Study On The Performance Of A Novel Aluminum-graphite Dual-ion Battery Based On High Concentration Electrolyte

lithium ion batteries(LIBs)with the advantages of high energy density and long cycle life have been successfully commercialized and applied to various modern electronic devices,such as mobile phone,computer,digital camera,aided robot,etc.Whose problems of the environmental pollution caused by the use of lithium-containing transition metal oxide positive electrode and the high cost of batteries caused by the limited reserves and uneven distribution of cobalt and lithium resources make it difficult to meet the requirements in the field of large electronic equipment.However dual ion batteries(DIBs)have attracted much attention recently owing to the advantages,such as low cost,high voltage,and environmental friendliness.Especially,as an optimized cell configuration,the novel aluminum-graphite dual-ion battery(AGDIBs)uses cheap metal aluminum(AI)foil which acts as both collector and anode active material as negative electrode this integration design not only reduces the cost of battery preparation and simplifies the battery structure,but also helps to further improve the energy density of the battery.Nevertheless,the pulverization of Al anode and limited electrolyte concentration restrict the further improvement of performance for DIBs.in this work,we mainly introduce the design idea of aluminum-graphite dua-ion battery based on high concentration electrolyte(referred to as HCE-AGDIBs),the preparation of the battery,the test of electrochemical performance and the study of energy storage mechanism.the reaction mechanism of aluminum negative electrode with lithium-aluminum alloying/dealloying and graphite positive electrode intercalated/deintercalated by anion(FSI-)was systematically studied by exploring the effect of electrolyte concentration on the electrochemical performance of aluminum anode and graphite cathode,the electrode materials after electrochemical reaction were tested and characterized by XRD,SEM,FIB,XPS,Raman characterization.Finally,we have successfully developed an AGDIBs based on a high concentration electrolyte,the formulation of this electrolyte is 5 M LiFSI in 1:1(v/v)ethylene carbonate(EC)and dimethyl carbonate(DMC).The advantage of using this electrolyte are:(1)improved cycling stability of Al anode owing to the formation of a LiF-rich solid-electrolyte interface(SEI)layer;(2)increased intercalation capacity and cycling stability of FSI-at the graphite cathode;(3)improved energy density of Al||graphite based DIB.The Al-graphite DIB with this concentrated electrolyte displays a discharge capacity of 94 mAh g-1 and 96.8%capacity retention after 500 cycles,without any surface treatment and modification of Al anode and graphite cathode.Based on the electrode materials and electrolyte,the energy density of Al-graphite DIB reaches up to 178 Wh kg-1,which is among the best performance of previously reported work.