Dendrite-suppressed Lithium Plating From Anode Structure Design In Lithium Metal Batteries

Lithium with ultra-high theoretical capacity(3840mAh g-1),the lower density(0.534g cm-3)and the lowest potential(-3.04V),are considered as an ideal material of anode material for lithium batteries.In the meantime,there are still some defects in Lithium batteries,such as:low coulometric efficiency,great capacity attenuation,and short cycle life,which brings a great challenge to their popularity.In terms of electrochemistry,these problems are caused by dendritic growth when Lithium batteries are in the process of electroplating.The growth of dendrites is related to the instability and symmetry of solid electrolyte interface,unfixed electric field of the growth matrix of lithium,and Inhomogeneity flux of lithium ion.This paper starts with the structure design of anode material for lithium batteries,sparing no effort to limit the growth of lithium dendrites by solving the uneven deposition of lithium batteries in order to increase their cycle life and coulometric efficiency.First of all,we designed a three-dimensional conductive network structure,being based on a melamine form where gold is loaded on as a nuclear growth point.As a growth point for lithium nucleation,gold has a very low nucleation barrier;meanwhile,as a good conductor,gold can also effectively homogenize the electric field strength of the growth matrix of lithium.The three-dimensional network structure of melamine form can effectively equalize flux of lithium ion in dielectrics and increase the surface area to reduce the local current density;in addition,the three-dimensional structure is conducive to limiting the volumetric expansion of lithium.Based on the above advantages,the anode material for lithium batteries,Regarding melamine form-gold as carrier,exhibit a cycle life of more than 350 cycles and a coulombic efficiency of about 99%at a current density of 1 mA cm-2,and it maintains more than 100 cycles at 5mA cm-2.With the advantages of simple preparation procedure,low density and good flexibility,this kind of structure significantly improves batteries performance and has the potential to be used in wearable devices and other fields.Moreover,we have produced a layer of lithium amide on the lithium surface as an artificial SEI film.Compared to the original SEI film,the artificial SEI film is more even,and it is not easily broken during the electroplating,which not only ensures the unifom deposition of lithium,but also physically blocks the growth of dendrites.This lithium anode treated with ammonia gas maintains a cycle life of over 300 cycles at a current density of 1mA cm-2,while having good full cell performance.In conclusion,by designing the structure of anode material for lithium batteries,we have effectively suppressed the growth of dendrites when lithium batteries are in the process of electroplating.In this way,we achieve excellent electrochemical performance as well.This idea can be further extend to a variety of composite structures,so that lithium batteries will soon serve our daily lives.