锂离子电池片状四氧化三钴负极的合成及改性  

Synthesis and Modification of a Lamellar Co_3O_4 Anode for Lithium-Ion Batteries

作　　者：黄国勇[1] 徐盛明[1,2] 李林艳[1] 王学军[1] 路莎莎[1] 

机构地区：[1]清华大学核能与新能源技术研究院,北京100084 [2]清华大学,精细陶瓷北京市重点实验室,北京100084

出　　处：《物理化学学报》2014年第6期1121-1126,共6页Acta Physico-Chimica Sinica

基　　金：国家自然科学基金(51274130)资助项目~~

摘　　要：采用液相沉淀法结合低温固相热解法合成了锂离子电池片状Co3O4负极.通过X射线粉体衍射(XRD)、Brunauer-Emmett-Teller(BET)比表面积分析、扫描电子显微镜(SEM)及恒电流充放电等表征手段,发现该Co3O4为立方相,结晶完整且无杂质,由直径为1.5-3.0μm、厚度约为100-300 nm的不规则片状颗粒组成,比表面积约为30.5 m2·g-1;其比容量高且容量保持率好,在0.1C倍率下,首次放电容量高达1444.5 mAh·g-1,50次循环后充电容量仍大于1100.0 mAh·g-1;但在高倍率(1C)下,50次循环后充电容量保持率仅为75.3%,倍率性能一般.故采用碳纳米管(CNTs)掺杂改性,结果表明:在1C倍率下,70次循环后复合材料充电容量保持率为96.3%;在2C倍率下,50次循环后充电容量保持率仍高达97.0%,倍率性能显著提升.For advanced performance lithium-ion batteries （LIBs） various novel electrode materials with high energy density have been extensively investigated. Cobaltosic oxide （Co3O4）, commonly used as an anode in LIBs, has attracted much interest because of its high theoretical specific capacity （890 mAh·g-1）, high tap density, and stable chemical properties. However, its practical use has been hindered because of its low electronic conductivity and poor rate capability. To address these problems, we investigated a liquid phase precipitation method fol owed by thermal treatment and obtained a unique lamel ar Co3O4 powder. Its X-ray diffraction （XRD） diffraction peaks match the standard pattern for cubic phase Co3O4 with good crystal inity. We found that the Co3O4 powder consists of many irregular sheets （1.5-3.0 μm in diameter, 100-300 nm in thickness） with numerous poles by scanning electron microscopy （SEM）. Additional y, the surface area was about 30.5 m2·g-1, and this was calculated from BET nitrogen adsorption isotherm measurement data. Remarkably, perfect performance was obtained as evaluated by electrochemical measurements, including a high initial discharge capacity （1444.5 mAh·g-1 at 0.1C） and excellent capacity retention （charge capacity after 50 cycles was stil greater than 1100.0 mAh·g-1 at 0.1C）. However, its rate capability was stil not adequate （75.3%of the first charge capacity after 50 cycles at 1C）. To improve the rate capability, commercial carbon nanotubes （CNTs） mixed with the Co3O4 powder was used to enhance the electronic conductivity. The charge capacity retention ratios were 96.3%after 70 cycles at 1C and 97.0%after 50 cycles at 2C. Therefore, enhanced electrochemical performance with impressive rate capability was obtained, as expected.

关 键 词：CO3O4 片状 碳纳米管 锂离子电池 负极 

分 类 号：TM912[电气工程—电力电子与电力传动]