Study On High Performance Lithium Metal Anode Constructed With Printable 3D Current Collection

At present,traditional energy sources such as oil and coal are facing the risk of shortage.People are looking for new alternatives to replace these fossil fuels.Lithium metal batteries（LMBs）has become one of the most popular energy storage devices because of the ultrahigh theoretical specific capacity and the lowest electrochemical potential of lithium（Li）metal.However,there are still several critical challenges for Li metal anodes,including uncontrolled growth of Li dendrite,unstable solid–electrolyte interface（SEI）and excessive volume change during Li depositing.The mainstream solution to solve these problems is to design a special three-dimensional（3D）porous structure to replace the traditional copper（Cu）foil current collector.Among them,the mesh structure exhibits unique advantages owing to its own structural characteristics of easy adjustment.However,most of the methods for preparing mesh current collectors are cumbersome and far away from the goal of commercialization,so it is necessary to explore a new simple and efficient method.Compared with traditional laboratory preparation methods（such as template method,dealloying method,etc.）,screen printing technology has attracted much attention due to its advantages of low cost,large area,patterning,and flexible compatibility,which can meet the conditions for commercialization.So,it is of great significance to study the preparation of mesh current collectors by screen printing.In this paper,mesh current collectors were prepared by a simple screen-printing method with using traditional current collector material of copper（Cu）,traditional lithiophilic material of silver（Ag）and cheap nonmetallic material of silicon dioxide（Si O₂）.Moreover,the growth and stabilization mechanism of Li dendrites with using different mesh structures composed of various materials were discussed,which provided a new idea for the commercialization of Li metal anode current collectors.The main contents of the theis are summarized as follows:（1）A current collector with periodic Cu mesh was prepared by screen printing technology.Periodic mesh can not only reduce the local effective current density of Li metal anode with delayed Li dendrite formation,but also can provide Li storage space to avoid the instability of SEI film caused by the big volume change of Li and serious safety problem induced by battery short circuit.（2）A current collector with periodic Ag mesh was prepared by screen printing technology.Ag nanoparticles have both high lithiophilicity and conductivity.Therefore,Ag mesh not only has the function of Cu mesh structure to adjust the current density,but also has the characteristics of lithiophilic material to make Li deposition more uniform.Besides,Ag mesh current collector exhibits small nucleation overpotential,long cycle life and significant inhibition of Li dendrites.（3）A current collector with periodic Si O₂ mesh was prepared by screen printing technology.The large specific surface area and porous structure of Si O₂ mesh current collector can balance ion diffusion and current distribution,thus inhibits the growth of Li dendrites.Si O₂ and Li could react to form Li oxide（Li₂O）,which is an important composition of SEI film.Therefore,Si O₂ mesh current collector can form more stable SEI film than that of Cu foil.In addition,the space inside the Si O₂ mesh current collector can alleviate the repeated volume expansion and contraction during the plating/stripping process of Li,thus inhibits the growth of Li dendrites.