Manganese-based Catalysts Recovered From Spent Lithium-ion Batteries And Its Catalytic Activity Performance

In recent years,with the rapid development of new energy vehicles,the recycling of spent ternary power Lithium-ion batteries has drawn wide attention.Manganese is the main metals in the cathode material of spent Lithium-ion batteries,hence it is important to study how to recover the manganese from spent ternary Lithium-ion batteries.In this paper,the technology of recovery of manganese-based catalysts based on spent ternary Lithium-ion batteries were studied.The acid leaching and ammonia leaching methods were used to leach the cathode material of spent ternary lithium-ion batteries.After that,the acid leaching solution and the ammonia leaching residue were prepared and the manganese catalyst was synthesized.This has provided a new recovery method of the cathode metals of spent ternary lithium ion battery.The main conclusions of this paper are as follows:?1?Ammonia leaching method was applied for leaching the cathode active metals,the main component of the obtained ammonia leaching residue is?NH₄?₂Mn?SO₃?₂·H₂O,and the ammonia leaching residue converted into Mn₃O₄ after being calcined at 900^oC for 1h,and the particle diameter D₅₀ is 79.6?m with the smooth surface.The degradation rate of MB is only 11%after 240 min.?2?The ball milling method was used to activate the manganese-based catalyst obtained from the calcination of the ammonia leaching residue. After grinding,the morphology of the manganese catalyst remained unchanged.The grain size became smaller and the lattice strain became larger.The particle size D₅₀ reduced from 79.6?m to 18?m after grinding of 15 min,the specific surface area increased.As a result,the catalytic performance of manganese catalyst was improved,and the MB degradation rate reached to 41.2%after 240 min of catalytic reaction.?3?The leaching treatment of the cathode active material was carried out by acid leaching.The concentration of Mn²⁺in the acid leaching solution was 4824 mg/L.Mn was separated from the acid leaching solution by ammonium persulfate oxidation precipitation method and the manganese-based catalyst was obtained.The experimental conditions were as follows:pH=1,temperature 80 ^oC,reaction time 6h,molar ratio of S₂O₈^2-:Mn²⁺=2,and the manganese-based catalyst obtained under this condition was a mixed crystal phase of?-MnO₂ and ?-MnO₂ with 3%Co and 0.5%Ni.The specific surface area is 118.4 m²/g and the microstructure is spherical with a diameter of about 7?m. The MB degradation rate can reach 80%after 20 min of catalytic reaction.?4?The calcination method was used to activate the manganese-basedcatalysts obtained from the acid leaching solution.The results showed that the crystal morphology changed after calcination,and transformed into?-MnO₂ and?-MnO₂ at 300 ^oC and 500 ^oC,respectively.The specific surface area of manganese-based catalyst decreased after calcination,and the transformation of the crystal form led to the improvement of catalytic performance.The MB degradation rate could reach 100%after 30 min of catalytic reaction.