制备条件对共沉淀法制备铝镁双掺杂锂镧锆氧的影响

Effect of Preparation Conditions on Preparing the Al-Mg Double-Doped Lithium Lanthanum Zirconium Oxide Using Coprecipitation Method

创新提出采用共沉淀法制备石榴石结构锂离子电池无机固态电解质——铝镁双掺杂锂镧锆氧(Li_(6.4)Al_(0.2)La_(3)Zr_(2-0.5x)Mg_(x)O_(12))。利用热重分析(TG)、差示扫描量热仪(DSC)、X射线衍射(XRD)分析试样前驱体在加热过程中的组成和相变,考察最佳烧结温度、烧结时间以及镁掺杂量x,并延伸分析锂离子导电性与温度之间的依赖性。研究发现:1)烧结温度达到630℃时可形成锂镧锆氧;2)最佳烧结温度是1100℃,最佳烧结时间是6 h;3)当镁掺杂量x为0.1时,制备的Li_(6.4)Al_(0.2)La_(3)Zr_(1.95)Mg_(0.1)O_(12);在室温25℃下的离子电导率为1.93×10^(-4)S/cm,活化能为0.271 eV。制备得到了具有最完整立方晶体结构、最少杂质相、最大致密度、最小界面电阻、最高离子电导率和最光滑完整表面形貌的铝镁双掺杂锂镧锆氧。

An innovative coprecipitation method was proposed to prepare inorganic solid electrolyte of garnet-structure lithium-ion battery:Al-Mg double-doped lithium lanthanum zirconium oxide(Li_(6.4)Al_(0.2)La_(3)Zr_(2-0.5x)Mg_(x)O_(12)).Thermogravimetric analysis(TG),differential scanning calorimeter(DSC)and X-ray diffraction(XRD)were used to analyze the composition and phase transition of the sample precursor during heating.The optimum sintering temperature,sintering time and magnesium doping amount x were investigated,and the dependence between lithium-ion conductivity and temperature was further analyzed.Findings:1)When the sintering temperature reaches 630℃,lithium lanthanum zirconium oxide can be formed;2)The best sintering temperature is 1100℃and the best sintering time is 6 h;3)When the magnesium doping amount x is 0.1,the ionic conductivity of prepared Li_(6.4)Al_(0.2)La_(3)Zr_(1.95)Mg_(0.1)O_(12) at room temperature of 25℃is 1.93×10^(-4)S/cm,and the activation energy is 0.271 eV.The Al-Mg double-doped lithium lanthanum zirconium oxide with the most complete cubic crystal structure,the least impurity phase,the largest approximate density,the smallest interface resistance,the highest ionic conductivity and the smoothest and complete surface morphology is prepared.