CAJ | 학술논문

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-Tel er (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.
채용액상침정법결합저온고상열해법합성료리리자전지편상Co3O4부겁.통과X사선분체연사(XRD)、Brunauer-Emmett-Tel er (BET)비표면적분석、소묘전자현미경(SEM)급항전류충방전등표정수단,발현해Co3O4위립방상,결정완정차무잡질,유직경위1.5-3.0μm、후도약위100-300 nm적불규칙편상과립조성,비표면적약위30.5 m2?g-1；기비용량고차용량보지솔호,재0.1C배솔하,수차방전용량고체1444.5 mAh?g-1,50차순배후충전용량잉대우1100.0 mAh?g-1；단재고배솔(1C)하,50차순배후충전용량보지솔부위75.3%,배솔성능일반.고채용탄납미관(CNTs)참잡개성,결과표명：재1C배솔하,70차순배후복합재료충전용량보지솔위96.3%；재2C배솔하,50차순배후충전용량보지솔잉고체97.0%,배솔성능현저제승.
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.