Phosphorus-based Anodes For Lithium/sodium Ion Batteries Prepared By Ball Milling Method

Lithium ion batteries?LIBs?have the advantages of high energy density,long cycling life and safety,etc.,and have been widely used in mobile electronic devices and electric vehicles.With the development of these devices,people put higher request forward the energy density and cycling life of LIBs.Thus,it is urgent needs to develop the next generation electrode materials to improve the overall performance of LIBs.Besides,with widely use of these devices,the lithium resources have been excessive consumed,and the lithium prices continue rising.Therefore,the sodium ion batteries?SIBs?with the advantages of abundant resources and low prices have attracted more and more attentions,while the commercial use of SIBs also needs to develop electrode materials with high performance.As one of the key components of LIBs and SIBs,the performances of anode materials will significantly influence the overall battery performance.Red phosphorus?RP?has attracted more and more researcher's attentions due to its high theoretical lithium/sodium storage capacities.However,the poor electrical conductivity and huge volume changes during lithium/sodium storage processes leads to poor reversible lithium/sodium storage capacities.Based on the problems of RP anodes in LIBs and SIBs,we prepared phosphours-based materials by ball milling method to improve the reversibility of P component during lithium/sodium storage processes,and the effect of metallic elements and preparation processes on the lithium/sodium storage performance of the phosphorus-based materials were also discussed.Firstly,used Ag and RP powder as raw materials,and prepared silver phosphide?AgP₂?through high energy shake ball milling.Compare with pure P electrode,the initial Coulombic efficiency of the AgP₂ electrode in lithium ion batteries was significantly improved.In order to further improve the cyclic stability of materials,we used carbon black?CB?as carbon resource,and prepared AgP₂/amorphous carbon?a-C?composite through planetary milling.Transmission electron microscope?TEM?measurements indicated the AgP₂ nanocrystallines were uniformly distributed in amorphous carbon matrix in the AgP₂/a-C composite.Due to the amorphous carbon matrix not only improve the electric conductivity of material,but also alleviate the volume expansion of active AgP₂ particles,the cyclic stability of AgP₂/a-C electrode in LIBs was obviously better than AgP₂ electrode.Further X-ray diffraction?XRD?and TEM measurements indicated the Ag and P components in the AgP₂/a-C composite own synergistic effect during lithium storage processes,the Li₃P phase formed by lithiation of P can inhibit Ag grain coarsening during cycling,while the in-situ formed Ag fine grains can activate of P component.Secondly,to obtained anode materieals with excellent cycling performace for both LIBs and SIBs,we used Zn,Ge and RP powders as raw materials,and prepared zinc-germanium phosphide?ZnGeP₂?through high energy shake ball milling.And in order to explore the different carbon resources on the influence of the lithium/sodium storage performaces of the composites,we have prepared ZnGeP₂/a-C composite and ZnGeP₂/graphene nanosheets?GNs?composite through planetary milling and plasma-assisted milling,respectively.Scanning electron microscope?SEM?and TEM measurements indicated the GNs were unformly around ZnGeP₂ particles in the ZnGeP₂/GNs composite.Compare with the amorphous cabon in the ZnGeP₂/a-C composite,the GNs with large specific surface area can provide better linking and more buffer space for the active ZnGeP₂ particles,thus ensure the good contact between active materials and current collector.As a result,the cycling performance of ZnGeP₂/GNs electrode in LIBs and SIBs was better than ZnGeP₂/a-C electrode.Finally,we have prepared the antimony nanocrystalline/phosphorus-carbon?Sb/P-C?composite by simple one-step plasma-assisted milling.In this material,the Sb nanocrystallines are uniformly distributed in amorphous P-C matrix,the P and C components are connected by P-C bonds.The electrochemical performace measurements found,the Sb/P-C composite not only have high capacity,but also owns excellent cycling stability in both LIBs and SIBs.The excellent lithium/sodium storage performace of this material was attributed to its unique structure,the well-dispersed Sb nanoparticles can activate the P component,and the P-C bonds formed during plasma-assisted milling process will strengthed the structural resistance against the volume stress during electrochemical reaction processes.