Study On The Regeneration Of Lithium Cobalt Oxide From Waste Lithium Cobalt Oxide Cathode Material By Suspension Electrolysis

The acceleration of the upgrading of electronic products has led to a large number of generation of waste lithium-ion batteries.The reasonable dispose of them is an inevitable requirement of avoiding environmental pollution,promoting sustainable use of resources,and alleviating the shortage of strategic resources of lithium and cobalt in China.At present,most technologies of recycling waste lithium-ion battery have problems such as long processes,high costs,and serious secondary pollution.There is an urgent need for an efficient,environmentally friendly,and low-cost method to promote the recycling of waste lithium-ion batteries.To this end,this paper proposes a tecnology applying suspension electrolysis for the recovery of waste lithium cobalt oxide cathode materials in order to achieve the leaching,purification and regeneration of waste lithium cobalt oxide in one step.The main conclusions are as follows:The results of the ammonium bicarbonate suspension electrolytic reaction system show that under this system,the reaction efficiency of lithium cobalt oxide is low,the leaching rate of cobalt is basically below 2%,the leaching rate of lithium is below 9%,and lithium cobalt oxide cannot be synthezied in the cathode area.The results of the ammonium bicarbonate-ammonium sulfite suspension electrolysis reaction system show that the system can achieve anodic leaching and cathodic deposition of lithium cobalt oxide in one step,and obtain the optimal parameters,which are 2.5 mol/L ammonia bicarbonate concentration,3.5 A current,0.7 mol/L ammonium sulfite concentration,90 min,60 °C,4 g/L solid-liquid ratio,and 2.5 g sodium fluoride.Under this condition,the leaching rate of lithium reaches 95.31%,the leaching rate of cobalt can reach 88.57%,and the recovery rate of lithium cobaltate reaches 75.2%.At the same time,X-ray energy spectrum analysis shows that lithium cobaltate regenerated at the cathode contains sulfur element,which has a larger specific surface area and a loose surface.The results of the suspension electrolysis experiments on waste lithium cobalt oxide batteries show that under the optimal conditions,the lithium leaching rates of the crushed powders of the waste battery,the waste cathode flakes,and the waste cathode material are 32.78%,71.8%,and 75.32%,respectively.The leaching rates of coblat were 26.34%,55.42% and 61.95%,respectively.And the recovery rates of lithium cobalt oxide were 31%,51.5% and 51.8%,respectively.The results show that the fewer impurities in the raw materials,the higher efficient regeneration rate of lithium cobalt oxide.At the same time,the analysis of inductively coupled plasma spectrometer showed that the above three kinds of waste materials and their corresponding cathode deposition products all contain impurities,such as Al,Cu,Fe,Ni,Mn.According to these results,the content of impurities in the cathode deposit products are significantly lower than that in their corresponding raw materials.