Compact Processes For Recycling And Re-synthesizing LiNi_0.5Co_0.2Mn_0.3O₂ Cathode From Spent LIBs

As the battery of the largest installed capacity of electric vehicles,the lithium-ion battery of LiNixCoyMnzO2 cathode material is facing the problem of large-scale scrapping.For the direct separation and recovery of valuable metal in this spent cathode material,there are problems such as the long recovery process and low recovery rate,etc.The current research hotspot is to use of valuable metal in spent cathode material re-synthesis new cathode material.In this paper,spent cathode materials were used as research objects,and the leaching study of valuable metal was carried out.The leached solution was concentrated to precipitate and remove the impurity aluminum.The impurity-removed solution regenerated the precursor Ni0.5Co0.2Mn0.3(OH)2 and Li2CO3.the two ratios were calcined to form a new LiNi0.5Co0.2Mn0.3O2 material.Firstly,the leaching study of valuable metal was conducted by exploring different leaching conditions.The optimum acid leaching conditions was determined to be H2SO4 concentration 2.5 mol·L-1,H2O2 3 vol%,solid-liquid ratio 50 g·L-1,temperature 45?.The reaction time was 60 min.Under these conditions,the leaching rates of Li,Ni,Co and Mn were well above 98.5%.In order to reveal the leaching mechanism of the acid leaching process,the avrami equation could be used to correlate experimental data onto the leaching reaction by the kinetic model fitting.The apparent activation energy of the four metal ions is greater than 40 kJ mol-1,and the reaction velocity was controlled by chemical reaction step.In the acid immersion liquid,the concentration of metal ions is low.In order to avoid adding a large amount of new raw materials in the subsequent regeneration process,the acid immersion liquid is concentrated by membrane distillation technology to the total concentration of Ni,Co and Mn ions is close to 2.0 mol·L'1,the basic concentration of co-precipitation is basically reached,and the impurity aluminum concentration is also increased accordingly.For deep removal of impurity aluminum,the pH value of the precipitate in the Me-OH--NH3 system was established by thermodynamic calculation and the aluminum removal verification of the simulated solution.The suitable pH of the actual solution was adjusted to 4.2 with NaOH and NH3.The concentration of aluminum ion is 24.3 mg·L-1,which meets the requirements of coprecipitation impurities and the loss rate of Ni,Co and Mn is lower than 4%.The precursor solution was prepared by hydroxide co-precipitation method to form precursor Ni0.5Co0.2Mn0.3(OH)2.The ICP-OES,XRD and SEM showed that the proportion of transition metal in transition precursor and total metal and The impurity ion content and particle size are in accordance with the manufacturer's specifications.The diffraction peak of the material is sharp,the crystallinity is high,and the morphology shows good spherical particles.The filtrate after coprecipitation was concentrated and removed to form Li2CO3.The element content analysis and XRD showed that the purity of Li2CO3 was as high as 99.3%,which is basically meet the requirements of Li2CO3-0 level.The regenerated precursor Ni0.5Co0.2Mn0.3(OH)2 and Li2CO3 were calcined to form a LiNio.5Coo.2Mno.3O2 ternary material.SEM-EDS,XRD and XPS measurements show that the material maintains a uniform spheroidal shape with high crystallinity and small cation mixing degree.The distribution of each metal element is uniform,Ni is+2 and+3,and Co is mainly+3 price,Mn is+4 price.The ternary material was prepared into a button cell for electrochemical testing.The recycled material exhibited excellent cycle performance and rate performance.The capacity retention rate was as high as 95.21%after 100 cycles at 1.0 C rate,and the weekly coulombic efficiency was 99%,the average discharge capacity is 137.33 mAh·g-1 at 3.0 C,and the initial discharge capacities are 162.3 and 144.3 mAh· g-1 at 0.1 C and 1.0 C,respectively.The tests show that the regenerated LiNi0.5Co0.2Mn0.3O2 can meet the commercial requirements for the performance of ternary materials.The regenerated precursor Ni0 5Co0.2Mn0.3(OH)2 and Li2CO3 were calcined to form a LiNi0.5Co0.2Mn0.3O2 ternary material.SEM-EDS,XRD and XPS measurements is shown that the material maintains a uniform spheroidal shape with high crystallinity and small cation mixing degree.The distribution of each metal element is uniform.Ni is+2 and+3,and Co is mainly+3 prices.Mn is+4 price.The ternary material was ready into a button cell for electrochemical testing.The recycled material exhibited excellent cycle performance and rate performance.The capacity retention rate was as high as 95.21%after 100 cycles at 1.0 C rate,and the weekly economic efficiency was 99.Above 100%,the average discharge capacity is 137.33 mAh·g-1 at 3.0C,and the initial discharge capacities are 162.3?144.3 mAh·g-1 at 0.1 C and 1.0 C,respectively.The tests show that the regenerated LiNi0.5Co0.2Mn0.3O2 can meet the commercial requirements for the performance of ternary materials...