新型氮化钨化合物的制备与表征

SYNTHESIS AND CHARACTERIZATION OF NEW TUNGSTEN NITRIDES

郭奇松

11649144

硕士

材料工程

赵予生

2018-05-30

2018-07-05

哈尔滨工业大学

深圳

超级电容器在电化学能量储存设备中一直占有十分重要的地位，这是因为超级电容器具有较高的功率密度、能量密度以及长时间的循环寿命，因此得到了人们广泛的重视。过渡金属氮化物具有很好的化学稳定性、高的耐腐蚀性、很高的熔点、高的显微硬度，高的密度和很小的电阻率，因此被人们用来作为电极材料进行研究。本文中主要通过高温制备的方法制备得到了过渡金属氮化钨，此外在氮化钨合成的过程中，温度、M（氮化硼与钨酸钠的摩尔比）等因素产生的影响也进行了探究，然后对900 ℃条件下合成的立方氮化钨进行石墨烯的复合，通过电化学工作站等手段对材料的电化学性能进行测试，并分析材料的结构形貌对于其电化学性能的研究，并对其形成的机理进行探究，本课题的主要内容总结如下：（1）以BN 和Na2WO4 为原料，通过高温制备的方法合成得到了过渡金属氮化钨，在实验过程中我们通过控制不同的原料的摩尔配比以及温度的变化和保温时间的长短等因素合成出了一些列的不同W-N 含量比的样品，其中当合成温度为900 ℃时候制备出了近似于化学计量比的立方氮化钨。其中在750℃时候对于r-W2N3 的制备是很有益的而900 ℃更利于制备c-WN,其次对于原料的摩尔比也就是M 值对于实验结果的影响为当M 值是2:3 时候，制备的样品在反应程度以及c-WN 的生成量中比M 值为1:2 的时候更为有优势。（2）以c-WN 作为母材料对其进行石墨烯的复合，材料的复合主要是借助于静电作用的原理。对c-WN 和WN@石墨烯材料进行电化学性能测试，研究结果表明WN 在电流密度为0.1 A/g 时候得到的比电容80.5 mF.cm-2 是高的；对于WN@石墨烯材料，当扫描速度为5 mV/s 时候测试得到的比电容为124.9 mF.cm-2,当电流密度为0.2 A/g 时候，测试得到的比电容为120.8 mF.cm-2,所测得比容量高于氮化钨的比容量，此外就循环稳定性而言，其在3000 次循环后的比电容保持率为77.1%高于c-WN 的保持率53.3%。这说明了对氮化钨进行石墨烯复合制备有利于提高氮化钨的电化学性能。

Supercapacitors have always played an important role in electrochemical energy storage devices. This is because supercapacitors have high power density, energy density, and long cycle life, so they have received widespread attention. Transition metal nitrides have good chemical stability, high corrosion resistance, high melting point, high microhardness, high density and low resistivity, and are therefore used by people as electrodes materials for research.In this paper, tungsten nitrides of transition metals were prepared by high-temperature preparation methods. In addition, the effects of temperature, M (molar ratio of boron nitride and sodium tungstate), and other factors were also investigated during the synthesis of tungsten nitride. then compounding graphene with cubic tungsten nitride synthesized at 900 ℃are achieved by the method of Yang’s, and by means of electrochemical workstations, The electrochemical properties were tested, and the structural morphology of the material was analyzed for its electrochemical performance, and the mechanism of its formation was explored. The main contents of the subject are summarized as follows:(1) By using BN and Na2WO4 as starting materials, the transition metal tungsten nitride was synthesized by a high-temperature preparation method. In the experiment process, A series of samples with different WN content ratios were prepared by adjusting the molar ratio, temperature, and holding time, in which cubic tungsten nitride of approximately stoichiometric ratio was prepared when the synthesis temperature was 900 ℃. Among them, the preparation of r-W2N3 is very beneficial at 750 ℃, and the preparation of c-WN is more advantageous at 900 ℃. Secondly, the molar ratio of the starting materials, that is to say, the M value has an effect on the experimental results, when the M value is 2:3. The sample is more advantageous than the M value of 1:2 in the degree of reaction and the production of c-WN..(2) The graphene is composited with c-WN which is the parent material. The principle of compounding the material is the electrostatic effect. The electrochemical performance tests of c-WN and WN@graphene materials show that the specific capacitance of WN obtained at the current density of 0.1 A/g is 80.5 mF.cm-2.As WN@ graphene materials, the specific capacitance measured at a scanning speed of 5 mV/s is 124.9 mF.cm-2, and when the current density is 0.2 A/g, the specific capacitance obtained by the test is 120.8 mF.cm-2, the specific capacity measured is higher than the specific capacity of tungsten nitride, and in terms of cycle stability, the specific capacitance retention rate after 3000 cycles is 77.1% higher than the c-WN retention rate 53.3%. This shows that the graphene compound with tungsten nitride is beneficial to improve the electrochemical performance of tungsten nitride.

超级电容器 氮化钨 石墨烯 电化学性能

supercapacitor tungsten nitride graphene electrochemical performance

中文

联合培养

哈尔滨工业大学

郭奇松. 新型氮化钨化合物的制备与表征[D]. 深圳. 哈尔滨工业大学,2018.