چكيده به لاتين
The recycling of industrial wastes is a serious concern of today's societies due to the environmental requirements as well as the lack of non-renewable resources. Lithium-ion batteries have recently been considered as batteries with technological importance in many applications owing to their unique features; the recycling of these electronic devices is also of considerable importance. In this study, recycling of lithium-ion (LiNixMnyCozO2) as well as zinc-carbon, manganese-containing batteries has been performed to recover lithium and manganese, respectively, and then a cathode material (LiMn2O4) was synthesized using these recycled values. In the case of Zn-C batteries, the valuable components including anode, cathode and electrolyte were first neutral-leached with distilled water to remove electrolyte (zinc chloride) and then a complete leaching stage was carried out by a solution of 2M sulfuric acid in the presence of reducing agents (oxalic acid and glucose) at 70°C for 120 minutes. Eventually, manganese was precipitated from acidic leaching solution as spherical MnO2 particles having amorphous structure and sub-micron sizes. In the case of lithium-ion batteries, after discharging and disassembling, the attaching aluminum foil was selectively dissolved from the cathode by leaching in 2.5M sodium hydroxide solution in ambient temperature for 2 hours. In the next step, the lithium of the solid residue was separated from other elements (Ni, Co, and Mn) by a selective leaching method with oxalic acid at 70°C for 2 hours. Then, crystalline lithium oxalate (C2HLiO4.H2O) was obtained by evaporation of the resulting solution. Finally, the recovered materials from the used batteries were utilized to synthesize LiMn2O4 spinel cathode and the effects of parameters like type of raw materials recovered from recycled batteries, synthesis temperature, synthesis time and mechanical activation were investigated. Certain parameters were studied to predict the electrochemical performance of the synthesized cathode using X-ray diffraction patterns. According to the results, the electrochemical performance of the spinel cathode synthesized at 850°C for 10 hours was predicted to be the best. In order to evaluate the electrochemical performance of the synthesized cathode in practice, the cathode was subjected to a battery charge/discharge test in the range of 2.5-4.5 volts. The initial specific capacity of the predicted sample was obtained as 118.3mAh/g.
