Recovery And Secondary Utilization Of High Nickel Lithium Ion Cathode Battery

Lithium-ion batteries are considered to be one of the most promising chemical energy sources,with ternary lithium-ion batteries attracting attention for their high specific capacity,high operating voltage and good cycling performance,and have been widely used in various electronic products and even in new energy electric vehicles.Due to the limited lifespan of lithium-ion batteries,a large number of spent lithium-ion batteries will be generated by electronic products and the replacement of battery power supplies.The recycling of spent lithium-ion batteries has a dual significance of resource utilization as well as environmental protection,and has been studied by a large number of researchers to make them recyclable.In this paper,LiNi_0.5Co_0.2Mn_0.3O₂（NCM523）,a high nickel lithium-ion cathode material,was selected as the research object,and acid leaching treatment and regeneration studies were conducted on this material.Acid leaching of spent ternary high-nickel lithium ion electrode materials by H₂SO₄and Na HSO₃,and optimization of acid leaching experimental parameters by control variable method.The optimal process parameters for the leaching of spent NCM523cathode materials with H₂SO₄ and Na HSO₃ were obtained as follows:the concentration of H₂SO₄ was 1.0 mol/L,the concentration of Na HSO₃ was 0.1 mol/L,the solid-liquid ratio was 20 g/L,the leaching temperature was 70°C and the leaching time was 90 min.The Ni-P powder was prepared from NCM523 acid leaching solution by liquid-phase reduction method.The process parameters（solution p H,reaction temperature,reaction time,amount of reducing agent and nickel ion concentration）for recovering and preparing Ni-P powder were optimized.The morphology and structure of the products were characterised by SEM and XRD,and the irregular block Ni-P powder was formed.The NCM523 acid extract was used as raw material to prepare ternary precursor by coprecipitation with three kinds of precipitants.The technological parameters of coprecipitation process（solution p H,reaction temperature,reaction time,dosage of precipitant）were optimized.The precursors were pre-fired and calcined with Na₂CO₃ to synthesize Na Ni_0.5Co_0.2Mn_0.3O₂ cathode material.The morphology and structure of the materials were analysed by SEM and XRD,and the electrochemical properties of the materials were investigated by charge/discharge performance tests and electrochemical impedance spectroscopy tests to compare the performance of the materials synthesised with different precipitants.The results showed that the sodium ion battery prepared with sodium hydroxide as the precipitant had a better morphology and structure,and the first discharge specific capacity was 81.09 m Ah/g.After 20 charge/discharge cycles,the capacity retention rate was 63.15%,which was better than the materials prepared with the other two precipitants.