CO_3^(2-)/Co^(2+)/Ni^(2+)浓度对混合相纳米Ni(OH)_2物化性能的影响  

Effect of the CO_3^(2-)/Co^(2+)/Ni^(2+) Concentration on the Physicochemical Properties of Mixed Phase Nano-Ni(OH)_2

作　　者：庄义环[1] 朱燕娟[1] 赵汝冬[1] 林晓然[1] 刘泳林[1] 张树杰[1] 许庆胜[1] 

机构地区：[1]广东工业大学物理与光电工程学院,广州510006

出　　处：《无机化学学报》2013年第2期338-344,共7页Chinese Journal of Inorganic Chemistry

基　　金：国家自然科学基金(No.10774030);广东省自然科学基金(No.S2012010009955);广东省大学生创新创业训练项目(No.1184512230);广州市科技计划(No.12C232111916)资助项目

摘　　要：以NiCl2、Co(NO3)2、Na2CO3为主要原料,采用超声波辅助沉淀法制备了混合相纳米Ni(OH)2,研究了Co掺杂比例、缓冲剂Na2CO3用量及反应物Ni2+浓度对Ni(OH)2的晶相结构、形貌、粒径及电化学性能的影响。结果表明,混合相结构的α-Ni(OH)2成分随Co掺杂比例增大而增加。较高的CO32-和Ni2+浓度有利于α-Ni(OH)2的生成。TEM测试表明,样品晶粒呈针状形态,其长径比随着Na2CO3用量增加而减小,平均粒度在60~90 nm之间。将纳米样品以8wt%与工业用微米级β球镍混合制成复合电极,其电极的放电比容量随Na2CO3用量的增加先增大后减小。当Ni2+浓度为0.4 mol.L-1、Na2CO3用量为0.5 g时,其电极(Co含量1.02wt%)的充电效率最高,放电比容量最大,0.5C倍率下高达306.9 mAh.g-1,比纯球镍电极提高30%。探讨了复合电极能较大幅度提高放电比容量的机理,提出纳米α-Ni(OH)2同时充当活化中心起催化作用的观点。The mixed phase nanometer Ni（OH）2 was prepared by ultrasonic-assisted precipitation method using NiCl2,Co（NO3）2 and Na2CO3 as main materials. The crystal structure, morphology, particle size distribution and electrochemical performance affected by doping ratio, buffer and Ni2 ＋ concentration were characterized. The results indicate that different Co-containing Ni（OH）2 were co-existence with α and/3 phase and the proportion of α-Ni（OH）2 significantly increase with the increase of doping ratio. The higher CO3^2- and Ni2＋ concentration is beneficial to form α-Ni（OH）2. The transmission electron microscope （TEM） results show that all samples have the needle-like morphology, the length-diameter ratio decreased with the increase of Na2CO3 and the average particle size was between 60 ~90 nm. Composite electrodes were prepared by mixing 8wt% nickel hydroxides with commercial micro-size spherical nickel. The discharge capacities of electrodes increased initially and then decreased with the increase of Na2CO3. When Ni2＋ is 0.4 mol·L^-1 and Na2CO3 is 0.5 g, the electrode （the Co is 1.02wt%） has the largest discharge capacity, which reaches 306.9 mAh.g^-1 at 0.5C rate, and is 30% higher than that of spherical nickel electrode. The mechanism was investigated to explain the larger discharge capacity, proposing that nanometer α-Ni（OH）2 act as activation center played a catalytic role.

关 键 词：缓冲剂Na2CO3 反应物浓度 混合相纳米Ni(OH)2 超声波辅助沉淀法 电化学性能 

分 类 号：O646[理学—物理化学] TQ174[理学—化学]