Ti和TiN基底上阳极氧化膜的制备、掺杂及电化学性能研究

发布时间：2018-11-29 12:43

【摘要】：金属钛的阳极氧化膜分为两种,TiO_2纳米管(多孔膜)和致密膜。TiO_2纳米管具有有序的多孔结构、大比表面积,可作为超级电容器的电极材料。尽管TiO_2纳米管已研究多年,但因Ti片上制备的TiO_2纳米管易剥离、电化学性能较差等缺点使应用受限。因此,本文首先对比了 Ti丝、Ti片两种基底,在不同阳极氧化条件下,制备的TiO_2纳米管形貌和电化学性能的差异。其次,为了提高TiO_2纳米管的比电容,研究了 N掺杂的TiO_2纳米管的两种制备方法(一步法、二步法),并与未掺杂的TiO_2纳米管的性能相比较。再次,为了简化掺杂工艺,直接在沉积有TiN涂层的Ti片(TiN-Ti)基底上进行不同条件下的阳极氧化,得到电化学性能更好的含N的TiO_2纳米管,为超级电容器电极材料的制备提供指导。最后,尽管TiO_2致密膜可作为电容器的电介质材料,但与TiO_2纳米管相比,TiO_2致密膜却很少有人研究。因此,本文还研究了不同基底上、不同条件下致密膜的制备,并对比了致密膜的漏电流及不同频率下的比电容和损耗。全文的主要工作如下:首先,由于Ti丝上制备的TiO_2纳米管与基底结合力较好,因此系统研究了不同阳极氧化条件下Ti丝上制备的TiO_2纳米管的形貌与电化学性能,并与Ti片上制备的TiO_2纳米管相比较。实验表明,NH_4F浓度越大、温度越高,Ti丝上制备出的TiO_2纳米管的管长越长、比电容越大。其次,分别使用一步法及二步法在Ti片上制备出N掺杂的纳米管。一步法是将Ti片在含尿素的电解液中氧化生成N掺杂的纳米管,二步法是将常规制备出的TiO_2纳米管在氨水或尿素溶液中浸渍。两种方法制备出的N掺杂的TiO_2纳米管均获得更大的比电容,但是浸渍后的纳米管与基底的结合力较差,因此一步法更具有优势。另外,将TiN-Ti在常规电解液中阳极氧化制备出含N的TiO_2纳米管,研究了氧化时间及温度对纳米管的影响。与相同时间下Ti片上生长的纳米管相比,TiN-Ti上生长的管长较短,单位长度上具有更高的比电容。随着温度的升高,TiN-Ti上制备的纳米管管长变长,比电容提高。最后,为了探索致密膜的阳极氧化工艺,研究了电解液种类、氧化电压、温度对TiN-Ti及Ti片上生长的致密膜性能的影响。四种电解液对比结果表明,电解液种类对Ti片上致密膜性能影响不大,但TiN-Ti在NH_4B_5O_8与H_3BO_3混合溶液中制备的致密膜性能最好。与Ti片上致密膜相比,在TiN-Ti上生长的致密膜的漏电流和损耗性能更优。实验表明,TiN-Ti生长的致密膜性能与Ti片上的相似,随着氧化电压的升高,漏电流增加,比电容下降,损耗减小;而随着温度的升高,漏电流增加,比电容下降,损耗增加。
[Abstract]:There are two kinds of anodic oxide films of titanium, TiO_2 nanotubes (porous films) and dense films. TiO_2 nanotubes have ordered porous structure and large specific surface area, so they can be used as electrode materials for supercapacitors. Although TiO_2 nanotubes have been studied for many years, the application of TiO_2 nanotubes prepared on Ti wafers is limited due to their easy peeling and poor electrochemical performance. Therefore, the morphology and electrochemical properties of TiO_2 nanotubes prepared under different anodic oxidation conditions were compared between Ti wire and Ti substrate in this paper. Secondly, in order to improve the specific capacitance of TiO_2 nanotubes, two preparation methods (one-step, two-step) of N-doped TiO_2 nanotubes were studied, and the properties of N-doped TiO_2 nanotubes were compared with those of undoped TiO_2 nanotubes. Thirdly, in order to simplify the doping process, TiO_2 nanotubes with better electrochemical properties were obtained by anodizing directly on the Ti (TiN-Ti) substrate deposited with TiN coating under different conditions. To provide guidance for the preparation of electrode materials for supercapacitors. Finally, although TiO_2 dense films can be used as dielectric materials for capacitors, TiO_2 dense films are rarely studied compared with TiO_2 nanotubes. Therefore, the preparation of dense films on different substrates and different conditions were studied, and the leakage current and specific capacitance and loss at different frequencies were compared. The main work of this paper is as follows: firstly, the morphology and electrochemical properties of TiO_2 nanotubes prepared on Ti wires under different anodic oxidation conditions are studied systematically because of the good adhesion between the TiO_2 nanotubes prepared on Ti wires and the substrate. And compared with TiO_2 nanotubes prepared on Ti wafer. The experimental results show that the larger the concentration of NH_4F, the higher the temperature, the longer the length and the larger the specific capacitance of TiO_2 nanotubes prepared on Ti wires. Secondly, N doped nanotubes were prepared on Ti wafer by one step method and two step method respectively. The one-step method is to oxidize the Ti sheet in the electrolyte containing urea to form N-doped nanotubes. The two-step method is to impregnate the conventional prepared TiO_2 nanotubes in ammonia water or urea solution. Both N-doped TiO_2 nanotubes obtained larger specific capacitance, but the impregnated nanotubes have less adhesion to the substrate, so the one-step method has more advantages. In addition, TiO_2 nanotubes containing N were prepared by anodic oxidation of TiN-Ti in conventional electrolyte. The effects of oxidation time and temperature on the nanotubes were studied. Compared with the nanotubes grown on the Ti wafer at the same time, the length of the grown nanotubes on the TiN-Ti is shorter and the specific capacitance per unit length is higher. With the increase of temperature, the length and specific capacitance of nanotubes prepared on TiN-Ti become longer and higher. Finally, in order to explore the anodizing process of dense films, the effects of electrolyte type, oxidation voltage and temperature on the properties of dense films grown on TiN-Ti and Ti were studied. The results of comparison of four electrolytes show that the type of electrolyte has little effect on the properties of dense films on Ti, but the properties of dense films prepared by TiN-Ti in the mixed solution of NH_4B_5O_8 and H_3BO_3 are the best. Compared with the compact film on Ti, the leakage current and loss performance of the compact film grown on TiN-Ti are better. The experimental results show that the properties of the dense film grown by TiN-Ti are similar to those on Ti. With the increase of oxidation voltage, the leakage current increases, the specific capacitance decreases and the loss decreases, but with the increase of temperature, the leakage current increases, the specific capacitance decreases and the loss increases.
【学位授予单位】：南京理工大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TB306

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