超声波功率和pH值对Y掺杂纳米Ni(OH)_2结构与性能的影响

Effect of Supersonic Power and pH Value on the Structure and Electrochemical Performance of Y Doped Nano-Ni(OH)_2

采用超声波沉淀法制备了Y掺杂纳米Ni(OH)2,研究了超声波功率和溶液pH值对材料结构、粒径及电化学性能的影响。结果表明,不同超声波功率制备的样品均为α和β混合相结构,其中α-Ni(OH)2的比例随功率增大先增加后减少,粒径随功率增大先减小后增大。溶液pH值对Ni(OH)2晶相形成起重要作用,较低的pH值有利于α-Ni(OH)2生成,晶粒粒径随pH值增大而增大,但pH值对电极反应的可逆性影响不大。将样品以8%(质量分数)与工业用微米级球镍混合制成复合电极,其电极的放电比容量随功率增大先提高后下降。功率为60W,pH值为9的样品,其相应电极的充电效率最高,放电比容量最大,0.5C倍率下高达358mAh/g。

Nano-Ni（OH）2 doped with yttrium was prepared by supersonic co-precipitation method.The crystal structure and electrochemical performance affected by supersonic power and pH value were characterized.The results indicate that the nickel hydroxides prepared under different ultrasonic power were co-existence with α and β phase,which were.As the supersonic power increases,the proportion of α-Ni（OH）2 increased initially and then decreased,but the particle size is converse.PH value is very important to the formation of crystalline phase.Lower pH value is beneficial to formation of α-Ni（OH）2,which is decreased with the pH value increased.However,the pH values have a slight effect on the reaction reversibility.Complex electrodes were prepared by mixing 8%（mass fraction） nickel hydroxides with commercial micro-size spherical nickel.The discharge capacities of electrodes increased initially and then decreased with the increase of superonic power.When the supersonic power is 60W and the pH value is 9,the sample has the largest discharge capacity,which reaches 358mAh/g at 0.5C rate.Furthermore,the sample（P=60W,pH=9） has better electrochemical performance and higher charge or discharge potential than the others.