喷雾热解制备镍/锰氧化物粉体及其超级电容特性

Supercapcitive Properties of Nickel/Manganese Oxide Powder Prepared by Spray Pyrolysis

以醋酸锰与醋酸镍作为先驱物,以喷雾热解法在500℃下,制备具中空球状结构的镍/锰氧化物复合粉体作为超级电容的活性材料,再通过电泳披覆法将粉末沉积于石墨基材上作为电容电极.利用循环伏安法来探讨其电容特性与循环寿命,所得复合粉体以XRD,SEM与HR-TEM等仪器进行微结构观察,探讨其对电容特性的影响.结果表明,少量的镍含量会使氧化锰晶格产生形变,有助于提高其比电容值约210F/g.此外,当镍的含量增多,会导致镍/锰氧化物的衍射峰逐渐宽化,由HR-TEM分析氧化锰则有非晶质化的现象,显示镍会抑制锰氧化物的结晶性,进而使循环寿命下降.在添加少量[1.0%(mol)]镍的锰氧化物,由于其结晶性较佳,使得其循环寿命在1200次的测试后仍能维持在81%.

Nanocrystalline nickel/manganese oxide particles with a hollow structure were prepared by spray pyrolysis from manganese acetate and nickel acetate solutions at 500℃.The as-obtained powder was subsequently coated onto graphite substrate to be the supercapacitor electrode via an electrophorectic deposition technique.The supercapacitive properties such as specific capacitance(SC) and cycle life of the coatings were examined by cycling voltammetry.The phase identification of as-prepared powder was performed by XRD.Their microstructure was observed by SEM and HR-TEM.Experimental results showed that a small amount of nickel addition led the lattice deformation of manganese oxide,increasing the specific capacitance to 210 F/g.However,with further increasing the nickel addition,the diffraction peaks of manganese oxide phase were broadened.This amorphization in manganese oxide was also examined by HR-TEM,showing that the nickel addition inhibited the crystallinity of manganese oxide.Compared with its capacitive properties,the low crystallinity of manganese oxide powder tended to reduce its cyclic efficiency.Nevertheless,1.0%(mol) nickel-added manganese oxide still exhibited a high SC efficiency of 81% after 1200 cycles of cyclic voltammogram test.