Preparation Of Lithium Manganate And The Recovery Of Cathode Material From Spent Lithium-ion Battery

Nanostructured lithium manganates have excellent electrochemical performance because of their large space for lithium ion intercalation and short path for lithium ions to diffuse through the solid phase. In the charge and discharge processes, the volume and porosity of lithium manganates increase with lithium ion intercalation and deintercalation. By leaching lithium ions out from lithium manganates via the chemical route, excellent MnO2 catalyst can be made. This provides a new method for the recovery of cathode material from spent lithium-ion battery.In our previous research work, monoclinic Li2MnO3 nanorods and orthorhombic LiMnO2 nanorods were prepared based on the nanostructured precursorγ-MnOOH by hydrothermal oxidation and reduction method, respectively. In this paper, we go a further step to investigate the electrochemical performance of the as-prepared lithium manganese oxides. The results show that the first discharge capacities based on the Li-Li2MnO3 batteries and the Li-LiMnO2 batteries are 133 mAh·g-1 and 170 mAh·g-1, respectively. After 50 cycles, their capacity retention is 60 % and 59 %, respectively.With prepared monoclinic Li2MnO3 and cubic LiMn2O4 as precursors, manganese oxides were obtained by selective chemical leaching of lithium ion in autoclave. X-ray powder diffraction (XRD) and transmission electron microscopy (TEM) were used to characterize the obtained manganese oxides. The results show that the samples areα-MnO2 nanorods andβ-MnO2 nanorods, respectively. They were employed as catalysts for the decoloration of methylene blue (MB). Experiments indicate thatα-MnO2 andβ-MnO2 exhibit higher catalytic efficiency than commercial MnO2. And the decoloration rate of MB forα-MnO2 andβ-MnO2 catalysts are as high as 86% and 98%, respectively, while for the commercial MnO2 that is only 51%.In addition, manganese oxides were synthesized from the spent LiMn2O4 electrode materials. The preparedλ-MnO2 catalyst by in-situ phase transformation was found to be an effective catalyst for the synthesis of iso-amyl acetate from acetic acid and iso-amyl alcohol (high yield 94.62%). Through the selective chemical leaching of lithium ion in autoclave, different types of MnO2 were prepared. The prepared MnO2 samples were also used as catalysts for esterification reaction.