【作者】 郭彩峰；

【导师】 石秋芝； 杨长春；

【作者基本信息】 郑州大学 ， 物理化学， 2005， 硕士

【摘要】 本论文对由氢氧化镍经电化学氧化和化学氧化两种方法制备羟基氧化镍的工艺条件进行了较为系统的研究。羟基氧化镍是一种用于锌/氧化镍等一次电池的重要的正极活性材料。本论文重点研究了以苛性碱为电解液电解氧化球形氢氧化镍制备球形羟基氧化镍的电化学氧化法。采用粉末X-衍射（XRD）、扫描电镜（SEM）、循环伏安（CV）、组装实验电池进行性能测试等实验技术,探讨了工艺参数,如:电解液种类与浓度、电解液温度、电解持续时间等,对所制羟基氧化镍的氧化度、晶型结构、松装和振实密度等性能参数的影响。主要结论如下: 1.带搅拌装置的圆柱形隔膜电解槽较其它结构形式的电解槽,更适于电解氧化Ni（OH）₂制备NiOOH。隔膜材料选用维尼纶无纺布即可满足要求。 2.选用Ni（OH）₂为原材料,可以避免引入其它对电池性能有害的杂质。在Ni（OH）₂中添加Co（OH）₂可以加快其氧化速度,对γ-NiOOH的形成也有一定的抑制作用。 3.所制NiOOH的结构形态,受电解液苛性碱性质及浓度影响较大。浓度小于5.0M的纯KOH电解液中,β-Ni（OH）₂的电解氧化产物主要是β-NiOOH;浓度大于5.0M的纯KOH电解液中,β-Ni（OH）₂的电解氧化产物主要是γ-NiOOH。浓度小于7.0M的NaOH电解液中,β-Ni（OH）₂的电解氧化产物主要是β-NiOOH;浓度大于7.0M的NaOH电解液中,β-Ni（OH）₂的电解氧化产物主要是γ-NiOOH。 4.由NaOH,KOH,LiOH组成三元混合电解液,即可保证电解液的导电性,又能使所制NiOOH主要呈现β-NiOOH的结构,有效地抑制γ-NiOOH的形成。最佳电解液组成为:4-5M KOH+4-5M NaOH+20g/L LiOH 5.电解前固体Ni（OH）₂在电解液中预浸泡,可提高电解氧化速度。预浸泡时间为1-2小时,既可满足要求。 6.随着电解温度的升高（≤80℃）,以NaOH为电解液的体系氧化速度会逐渐升更多还原

【Abstract】 In this thesis, two techNiques-electrochemical oxidation and chemical oxidation, for synthesis NiOOH from Ni（OH）₂, which was an important cathode active material for some primary batteries, e.g. Zn/NiOOH, were investigated systematically. The emphasis was put（?） upon the production of spherical NiOOH by electrolytic oxidation Ni（OH）₂ in the caustic alkali electrolyte. The effects of technology parameters, e.g. the nature and concentration of caustic alkali electrolyte, the electrolyte temperature, the duration of electrolysis time and so on , upon the properties of the produced NiOOH, e.g. oxidation degree, bulk density, tap density, crystal structure etc. were probed by using several methods, such as, powder X-ray diffraction （XRD）, scanNing electron microscope （SEM）, cyclic voltammetray （CV）, chemical analysis, and charge and discharge feature of experimental battery, etc. The main conclusions were as below:1. Comparing with other cell, a divided two compartment cylinder cell separated by membrane with stirring equipment, was more suitable for electrolyzing Ni（OH）₂ to produce NiOOH. The adhesive bonded vinylon fabric cloth could meet the requirement of membrane.2. The impurities toxic to battery performance could not be introduced, using Ni（OH）₂ as source material. The speeds of electrochemical oxidation of Ni（OH）₂ to NiOOH were accelerated by adding some Co（OH）₂ powder in Ni（OH）₂, and it was favor for preventing the formation of γ-NiOOH.3. The nature and concentration of electrolyte affected the crystal structure of the produced NiOOH sigNificantly. When KOH solutions were used as electrolyte, if the concentration was lower than 5.0mol/L, the final product by electrochemical oxidation was 6-NiOOH; while the final product was γ-NiOOH if the concentration was higherthan 5.0mol/L. When NaOH solutions were used as electrolyte, if the concentration was lower than 7.0mol/L, the final product was 6-NiOOH; while the final electrochemical oxidized product was y-NiOOH if the concentration was higher than 7.0mol/L.4. Three components electrolyte contaiNing NaOH, KOH and liOH, has a good conductivity and could prevent the formation of y-NiOOH. The products produced using this electrolyte mainly appeared as B-NiOOH. The determined optimum component was: 4-5mol/LKOH + 4-5mol/LNaOH +20g/LLiOH5. The rates of electrochemical oxidation of Ni（0H）2 to NiOOH were accelerated by pre-immersing Ni（0H）2 in electrolyte before electrolysis. The duration time meeting the requirement of immersion was 1-2 hours.6. As the temperature of the electrolytic process get higher（ = SCPC）, the electrolytic oxidation speed of the system which use NaOH as electrolyte can get higher gradually. But the electrolytic oxidation speed of the system which use KOH as electrolyte get lower if the temperature of the electrolyse process exceed 6(^0. As the current density get higher, the oxidation speed get higher accordingly, but the current efficiency get lower.7. The result of SEM shown that, spherical 8-NiOOH could be produced by electrochemical oxidizing spherical B-Ni（0H）2. Even at a proper high oxidation degree, using this method, the spherical grain shape ofB-Ni（OH）2 could be preserved quite well in the product of B-NiOOH. Because of the cell volume expansion appeared during the formation of y—NiOOH from the over oxidation of B-NiOOH, the grain shape of spherical y—NiOOH were destroyed greatly.8. Because it is difficult to control the oxidation degree of NiOOH, using chlorine and hypochlorate to oxidize Ni（0H）2, the products produced by chemical oxidation could be easily transformed to y—NiOOH from B-NiOOH. The grains of the product with an irregular shape were easily assembled as colloidal sediment, leading a difficulty for washing.更多还原