was as high as 63.06%.