钒氧化物纳米管的合成、结构及电化学性能

Synthesis,Structure and Electrochemical Performance of Vanadium Oxide Nanotubes

采用流变相 -纳米自组装新方法合成了钒氧化物纳米管 ( VOx-NTs) ,并通过 XRD,SEM,TEM,Raman,ESR,TG-DTA,XPS及模拟电池等技术手段对产物的结构和性能进行了表征和测试 .结果表明 ,产物主要由钒氧化物纳米管组成 ,纳米管长为 1～ 1 0 μm,直径为 3 0～ 1 0 0 nm.纳米管壁由 3～ 1 0个 VOx 层构成 ,层间距为 3 .5 3 nm.Raman光谱反映了 V— O的伸缩或弯曲振动 ,层状微结构的晶格振动及模板剂的有机基团振动 .无明显精细结构的室温 ESR谱证明了 V4 +的存在 ,根据 TGA和 XPS求得产物中 V的平均化合价约为 + 4 .3 0 .VOx-NTs正极材料初始充电容量达到 40 4m A.h/g,放电容量为 3 83 m A.h/g,5 0次循环后放电容量衰减至 1 80 m A.h/g,可归因于充放电过程中 VOx-NTs正极材料在电解液中的溶蚀作用及复合电极中“孤岛效应”

Vanadium oxide nanotubes (VO x-NTs) were synthesized in a rheological phase reaction followed by self-assembling process and characterized by XRD, SEM, TEM, Raman, ESR, TG-DTA, XPS, and simulated battery. The results show that the black products consist majority of VO x-NTs with length of 1—10 μm and diameter of 30—100 nm, whose walls consist of 3—10 VO x layers with interlayer distance of 3.53 nm. Raman spectrum indicates the stretching or bending vibration of V—O, lattice vibration of layered structure and organic group vibration of template. ESR spectrum with no superfine structure confirms the presence of V 4+ and the average valence of vanadium in the product is +4.30 on the basis of TG and XPS. The initial charge and discharge capacity of VO x-NTs are 404 and 383 mA·h/g, respectively. The discharge capacity decreases to 180 mA·h/g after 50 cyclee, which can be attributed to the VO x-NTs reacting with the electrolyte and isolating from the carbon particles during the charge-discharge.