本文關鍵詞：全固態(tài)鋰離子電池硫化物電解質的制備和性能研究　出處：《天津大學》2015年碩士論文　論文類型：學位論文

  更多相關文章： 全固態(tài)鋰離子電池 硫化物固體電解質 離子電導率 化學穩(wěn)定性 循環(huán)效率

【摘要】：鋰離子電池作為動力電源已經廣泛地應用于移動電子設備、混合型電子設備和分布式能源系統(tǒng)中。但是,由于傳統(tǒng)的鋰離子電池使用的是易燃的液體電解質,所以存在易燃、易泄漏、易腐蝕等安全隱患。隨著高功率動力型鋰離子電池的市場需求不斷增長,人們對鋰離子電池的能量密度的要求越來越高,導致鋰離子電池的安全性問題越來越突出。全固態(tài)電池是一類以固體電解質取代傳統(tǒng)液態(tài)電解質的新型高安全性鋰離子電池,其電解質主要分為聚合物固態(tài)電解質和無機固態(tài)電解質。其中,由于具有更高的安全性,無機固體電解質得到了廣泛的關注和快速的發(fā)展。無機固體電解質存在的主要缺點是離子電導率低,尚不能滿足動力電池大電流放電的需要,因此提高離子電導率是無機固體電解質走向工業(yè)化應用的一個關鍵。目前Li_2S-P_2S_5體系硫化物固體電解質被認為是實現(xiàn)鋰離子電池全固體化的最佳電解質材料之一,具有離子電導率高,電子電導率低,活化能小,機械強度高等優(yōu)點,正成為國內外化學電源領域的一個研究熱點。本文綜述了全固態(tài)鋰離子電池和硫化物固體電解質的最近研究進展,對Li_2S-P_2S_5基硫化物固體電解質進行了分類介紹,探討了它們在實際應用中所存在的一些問題。采用機械研磨技術分別制備了二元Li_2S-P_2S_5、三元95(0.7Li_2S 0.3P_2S_5) 5Li_3PO_4和四元69Li_2S 26P_2S_5 3P_2O_5 2FeS硫化物玻璃態(tài)電解質,并組裝成全固態(tài)LiCoO_2/Li鋰離子電池。采用X射線衍射、差示掃描量熱法、交流阻抗、循環(huán)伏安、掃描電子顯微鏡、透射電子顯微鏡恒電流充放電等測試手段對所制備的硫化物固體電解質和全固態(tài)電池性能進行了表征和測試。實驗結果表明,所制備的三種硫化物電解質的在100℃時的電導率均在10-3 S cm-1以上,電化學窗口均能達到5V。電解質與金屬Li負極相容性很好。通過溶膠-凝膠法對LiCoO_2表面進行包覆改性,分別包覆了Nb_2O_5、TiO_2、ZrO_2,包覆量在5 wt%左右。實驗發(fā)現(xiàn),包覆改性可以顯著提高全固態(tài)鋰離子電池的放電容量和放電平臺電壓。充放電測試結果顯示,100℃時,全固態(tài)電池Li/SE/LiCoO_2的放電容量最高可達150 mAh g-1,循環(huán)50圈后的效率仍能達到95%以上。
[Abstract]:Lithium ion batteries have been widely used in mobile electronic devices, hybrid electronic devices and distributed energy systems as power supply. However, traditional lithium ion batteries use flammable liquid electrolytes. With the increasing market demand of high-power Li-ion batteries, the energy density of Li-ion batteries is more and more demanding. All solid state battery is a new type of high security lithium ion battery which replaces the traditional liquid electrolyte with solid electrolyte. Its electrolytes are mainly classified into polymer solid electrolyte and inorganic solid electrolyte. Inorganic solid electrolytes have received extensive attention and rapid development. The main shortcoming of inorganic solid electrolytes is the low ionic conductivity, which can not meet the needs of high current discharge of power batteries. Therefore, increasing ionic conductivity is a key to the industrial application of inorganic solid electrolytes. At present, sulphide solid electrolytes in Li_2S-P_2S_5 system are considered to be fully solid for lithium-ion batteries. One of the best electrolyte materials. It has the advantages of high ionic conductivity, low electronic conductivity, low activation energy and high mechanical strength. It is becoming a research hotspot in the field of chemical power supply at home and abroad. This paper reviews the recent research progress of all solid state lithium ion batteries and sulphide solid electrolytes. The classification of solid sulfide electrolytes based on Li_2S-P_2S_5 was introduced. Some problems existed in their practical application were discussed. Binary Li_2S-P_2S_5 was prepared by mechanical grinding technique. Three Yuan 95, 0.7Li2S, 0.3P2S5s _ _ _. Five Li3PO4 and four $69Li2S / 26P\\\'\\\?\\?\\\?\\\? All solid-state LiCoO_2/Li lithium-ion batteries were assembled by X-ray diffraction, differential scanning calorimetry, AC impedance, cyclic voltammetry and scanning electron microscope. The properties of sulfide-solid electrolyte and all-solid-state battery were characterized and tested by transmission electron microscope (TEM), constant current charge-discharge and so on. The conductivity of the three sulphide electrolytes was above 10-3 S cm-1 at 100 鈩，

本文編號：1388001