镁合金负极在复合电解液中电化学行为研究

发布时间：2018-08-19 14:46

【摘要】：镁电池具有环境友好、放电性能优异、工作温度范围宽、成本低等优点，成为研究热点，并且我国的镁储量丰富，在开发镁电池方面具有独特优势。但是由于镁合金的耐腐蚀性能差，在电池使用中影响了电池使用寿命，以及放电时会出现电压滞后现象，，制约着镁电池的发展。目前，镁电池的研究内容主要有电极材料的研究，镁合金负极在单组分电解液中电化学行为研究和单组分电解液中添加剂的研究，对镁合金负极在复合电解液中的电化学行为研究较少，因此研究复合电解液对镁电池的发展有重要意义。论文以研究镁合金负极在单组分电解液中电化学行为，提出了包括二组分、三组分的镁电池复合电解液体系。利用线性电位扫描、开路电位测试、交流阻抗测试、恒流放电测试、电压滞后时间测试、扫描电镜、红外光谱等方法对镁电极在复合电解液中电化学性能以及浸泡时间对电极的电化学行为和电极表面膜层的影响进行了研究。结果表明：在MgSO4溶液中，随浸泡时间增加，镁合金腐蚀严重，电压滞后时间较长；在Mg(ClO4)2溶液中，随浸泡时间增加，电压滞后时间能够维持在2s内。在Mg(ClO4)2+La(NO3)3溶液中，耐蚀性能得到提高，电压滞后时间较短，放电过程中电位不平稳；在Xmol/L Mg(ClO4)2+Ymol/L MgSO4+0.05mol/LLa(NO3)3(X=0.5,0.67；Y=1,0.67)三组分溶液体系中，Mg(ClO4)2和MgSO4的添加量对电压滞后时间影响不大，随浸泡时间增加，电压滞后时间在2s内，放电平稳，La(NO3)3组分的加入提高了耐蚀性能；在1mol/L Mg(ClO4)2+Zmol/L MgSO4(Z=0.5,1.0)+0.05mmol/L La(NO3)3三组分溶液中，MgSO4浓度增加，腐蚀加速，电压滞后时间缩短。综合考虑，0.67mol/L Mg(ClO4)2+0.67mol/L MgSO4+0.05mol/L La(NO3)3三组分电解液是较优复合电解液，具有放电平稳，电压滞后时间短，耐蚀性能好等优点。
[Abstract]:Magnesium batteries have many advantages such as friendly environment, excellent discharge performance, wide range of operating temperature, low cost and so on. It has become a research hotspot in China, and has a unique advantage in the development of magnesium batteries because of its rich magnesium reserves. However, due to the poor corrosion resistance of magnesium alloy, the battery life is affected in battery use, and voltage lag occurs during discharge, which restricts the development of magnesium battery. At present, the main research contents of magnesium battery include electrode material, electrochemical behavior of magnesium alloy negative electrode in one component electrolyte and additives in one component electrolyte. There is little research on the electrochemical behavior of magnesium alloy anode in the composite electrolyte, so it is important to study the composite electrolyte for the development of magnesium battery. In order to study the electrochemical behavior of magnesium alloy negative electrode in single component electrolyte, a two-component and three-component magnesium battery composite electrolyte system was proposed. Linear potential scan, open circuit potential test, AC impedance test, constant current discharge test, voltage lag time test, scanning electron microscope, The electrochemical properties of magnesium electrode in composite electrolyte and the influence of immersion time on the electrochemical behavior of the electrode and the film layer on the surface of the electrode were studied by infrared spectroscopy. The results show that in MgSO4 solution, the corrosion of magnesium alloy is serious with the increase of immersion time, and the voltage lag time is longer in mg (ClO4) _ 2 solution, and the voltage lag time can be maintained within 2 seconds with the increase of immersion time in mg (ClO4) _ 2 solution. In mg (ClO4) _ 2La (NO3) _ 3 solution, the corrosion resistance of mg (ClO4) _ 2La (NO3) _ 3 solution was improved, the voltage lag time was shorter, the potential was not stable during discharge, and the addition of mg (ClO4) _ 2 and MgSO4 had little effect on the voltage lag time in the Xmol/L mg (ClO4) _ 2 Ymol/L MgSO4 0.05mol/LLa (NO3) _ 3 (XY _ (0.5) 0.67) _ (0.67) solution system. With the increase of immersion time, the corrosion resistance of La (NO3) _ 3 was improved by the addition of La (NO3) _ 3, and the concentration of MgSO _ 4 in 1mol/L mg (ClO4) _ 2 Zmol/L MgSO4 (Z _ (0.5) Zmol/L MgSO4) _ (1.0) 0.05mmol/L La (NO3) _ 3 solution increased, the corrosion accelerated and the voltage lag time shortened. It is considered that 0.67 mol / L mg (ClO4) 2 0.67mol/L MgSO4 0.05mol/L La (NO3) 3 electrolyte is an excellent composite electrolyte with the advantages of stable discharge, short voltage lag time and good corrosion resistance.
【学位授予单位】：重庆大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TM911.1;O646

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