Exploring Lithium-rich Antiperovskites Materials For Safe And High-energy-density Lithium Batteries

Lithium-ion batteries have been widely used in consumer electronics,electric vehicles,large-scale energy storage and many other areas.With the growing needs for energy storage,people put forward more requirements for the safety and high-energy density of lithium batteries.Lithium sulfur and lithium-air battery systems based on lithium metal anode,have the potential to be the next generation lithium batteries.Lithium-sulfur batteries have a theoretical capacity of up to 1167 m Ah g-1 and a theoretical energy density of up to 2600 Wh kg-1.At present,the development of lithium sulfur battery is mainly inhibited with two problems: one is safety hazard caused by lithium dendrite growth,another is the existence of poor conductivity,polysulfide shuttlethrough and huge volume variation of positive sulfide greatly reduces the actual capacity and cycling performance of lithium sulfur batteries.Considering that some inorganic solid electrolytes have the characteristics of high ionic conductivity,low electron conductivity and uniform density,it is expected that they can improve the performance of lithium sulfur batteries in the above two aspects.It is considered to be an effective way to modify a solid electrolyte membrane on the negative surface of lithium metal by different means to provide a good path for the interfacial charge transfer and act as a barrier against polysulfide.Therefore,the choice of the appropriate solid electrolyte and the appropriate film-forming process are the key point.In this paper,Li-RAP solid electrolyte with excellent properties represented by Li3 OCl was synthesized.It was modified to the surface of lithium metal by means of molten-coating and electrochemical deposition as an artificial SEI film protecting lithium metal anode.The lithium metal anode obtained by this method got great improved in columbic efficiency,it was showed that the Li|Cu half-cell could cycle for over 1500 cycles at an average CE of 99.5%,and the Li-S battery using this anode could still have a capacity retention rate of 70% after 3000 cycles at the current density of 11.5m A cm-2.Furthermore,the author explored the structure change and specific dendrites suppressing mechanism of the Li-RAP artificial SEI during the electrochemical cycle of lithium sulfur batteries by different characterization methods such as SEM,XPS in-situ XRD and in-situ optical microscope observation of electrochemical cycling.It was pointed out that high ionic conductivity is the crucial reason for Li-RAP to protect lithium metal anode from dendrites.Finally,the author made some outlooks into future experiments and development.