Abstract:

λ-MnO₂ nanoparticles and β-MnO₂ nanorods were successfully prepared from spent LiMn₂O₄ cathode materials by controlling appropriate leaching conditions in this study. Their electrochemical properties were investigated as electrode materials for primary cells and supercapacitors. The composition, morphology and electrochemical properties of the obtained samples were characterized by X-ray powder diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), constant current charge-discharge and cyclic voltammetry measurements. The results indicated that λ-MnO₂ nanoparticles could be prepared at ambient temperature and pressure, with 0.5 mol·L^-1 H₂SO₄ leaching the spent LiMn₂O₄ for 3 h, and β-MnO₂ nanorods could be synthesized under hydrothermal conditions of 140℃, with 2 mol·L^-1 H₂SO₄ leaching the spent LiMn₂O₄ for 24 h. The λ-MnO₂ and β-MnO₂ samples delivered discharge capacities of 142 mA·h·g^-1

摘要：

以废旧锂离子电池LiMn₂O₄正极材料为原料，通过控制酸浸条件分别制备出λ-MnO₂纳米粒子和β-MnO₂纳米棒，研究作为一次电池电极材料和超级电容器电极材料的相关电化学性能。利用X射线粉末衍射（XRD）、扫描电子显微镜（SEM）、透射电子显微镜（TEM）和恒电流充放电、循环伏安等测试手段对样品成分、形貌和电化学性能进行分析表征。实验表明：在常温常压下，采用0.5 mol·L^-1的H₂SO₄酸浸3 h可制备出λ-MnO₂纳米颗粒；而于