【摘要】：隨著社會(huì)經(jīng)濟(jì)的快速發(fā)展,鋰離子電池已廣泛應(yīng)用于各個(gè)方面。在鋰電池大量使用的過程中,由液態(tài)電解質(zhì)引發(fā)的易燃、易爆等安全隱患是目前亟待解決的問題。針對這一問題,人們提出了全固態(tài)鋰離子電池的概念。固體電解質(zhì)是全固態(tài)電池的重要組成部分。其中,具有類石榴石型晶體結(jié)構(gòu)的固體電解質(zhì)Li7La3Zr2O12(簡稱LLZO)具有較高的室溫離子電導(dǎo)率、較好的電化學(xué)和化學(xué)穩(wěn)定性、環(huán)境污染小、易制備、成本低等優(yōu)點(diǎn),是一種很有應(yīng)用前景的固體電解質(zhì)材料。本文以石榴石結(jié)構(gòu)的LLZO固體電解質(zhì)為研究對象,采用溶膠凝膠法分別制備了Mn4+摻雜的LLZO和Mo6+摻雜的LLZO,并使用X射線衍射儀、阿基米德排水法、掃描電子顯微鏡、交流阻抗譜等測試方法對所得樣品進(jìn)行結(jié)構(gòu)及性能表征。主要研究內(nèi)容如下:采用溶膠凝膠法在900℃保溫6h合成粉體Li7La3Zr2-xMnx O12(x=0、0.01、0.03、0.05、0.07),在1115℃保溫3h燒結(jié)得到Li7La3Zr2-xMnxO12(0≤x≤0.07)陶瓷樣品。X射線衍射結(jié)果表明,所有合成的陶瓷樣品均為立方相與四方相的混合相。Li7La3Zr1.97Mn0.03O12陶瓷樣品的相對致密度高達(dá)94%。Li7La3Zr1.97Mn0.03O12的導(dǎo)電性能最優(yōu),總的離子電導(dǎo)率為9.71×10-5S/cm,總鋰離子遷移激活能為0.33eV。采用溶膠凝膠法在750℃保溫6h合成Li7-2xLa3Zr2-xMoxO12(x=0、0.05、0.10、0.20、0.30)粉體,并在1100℃保溫3h燒結(jié)得到Li7-2xLa3Zr2-xMoxO12(0≤x≤0.30)陶瓷樣品。粉末XRD數(shù)據(jù)表明x≥0.10時(shí),粉體在750℃保溫6h生成立方相結(jié)構(gòu)。陶瓷樣品測得的XRD數(shù)據(jù)結(jié)果顯示,未摻雜的LLZO呈立方相與四方相的混合相結(jié)構(gòu)。摻雜量x≥0.05時(shí),樣品的晶體結(jié)構(gòu)由混合相轉(zhuǎn)變?yōu)榱⒎较嘟Y(jié)構(gòu)。Mo的摻雜使晶粒尺寸逐漸減小,顆粒大小分布均勻,氣孔減少,陶瓷樣品的致密度增加。摻雜量為x=0.20的樣品的致密度高達(dá)92.8%。摻雜量為x=0.20的樣品導(dǎo)電性能最佳,總的離子電導(dǎo)率為5.09×10-4S/cm,對應(yīng)激活能為0.29eV。相比固相法,溶膠凝膠法在較低的溫度下合成具有立方相結(jié)構(gòu)的Mo摻雜的LLZO并提高其離子電導(dǎo)率。
[Abstract]:With the rapid development of social economy, lithium ion battery has been widely used in various fields. In the process of mass use of lithium-ion batteries, the safety problems such as flammability and explosive caused by liquid electrolytes are urgent problems to be solved. To solve this problem, the concept of all solid state lithium ion battery is proposed. Solid electrolyte is an important part of all solid state battery. Among them, the solid electrolyte Li7La3Zr2O12 (LLZO) with garnet crystal structure has the advantages of high ionic conductivity at room temperature, good electrochemical and chemical stability, low environmental pollution, easy preparation and low cost. It is a promising solid electrolyte material. In this paper, LLZO solid electrolyte with garnet structure was studied. Mn4 doped LLZO and Mo6 doped LLZO, were prepared by sol-gel method. X-ray diffractometer, Archimedes drainage method, scanning electron microscope (SEM) were used. The structure and properties of the samples were characterized by AC impedance spectroscopy. The main contents of the study are as follows: the powder Li7La3Zr2-xMnx O12 was synthesized by sol-gel method at 900 鈩，

本文編號(hào)：2288990