关键词: 锂离子电池, 锂锰氧化物, 钡镁锰矿, 钠水锰矿, 水羟锰矿

Abstract: In this paper, Todorokite manganese oxides containing Li + with large tunnel structure(sample M5) have been synthesized by hydrothermal methods from natural manganese oxide nano fiber (sample M4). The structure and composition of the samples were characterized and analyzed by XRD, ICP, TGA and DTA. Its electrochemical behavior as a cathode materials for rechargeable lithium ion insertion were studied by galvanostatic charge/discharge measurements. XRD results show that the sample M4 is mainly composed of Birnessite and Vernadite structure. Although the sample M4 shows a high initial capacity of approximately 150 mAh/g, its performances decrease gradually over 30 cycles. It is found that the materials have highly reversible charge/discharge cycling performances after being converted into Todorokite lithium manganese oxide(sample M5). This sample exhibit a single reduction step centered at Ca. 2.8 V and its discharge capacity maintains about 110 mAh/g after 180 cycles at current density of 0.8 mA/cm 2. The novel lithium manganese oxide with a large tunnel structure can be used as 3V cathode material of lithium ion batteries.

Key words: Lithium ion batteries, Lithium manganese oxides, Todorokite, Birnessite