Effects Of Additives On The Interface And Properties Of PEO-based All-solid Lithium Batteries

The development of new energy technologies has been paid much attention to,and as one of the most important fields of electrochemical conversion energy has been developing rapidly in recent years.Rechargeable lithium ion batteries are one of the most important ones.Lithium-ion batteries have the advantages of small size,large capacity,and high voltage.However,due to the use of liquid electrolytes and unstable electrolytes,they are flammable and explosive,which make the safety of lithium-ion batteries face serious challenges.The all-solid-state lithium battery that uses a non-flammable solid electrolyte are capable of solving the safety problem of lithium-ion batteries and can also achieve the characteristics of high energy / power density.Therefore,all-solid-state lithium-ion batteries have received increasing attention.Aiming at the problems of high interface impedance and instability of interfacial performance appearing in the current research of all solid electrolytes,this paper builds high-stability,high-safety and high-performance Solid polymer lithium batteries by exploring the effects of additives with different properties on the interface and performance of polymer solid electrolytes.The key research contents are as follows:First,the interface problem of all solid-state lithium-ion batteries inhibits the transport capacity of lithium ions,which leads to a decrease in the coulomb efficiency and power density,and rapid capacity decay of solid-state lithium-ion batteries.Based on the characteristics of conductive materials,non-conductive materials,and electrochemical reactions,graphene oxide,Al₂O₃,SiO₂,1,4-dihydroxyanthraquinone,and pyrrole were selected respectively.The microstructure of the solid polymer electrolyte and the effects of different substances on the interface resistance and electrochemical performance of the polymer electrolyte were studied in comparison.Among the inorganic additives,Al₂O₃ has the greatest impact on the interface.After100 cycles of charge and discharge,the battery interface resistance was reduced from3846 ? to 227 ?,and the interface charge transfer resistance of the battery was reduced from 21772 ? to 1093 ?.Among the organic additives,pyrrole has the largest effect on the interface.After 100 cycles of charge and discharge,the battery's interface resistance is reduced from 5089 ? to 195 ?,and the interface charge transferresistance of the battery is reduced from 31396 ? to 1200 ?.The best selected additive,pyrrole,can not only improve the ionic conductivity but also maintain the stability of the electrode-electrolyte interface.Second,the effect of the additive pyrrole on the performance of all solid-state lithium-ion batteries was further explored.The mechanism of pyrrole molecules,improving the interface and cyclic stability,was analyzed.The electrochemical method is used to polarize the pyrrole between the double layers inside the battery,which allows the polymerization of pyrrole to form polypyrrole.Polypyrrole is a conductive material.By this method,the resistance of the battery is reduced,thereby improving the overall performance of the battery.In addition,the conditions for the polymerization of pyrrole were also investigated,and the electrochemical performance tests were conducted to obtain the optimal dosage of the additives.