摘要
采用水热和溶胶-凝胶相结合的方法,制备了具有良好电化学性能的新型多壁碳纳米管-Na3V2(PO4)3(MWCNT-NVP)复合材料(MWCNT的质量分数为8.74%).通过场发射扫描电子显微镜表征可知,MWCNT分散在NVP纳米颗粒之间,并起到"电子导电线"的作用.与纯Na3V2(PO4)3相比,MWCNT-NVP具有更高的比容量和更优异的循环性能.在0.2C(35.2 mA·g-1)的电流密度下,3.0-4.5 V的电压范围内,MWCNT-NVP的初始比容量为82.2 mAh·g-1.循环100次以后,比容量为72.3 mAh·g-1.在1.0-3.0 V充放电时,MWCNT-NVP的初始容量为100.6 mAh·g-1.100次循环以后,其容量保持率高达90%.同时,交流阻抗测试表明,由于MWCNT的存在,MWCNT-NVP的导电性有了显著的提高.以上结果表明,MWCNT-NVP是一种良好的锂离子电池电极材料.
We report the synthesis of a novel multiwal ed carbon nanotube-Na3V2（PO4）3 （MWCNT-NVP） composite with excellent electrochemical performance. The composite material was prepared by a hydrothermal process combined with a sol-gel method. The MWCNT-NVP composite consists of Na3V2（PO4）3 （NVP） and a smal amount of multiwal ed carbon nanotubes （MWCNTs） （8.74%（w））. The MWCNTs were successful y dispersed between the NVP nanoparticles, which was confirmed by field-emission scanning electron microscopy, and served as a kind of“electronic wire”. Electrochemical measurements show that the MWCNT-NVP composite has enhanced capacity and cycling performance compared with pristine Na3V2（PO4）3. At a current rate of 0.2C （35.2 mA·g-1）, the initial reversible discharge capacity of the MWCNT-NVP was 82.2 mAh·g-1, and 72.3 mAh·g-1 was maintained after 100 cycles when cycled between 3.0 and 4.5 V. Good cycling performance was also observed when cycling between 1.0 and 3.0 V. The initial reversible capacity was 100.6 mAh·g-1 and the capacity retention was 90%after 100 cycles. Additionally, electrochemical AC impedance showed that the electronic conductivity of MWCNT-NVP was significantly improved in the presence of the MWCNTs. These results indicate that the MWCNT-NVP composite has outstanding properties, and is thus a promising alternative for lithium-ion batteries with relatively low lithium consumption.
出处
《物理化学学报》
SCIE
CAS
CSCD
北大核心
2014年第6期1113-1120,共8页
Acta Physico-Chimica Sinica
基金
supported by the National Natural Science Foundation of China(61071040)
Leading Academic Discipline Project of Shanghai Municipal Education Commission,China(J50102)
Research and Innovation Project of Shanghai Municipal Education Commission,China~~
