The Resynthesis And Reuse From Materials Of Spent Lithium Ion Batteries Of Phosphate And Mixture

The widespread application of Lithium-ion batteries(LIBs)in consumer electronics and electric vehicles drive an rapidly growing command of metallic resources such as lithium and cobalt.The recycling of LIBs will be of necessity for not only lessening the consumption of energy,but also relieving the shortage of rare resources and eliminating the pollution of hazardous components.Compared with the recycling research of LiCo O2 batteries,reseaches on the recovery of the phosphate cathode materials and hybrid lithium ion battery are very limited.Therefore,in this paper we focused on the recovery of spent phosphate lithium iron batteries with LiFe PO4 and Li3V2(PO4)3 as cathode materials and various types of hybrid lithiumion batteries.The separation mechanism of the active materials from the collector,was investigated and the separation methods for different types of LIBs.Also set up was we optimized the recycling technology of metal ions,studied the physical and chemical properties of recycled products using synchrotron radiation X-ray absorption and scanning electron microscopy(SEM)and fulfilled the recycle of waste products.For the refabrication of electrode materials,the physical and electrochemical properties were examined.In this paper,the separation method of active materials from the collectors is investigated.For spent LIBs with phosphate cathode materials,the separation of cathode materials and aluminum foil was achieved by heating treatment of 600°C for 1 h,which was conducted to remove coating binder,surface active substances and carbon.At the same time,the oxidization from Fe2+ to Fe3+ favors the subsequent recovery of FePO4.For the overall recycling of hybrid lithium ion batteries,aluminum foil was dissolved by alkali solution to realize the separation from active materials.The best reaction conditions were as follows: the concentration of sodium hydroxide was 30g?L-1,the temperature is 50 ? and the time was 1 h.For the spent cathode electrodes,0.5mol?L-1 sodium hydroxide solution was used to dissolve trace amounts of aluminum foil,which caused the interface defects.Under ultrasonic auxiliary,the active materials and the collectors were separated finally,and the separation mechanism of ultrasonic assisted was discussed in detailed.The recovery method of the metal ion in spent lithium ion battery was studied.For spent LiFe PO4 LIBs,the active substances isolated from collectors was dissolved in sulfuric acid for leaching of iron and lithium.The mixed powder was then dissolved in 2.5 mol?L-1 sulfuric acid with the L/S ratio of 10 m L?g-1,temperature at 60 °C and time of 4 h.As a result,98 % iron and 97 % lithium were leached from the mixed powder.The p H value to 2 was adjusted by adding ammonia to cause the precipitation of FePO4?2H2O.We discussed the influence of surfactant on particle size and surface morphology of recycled products.The results show that adding nonionic surfactant leads to smaller particle size and homogeneous particle size distribution.Synchrotron radiation X-ray absorption results show that Fe elements own the same local area structure in both the recycled products by adding nonionic surfactant commercialization and the commercial iron phosphate.Li,Fe and V were reclaimed together and prepared as x LiFe PO4-y Li3V2(PO4)3 materials from spent LIBs with LiFe PO4 and Li3V2(PO4)3 as cathode materials,due to their similar characteristics and preparation method.After the active materials were roasted to separate from aluminum foil collector and adjusted the mole ratio of Li,Fe,V and P,the x LiFe PO4-y Li3V2(PO4)3(x:y = 5:1,7:1,9:1)composite electrode materials with different proportions were synthesized by ball-milling and calcination.The result plays a guiding role in finding new recycling process routes of lithium vanadium phosphate battery.Metal ions of active materials from mixed spent lithium ion batteries including LiCo O2,LiMn2O4,LiNix Coy Mnz O2 and LiFe PO4 were leached by the mixture of sulfuric acid and hydrogen peroxide after the separation from the collectors.In order to guarantee the purity of the recovered product,we explored the impurity removal process by suchas using precipitation to remove iron,copper extraction agent to remove copper ion and phosphate ester extraction agent to further remove iron,aluminum,copper and other impurities.The coprecipitation of nickel,cobalt and manganese by sodium hydroxide was directly prepared as the precursor of Li-Ni-CoMn batteries to avoidi the separation and purification of metal ions.The reuse of recovered products was studied.Under the optimized conditions,the recycled FePO4 was used as the iron source and phosphorus source;Li2CO3 was used as lithium source,then LiFe PO4/C was synthesized by a carbon-thermal reduction method.The XAFS was applied to compare the properties of the reprepared LiFePO4/C and the commercialized one.The results illustrate that the reprepared LiFe PO4/C reclaimed by adding non-ionic surfactant is most closely with the commercial products.The optimized LiFe PO4/C cathode material was then assembled as a half cell.After the electrochemical performance test,the as-prepared LiFe PO4/C shows the electrochemical performance with the first discharge capacity of 155.4 m Ah?g-1,which is comparable to that of commercial one of 153.3 m Ah?g-1.The re-prepared x LiFePO4-y Li3V2(PO4)3 composite materials with recycledLiFe PO4 and Li3V2(PO4)3 products showed comparable electrochemical performance with that synthesized using pure chemical reagents,which solves the harsh situation of spent Li3V2(PO4)3 batteries recycling and explores a new way for the recycling of spent lithium ion battery.Li(Ni1/3Co1/3Mn1/3)O2 cathode material was prepared by solid phase method with recycled products from spent hybrid lithium ion batteries as the precursor and lithium carbonate as fresh raw material.After assembled half cell,the battery performed well with the first discharge capacity of 148.8 m Ah?g-1 and the cycle efficiency of 97% after 100 cycles.By comparison,a fresh-synthesized sample with the same composition is also prepared using the commercial raw materials via the same method.This dissertation put forward the parctical technology for the recycling of spent LIBs including LiFe PO4,Li3V2(PO4)3 and hybrid cathode materials.