Structural Design And Reaction Mechanism Analysis Of A New Lithium Metal Anode

Lithium metal has an ultra-high specific capacity of?3860 m Ah g^-1 and ultra-low redox potential of-3.04V and is considered as one of the most promising anode in the field of advanced batteries.There are many problems in the application of lithium metal anode,such as dendrite,dead lithium,volume expansion of electrode,powder and so on,which have seriously hindered its practical application.In this paper,based on the influence factors of lithium dendrite,considering the volume expansion of electrode,distribution of lithium ion,deposition and stripping of lithium metal and other factors,the design of effective lithium metal anode skeleton to inhibit the growth of lithium dendrite,alleviate the interface side reaction,so as to obtain a stable and efficient lithium metal anode.Carbon nanotubes(CNT)were used to construct lithium composite anode,and the structure of lithium metal anode was investigated.The excellent electrical conductivity and mechanical properties of CNT can be used as the ideal skeleton for lithium metal anode.Ag particles are mixed into the skeleton as the nucleation site of lithium metal,and the influence of the material on the performance of lithium metal anode is investigated.Na Cl particles were introduced to create pores,and 3-dimensional porous lithium metal anode skeleton was constructed.The experimental results show that the introduction of lithiophilic anode skeleton can significantly reduce the nucleation overpotential,and the 3-dimensional lithiophilic porous skeleton constructed by using Na Cl pore-making can greatly improve the electrochemical performance of lithium metal anode,increase the number of cycles of the anode,and stabilize the coulomb efficiency of the battery.The 3-dimensional porous skeleton can not only inhibit the growth of lithium dendrites,but also uniformize the current density and alleviate the volume expansion problem,thus maintaining the stability of lithium anode cycle.In order to further optimize the structure of lithium metal anode,hierarchical porous graphite carbon(HPGC)was used as lithium metal anode framework and atomic layer deposition Mg O was used to modify the interface.The uniform interface with strong Li affinity was obtained,which can effectively regulate the nucleation and deposition behavior of lithium metal.A large amount of Li⁺stored in HPGC micropores can not only regulate the spatial distribution of Li⁺,but also enrich the concentration of Li⁺at the electrode/electrolyte interface,which is conducive to planar lithium metal deposition.In addition,the lithium stripping potential of HPGC is slightly higher than that of lithium metal,which can provide continuous Li⁺for the consumption of lithium on the surface of carbon matrix(the root of dendrite),so as to effectively avoid the shedding of dendrite and the formation of dead lithium.In the application of lithium metal anode,Mg O@HPGC can be used as the internal 3-dimensional porous skeleton of lithium metal anode,significantly improve the cycle stability of lithium metal anode,coulomb efficiency,and cycle number of the anode,so as to obtain excellent performance of lithium metal anode.