Study On The Preparation Of High Nickel Ternary Cathode Material By Spray Drying And Its Electrochemical Performance

With the increasing energy demand of human society,the pollution problem brought by the traditional energy system is increasingly serious.Lithium ion batteries are widely used in new energy vehicles due to their advantages of small self-discharge,high safety and long life.At present,the cathode material of lithium ion battery basically adopts graphite,whose specific capacity is much higher than the existing anode materials such as lithium cobalt acid,lithium iron phosphate and lithium manganese acid.Therefore,the nickel-rich ternary materials with higher specific capacity than the traditional cathode materials have attracted the attention of many researchers.However,the traditional coprecipitation process is complicated,the reaction conditions are harsh and the need to use a large number of acid and base solutions easily lead to environmental pollution.Spray drying is a simple,efficient and environmentally friendly synthetic method,which has been applied in many fields such as medicine and materials.Therefore,this paper successfully synthesized high nickel ternary material(Li Ni_0.8Co_0.1Mn_0.1O₂)by simple and efficient spray drying method,and explored and optimized its process steps and parameters.The physical and electrochemical properties of the synthesized materials were characterized and evaluated,and Suggestions and strategies for the practical application of high nickel ternary materials were proposed.Firstly,the transition metal acetate was used as raw material to prepare the spray solution and the precursors without lithium were prepared by spray drying.The precursor was thermally decomposed under oxygen conditions to obtain transition metal oxides,which were then mixed with Li₂CO₃ and calcined to prepare Li Ni_0.8Co_0.1Mn_0.1O₂.In this process,we investigated the influence of different concentrations of spray solution on the electrochemical properties of the final product.The structure and morphology of the material were characterized by TG,XRD,SEM and TEM.The electrochemical properties were tested.The results showed that the sample 0.4M-NCM811 had the best electrochemical performance,with a reversible capacity of 199.7m Ah g^-1 at current density of 0.1C(1C=180m A g^-1)?The process is then further simplified.A solution containing both lithium source and transition metal acetate was obtained by using citric acid as complexing agent.Thus,the step of mixing with lithium source is eliminated,and the precursor obtained by spray drying can be directly calcined to prepare Li Ni_0.8Co_0.1Mn_0.1O₂.At the same time,we investigated the influence of different sintering time on the electrochemical properties of the final product.By TG,XRD,SEM and other physical characterization,the structure,morphology and physical properties of the material were analyzed.The electrochemical test results showed that the samples with sintering time of 8h had the best electrochemical performance,and the reversible capacity was 207.3m Ah g^-1 at0.1C.At last,the materials prepared by the above two methods were combined with different commercial electrolytes to assemble the semi-battery,and the effects of different electrolytes on electrochemical properties were compared.