磷酸钛铝锂的制备及其在锂空气二次电池中的应用

发布时间：2018-04-20 03:19

本文选题：锂离子固体电解质 + 微晶玻璃　；参考：《哈尔滨工业大学》2014年硕士论文

【摘要】：锂空气电池由于具有较高的能量密度而受到人们的关注，而传统的锂空气电池由于仅仅采用有机电解液，导致负极金属锂极易受到空气中水及二氧化碳的腐蚀，限制了锂空气电池的循环性能及稳定性能。以固体电解质制备的新型锂空气电池成为改善锂空气电池循环性能的突破。因此，制备具有高离子电导率的固体电解质成为提高锂空气电池性能的关键。本文选取LATP（Li1.3Al0.3Ti1.7(PO4)3）锂离子固体电解质为研究对象，探讨了不同制备工艺，添加剂的掺杂等对LATP锂离子固体电解质离子电导率、机械性能等的影响，，确定了制备LATP锂离子固体电解质的最佳化学计量比及工艺条件；另外，还以LATP固体电解质组装了锂空气电池，确定了锂空气电池的结构，并研究了锂空气电池的循环性能及稳定性能。采用高温固相法制备LATP锂离子固体电解质的研究发现，磷酸锂的掺杂对LATP固体电解质的离子电导率的改善不明显，而二氧化硅的掺杂可有效提高LATP固体电解质的离子电导率，在Li1.3+yTi1.7Al0.3SiyP3-yO12（y=0、0.1、0.2、0.3）中，当二氧化硅的掺杂量为y=0.1时，制备的LATP固体电解质的室温离子电导率最高，可达1.1×10-4S·cm-1。采用整体析晶法制备LATP微晶玻璃时，硼酸的掺杂可有效降低LATP玻璃的熔融温度，改善LATP固体电解质的离子电导率，当硼酸的掺杂量为70%时，制备的LATP固体电解质的室温离子电导率最高，可达9.91×10-5S·cm-1。以LATP微晶玻璃为锂离子固体电解质组装锂空气电池发现，采用10mol/L的氯化锂与0.1mol/L的氢氧化锂混合溶液为水相，制备的锂空气电池的循环性能及稳定性能较好，当采取限制容量为1mAh的方式充放电时，循环5次未出现明显电压衰减。对LATP的差热分析曲线进行了分析，发现Li1.4Ti1.7Al0.3Si0.1P2.9O12微晶玻璃的析晶活化能为331.146KJ/mol，晶体生长指数为3，表明Li1.4Ti1.7Al0.3Si0.1P2.9O12玻璃的成核以三维体积成核为主。
[Abstract]:Lithium air batteries have attracted much attention because of their high energy density. Traditional lithium air batteries are easily corroded by water and carbon dioxide in the air due to the use of only organic electrolyte. The cycle performance and stability of lithium air battery are limited. A new type of lithium air battery made of solid electrolyte has become a breakthrough in improving the cycle performance of lithium air battery. Therefore, the preparation of solid electrolyte with high ionic conductivity is the key to improve the performance of lithium air battery. In this paper, Li-ion solid electrolyte Li1.3Al0.3Ti1.7 (PO4) 3) was chosen as the research object. The effects of different preparation process and additive doping on the ionic conductivity and mechanical properties of LATP lithium ion solid electrolyte were discussed. The optimum stoichiometric ratio and process conditions for the preparation of LATP lithium ion solid electrolyte were determined. In addition, the lithium air battery was assembled from LATP solid electrolyte, and the structure of the lithium air battery was determined. The cycle performance and stability of lithium air battery were studied. The study on the preparation of LATP lithium ion solid electrolyte by high temperature solid state method shows that the ionic conductivity of LATP solid electrolyte is not obviously improved by lithium phosphate doping, while the ionic conductivity of LATP solid electrolyte can be improved effectively by doping silicon dioxide. In Li1.3 yTi1.7Al0.3SiyP3-yO12O0.2cm3), when the doping amount of Sio _ 2 is y = 0.1, the ionic conductivity of the prepared LATP solid electrolyte is the highest at room temperature, up to 1.1 脳 10 ~ (-4) S / cm ~ (-1). Boric acid doping can effectively reduce the melting temperature of LATP glass and improve the ionic conductivity of LATP solid electrolyte when the boric acid doping is used to prepare LATP glass-ceramics by monolithic crystallization. The prepared LATP solid electrolyte has the highest ionic conductivity at room temperature, reaching 9.91 脳 10 ~ (-5) S cm ~ (-1). Using LATP glass-ceramics as lithium ion solid electrolyte to assemble the lithium-air battery, it was found that the lithium-air battery prepared by using the mixed solution of lithium chloride of 10mol/L and lithium hydroxide of 0.1mol/L as aqueous phase has good cycling performance and stable performance. When charging and discharging with limited capacity of 1mAh, there is no obvious voltage attenuation for 5 cycles. The DTA curves of LATP were analyzed. It was found that the activation energy of crystallization of Li1.4Ti1.7Al0.3Si0.1P2.9O12 glass-ceramics was 331.146 KJ / mol, and the crystal growth index was 3, which indicated that the nucleation of Li1.4Ti1.7Al0.3Si0.1P2.9O12 glass was dominated by three-dimensional volume nucleation.
【学位授予单位】：哈尔滨工业大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TM911.41

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