Li-birnessite型层状二氧化锰的合成及电化学性能

Preparation and Electrochemical Properties of Layered Manganese Oxide(Li-birnessite Type)

采用O2氧化法在碱性条件下氧化Mn2+,制备Li-birnessite型层状MnO2.X射线衍射、扫描电子显微镜、BET、热重等技术表征MnO2样品的性能.以放充电法测试Li-birnessite正极材料性能.结果表明,Li-birnessite结晶良好,层间距约为0.70 nm,呈球状或类球状.以Li-birnessite为正极材料的扣式电池在0.2 C(40 mA/g)条件下放电时容量高达203 mAh/g,且具有良好的倍率性能.

Layered Li-birnessite was prepared by means of oxidizing Mn^2 ＋ with O2 gas in alkaline media. The as-prepared sample was characterized by scanning electron microscopy （SEM）, X-ray diffraction （XRD）, BET and thermogravimetric/diffenential thermal analysis （TG/DTA） techniques. The electrochemical properties of the material were also investigated. The results show that such a Li-birnessite consists of well-crystallized spherical particles with an interlayer distance of 0.70 nm. The Li-birnessite delivered a high discharge capacity of 203 mAh/g at a rate of 0.2 C （40 mA/g）, and had good rate capability as well.