Research On The Regeneration Of Waste LiNi_xCo_yMn_zO₂ Cathode Materials By Ball Milling Spray Metho

Ternary cathode material(Li Ni _xCo_yMn_zO₂)occupies a place in new energy vehicles and large energy storage applications because of its high ene rgy density,good cycling stability and stable electrochemical platform.With the rapid development of new energy vehicles and the advent of the"carbon p eak"era,the demand and production of lithium-ion batteries are increasing year by year,which makes the number of used batteries also increase dramatically.The ternary cathode material in waste batteries inevitably brings environmental pollution and res ource waste,so there is an urgent need for scientific recycling management of waste ternary cathode m aterial.Facing this problem,this thesis proposes the preparation of new cathode materials by direct regeneration method of ball mill spray,and the main research contents are as follows.For the current common direct regeneration method regenerated terna ry materials have the problems of poor electrochemical performance and complicated process.Taking the waste Li Ni _0.5Co_0.2Mn_0.3O₂ cathode material obtained after pretreatment of waste batteries as the research object,a method of obtaining regenerated catho de material by ball milling,spraying and calcination is proposed.In this method,the waste powder obtained after pretreatment,metal acetate and additives were mixed for wet ball milling,and the resulting suspension was spray dried to prepare the precur sor,and then the regenerated Li Ni _0.5Co_0.2Mn_0.3O₂cathode material was obtained by high temperature calcination.The results showed that the regenerated Li Ni_0.5Co_0.2Mn_0.3O₂ cathode material obtained by regeneration under the conditions of 10h ball milling time,10%additive and 1.2:1lithium replenishment ratio had the best electrochemical performance,with a discharge ratio（0.1 C）capacity of 159.053 m A h g^-1 in the first turn and still maintained a discharge ratio capacity of 145.615 m A h g^-1 after 100 turns（1 C）,with a capacity retention rate of 97.3%,which has a good capacity retention rate.The electrochemical performance of the recycled material pr oduced by this method under these conditions reached the level of commercial materials.At present,the research on the recycling process of waste low-nickel ternary cathode materials has become increasingly mature,but there is little research on the recycling process of waste high-nickel ternary cathode materials.To address this problem,the regeneratio n of waste high nickel ternary materials by the ball mill-spray regeneration method was investigated by taking the waste Li Ni_0.6Co_0.2Mn_0.2O₂ and Li Ni_0.8Co_0.1Mn_0.1O₂ as the research objects.The changes of the samples before and after the regeneration of th e high nickel ternary cathode materials were analyzed by XRD,FT-IR,SEM and HRTEM tests,and the changes of the electrochemical properties of the ternary cathode materials were investigated by electrochemical tests after the nickel content was increased.The results are as follows:the specific discharge capacity（0.1 C）of the regenerated Li Ni_0.6Co_0.2Mn_0.2O₂ cathode material was 169.673 m A h g^-1 in the first cycle,and the specific discharge capacity remained 153.488 m A h g^-1 after 100 cycles（1 C）,with a capacity retention rate of 93.92%and good capacity retention rate.The specific discharge capacity（0.1 C）of the regenerated Li Ni0.8Co0.1Mn0.1O2cathode material was 202.181 m A h g^-1 in the first cycle,and the specific discharge capacity remained 173.980 m A h g^-1 after 100 cycles（1 C）,with a capacity retention rate of 93.40%and a good capacity retention rate.With the increase of nickel content,the capacity of the recycled material also increased,and the phenomenon of particle size inhomogeneity b ecame more obvious,the primary particles became smaller,the porosity became smaller,the individual particles became more dense,and the degree of lithi um-nickel mixing increased,but the spherical shape was well maintained.