λ-MnO_(2)的结构与电性能研究

Study on the Structure and Electrochemical Performance ofλ-Manganese Dioxide

采用酸处理LiMn2O4的方法来制备λ-MnO2,并用X-射线衍射(XRD)、扫描电子显微镜(SEM)和恒电流充放电测试等方法对所得λ-MnO2的结构和电性能进行了研究。研究结果表明,所得λ-MnO2具有尖晶石型结构,晶粒细小,形貌较规则,粒径分布均匀;以其为正极组装成Li MnO2电池的放电比容量达到226mAh/g。

Theλ-manganese dioxide (λ-MnO_2) was prepared by acidifying lithium manganese dioxide (LiMn_2O_4), and the crystalline structure, morphology of particles, crystalline size and electrochemical performance ofλ-MnO_2 were investigated by X-ray diffraction, scanning electron microscopy and cycling charge-discharge test. The results showed thatλ-MnO_2 possessed the same spinel-type structure as LiMn_2O_4, and which was characterized by small particles, regular morphology, and uniform distribution of particle size.λ-MnO_2 is very suitable for primary Li?MnO_2 batteries as cathode material, whose first specific discharge capacity reached to 226 mAh?g. But the cycling charge-discharge performance of it is poor, when it was charged to 3.3 V, the specific discharge capacity was 120.4 mAh?g, and after 10 times cycling, the 10th specific discharge capacity was only 50.1 mAh?g.