锂离子电池正极材料LiMn_2O_4的合成及其电化学性能研究

Studies on Synthesis of Cathode Material LiMn_2O_4 for Lithium-Ion Batteries and It's Electrochemical

以Ｌｉ２ＣＯ３为Ｌｉ源，化学ＭｎＯ２（ＣＭＤ）和电化学ＭｎＯ２（ＥＭＤ）为Ｍｎ源，以乙醇水混合物为分散介质，采用固相反应法合成了可充电锂离子电池正极材料ＬｉＭｎ２Ｏ４尖晶石，并采用ＸＲＤ，ＢＥＴ，ＴＥＭ和电化学测试对材料进行了表征．结果表明，７５０℃制备的样品呈良好的尖晶石结构，比表面积分别为４．８ｍ２／ｇ和 ２．８ｍ２／ｇ，产物的分布均匀，平均粒径为 ２００ｎｍ．在０．４ｍＡ／ｃｍ２（０．２～０．５Ｃ）和３．０～４．３５Ｖ条件下恒流充放电，其首次放电容量大于１１０ｍＡｈ／ｇ，效率大于９０％，并具有较好的循环和可逆性。考察了反应温度对材料比表面积的影响。

The cathode material LiMn2O4 for lithium-ion rechargeable batteries were synthesized by the dispersion of ethanol-water mixed media using lithium carbonate (AR) as lithium source, chemical manganese dioxide (CMD) and electrochemical manganese dioxide (EMD) as manganese source in combination with the solid state reaction, and characterized by XRD,BET,TEM and electrochemical testing. The results revealed that the sample prepared at 750℃ exhibited good single-phase spinel LiMn2O4 structure, the specific surface area was 4. 8m2/g (prepared with CMD) and 2. 8m2/g (prepared with EMD) respectively. The sample has a uniform distribution and an approximate 200nm of average diameter. Under the condition of 0. 4mA/cm2 (0. 2～0. 5C) and 3. 0～4. 35V, charge and discharge is carried out galvanostatically,the samples has the first discharge capacity of more than 110mAh/g, and the D/C ratio of more than 90% and better cyclability. The effects of reaction temperature on the specific surface areas were investigated.