锌镍电池正极材料氢氧化镍研究

发布时间：2018-03-09 21:08

本文选题：锌镍电池　切入点：正极材料　出处：《昆明理工大学》2017年硕士论文　论文类型：学位论文

【摘要】：锌镍电池比能量高,比功率大,开路电压达1.73V,工作温度范围宽广,可大电流充电,原材料丰富且成本低,环保。该电池作为新能源的绿色电源具有很大的发展与应用潜力。本文通过查阅国内外相关文献对氢氧化镍的制备方法,如液相沉淀法、均相沉淀法、水热法、氧化法、高压水解法、离子交换树脂法、微乳液法、电解法和机械化学合成法等进行叙述;阐述了各种制备工艺对制得的氢氧化镍材料结构、形貌、尺寸和容量等方面的影响。进一步综述掺杂氢氧化镍制备工艺方法并分析添加元素对氢氧化镍结构、容量、电化学性能的影响。同时,也介绍了锌镍电池特点、结构、工作原理、存在的问题及其解决方式、镍电极片种类及其压制工艺。采用X射线衍射(XRD)、扫描电镜(SEM)、电化学阻抗谱、循环伏安特性曲线(CV)、极化曲线、恒流充放电测试等手段对制备的材料进行表征与测试。研究液相沉淀法制备氢氧化镍时,对反应体系pH、氨水浓度、反应物浓度、搅拌强度等最佳工艺参数进行确定,得出反应体系pH的最佳值为10.5、最佳氨水浓度为2mol/L、最佳反应物NiSO4浓度为1.2mol/L、搅拌强度为220r/min。在该条件下制备出的氢氧化镍最大振实密度可达1.53g/cm3;加入晶种对氢氧化镍形貌影响较小,添加20%的晶种量提升氢氧化镍颗粒紧实性和宏观材料振实密度;并研究了聚乙烯2000、聚乙烯吡咯烷酮、十六烷基三甲基溴化铵作为表面活性剂时,对氢氧化镍产品的形貌和振实密度提升效果最显著的是聚乙烯吡咯烷酮。采用液相沉淀超声波辅助的方法,顺利制备出了球形氢氧化镍。研究中发现超声波强度对氢氧化镍形貌有一定影响。发现超声波强度氢氧化镍材料颗粒表面有显著的修饰作用;同时确定了制备球形氢氧化镍适当的超声波功率强度在216W左右,所得氢氧化镍粒度为10μm左右的β-Ni(OH)2;对制备的球形Ni(OH)2进行电极压制测试,在0.4 C充电3 h,静置3min,1C放电至1.2 V的充放电制度对镍电极进行放电性能测试测得该材料所制得的氢氧化镍材料放电比容量可达260 mAh/g。采用化学沉淀法在商品球形氢氧化镍表面进行覆钴研究,研究了覆着不同钴量的氢氧化镍对电极内阻、极化、电极容量、耐蚀性、循环稳定性方面的影响。发现球形氢氧化镍在覆着钴后,对改善电极性能有作用,确定了覆钴最佳含量3%,测试发现覆钻的镍电极在0.2C充电6h,静置5min,0.2C放电至1.2V的充放电制度循环40次后循环保持率为83.2%。
[Abstract]:Zn-Ni battery has high specific energy, high specific power, open circuit voltage of 1.73 V, wide working temperature range, large current charging, abundant raw materials and low cost. Environmental protection. The battery as a new source of green power has great potential for development and application. In this paper, the preparation methods of nickel hydroxide, such as liquid precipitation method, homogeneous precipitation method, hydrothermal method, oxidation method, are reviewed. The high pressure hydrolysis method, ion exchange resin method, microemulsion method, electrolysis method and mechanochemical synthesis method were described. The effects of doping nickel hydroxide on the structure, capacity and electrochemical properties of nickel hydroxide were reviewed. The characteristics and structure of zinc nickel battery were also introduced. Working principle, existing problems and their solutions, kinds of nickel electrode plates and their pressing technology. X-ray diffraction (XRD), scanning electron microscopy (SEM), electrochemical impedance spectroscopy (EIS), cyclic voltammetry (CV), polarization curves, etc. In the preparation of nickel hydroxide by liquid-phase precipitation, the optimum technological parameters, such as pH of reaction system, concentration of ammonia water, concentration of reactant and stirring intensity, were determined. The optimum pH value is 10.5, the optimum ammonia concentration is 2 mol / L, the optimal reactant NiSO4 concentration is 1.2 mol / L, and the stirring intensity is 220 r / min. The maximum vibrational density of nickel hydroxide prepared under these conditions is 1.53 g / cm ~ 3, and the effect of adding seed on the morphology of nickel hydroxide is small. The particle compactness of nickel hydroxide and the vibrational density of macroscopical materials were improved by adding 20% seed quantity, and the effects of polyethylene 2000, polyvinylpyrrolidone and cetyltrimethylammonium bromide as surfactants were studied. Polyvinylpyrrolidone is the most effective method for enhancing the morphology and density of nickel hydroxide. Spherical nickel hydroxide was successfully prepared. It was found that ultrasonic intensity had a certain influence on the morphology of nickel hydroxide. At the same time, the supersonic power intensity of preparing spherical nickel hydroxide is about 216W, and the particle size of nickel hydroxide is about 10 渭 m. After charging at 0.4 C for 3 h, the discharge performance of nickel electrode was measured by charging and discharging from 1C to 1.2 V at 3min. The discharge capacity of nickel hydroxide material was up to 260mAh/ g. Spherical hydrogen hydroxide was prepared by chemical precipitation method. Cobalt coating on the surface of nickel oxide, The effects of nickel hydroxide coated with different cobalt content on the internal resistance, polarization, electrode capacity, corrosion resistance and cyclic stability of the electrode were studied. It was found that spherical nickel hydroxide could improve the performance of the electrode after cobalt coating. The optimum content of cobalt covered with cobalt was determined. It was found that the nickel electrode was charged at 0.2C for 6 h, and the charge and discharge rate was 83.2 after 40 cycles of discharge from 0.2C to 1.2V at 5 mins.
【学位授予单位】：昆明理工大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TM912;TQ138.13

【参考文献】