Cu单掺杂和Cu/Al复合掺杂纳米氢氧化镍的结构和电化学性能

摘要

Nanometer Cu singly doped and Cu/Al co-doped nickel hydroxides were synthesized by ultrasonic-assisted precipitation method.Their crystal structure, particle size,morphology,tap density and electrochemical performance were investigated.The results show that the samples have α-phase structure with narrow particle size distribution.Cu singly doped nano-Ni(OH)2 contains irregular particles,while Cu/Al co-doped nano-Ni(OH)2 displays a quasi-spherical shape and has a relatively higher tap density.Composite electrodes were prepared by mixing 8％ (mass fraction) nanometer samples with commercial micro-size spherical nickel.The charge/discharge test and cyclic voltammetry results indicate that the electrochemical performance of Cu/Al co-doped nano-Ni(OH)2 is better than that of Cu singly doped nano-Ni(OH)2,the former's discharge capacity reaches 330 mA·h/g at 0.2C,12 mA.h/g and 91 mA.h/g larger than that of Cu singly doped sample and pure spherical nickel electrode,respectively.Moreover,the proton diffusion coefficient of Cu/Al co-doped sample is 52.3％ larger than that of Cu singly doped sample.%采用超声波辅助沉淀法制备Cu单掺杂和Cu/Al复合掺杂的纳米Ni(OH)2样品,测试样品的晶相结构、粒径、形貌、振实密度及电化学性能.结果表明,样品均具有α相结构且其平均粒度的分布范围窄,Cu单掺杂的纳米Ni(OH)2呈现不规则形态,而Cu/Al复合掺杂的纳米Ni(OH)2呈准球状且具有更大的振实密度.将纳米样品以8％的比例掺入到商业用微米级球形镍中制成混合电极.充放电和循环伏安测试结果表明,Cu/Al复合掺杂纳米Ni(OH)2的电化学性能优于Cu单掺杂的纳米Ni(OH)2的,前者的放电比容量最高达到330 mA.h/g (0.2C),比Cu单掺杂样品的高12 mA.h/g,比纯球镍电极的高91 mA.h/g.此外,Cu/Al复合掺杂纳米样品的质子扩散系数比Cu单掺杂样品的高52.3％.