Preparation of High Lithium Ion Conducting Glass-Ceramics by Mechanical Milling

1. 采用机械铣削法制备了Li_2S-P_2S_5、Li_2S-P_2S_5- sis_2和Li_2S-P_2S_5- ges_2体系中不同成分的非晶态材料。这些玻璃状材料的球团样品在25℃时表现出10^<-4> Scm^<-1>的高电导率。结果表明，玻璃状材料的锂离子输运数基本一致，作为固体电解质的势窗大于10 V.2。在230℃左右加热得到的高导电性玻璃陶瓷，其x射线衍射图与Li_<4-x>Ge_<1-x>P_xS_4中高导电性硫代- lisicon II相非常相似，表明在这些体系中，由机械研磨的玻璃粉制成的玻璃陶瓷中形成了硫代- lisicon II类似物。通过对原料元素的MM化，得到了高导电性的微晶玻璃。采用Li_2S、P、s的混合方法成功制备了Li_2S-P_2S_5玻璃样，其性质和结构与Li_2S和P_2S_5制备的玻璃样非常相似。通过加热这种元素衍生的硫化物玻璃得到的微晶玻璃具有与p_2s_5衍生玻璃相似的性能。采用微晶玻璃，以熔融法制备的Li_2S-P_2S_5为电解液，LiCoO_2为正极，铟为负极，构建了电化学电池。该全固态电池具有良好的循环性能，即使在200次循环后，其可逆充放电容量仍保持在100mAhg^<-1>左右。

1. Amorphous materials with various compositions in the systems Li_2S-P_2S_5, Li_2S-P_2S_5-SiS_2, and Li_2S-P_2S_5-GeS_2 were prepared by mechanical milling (MM) of crystalline starting materials in a dry N_2 atmosphere at room temperature. The pelletized samples of these glassy materials exhibited high conductivities in the order of 10^<-4> Scm^<-1> at 25℃. It was found that the transport number of lithium ions of the glassy materials was almost unity and the potential window as solid electrolytes was wider than 10 V.2. Highly conductive glass-ceramics were obtained by the heat treatment under a variety of conditions of the above glassy materials prepared by MM. The glass-ceramics obtained after heating at around 230℃ showed the X-ray diffraction patterns very similar to those of highly conductive thio-LISICON II phases in Li_<4-x>Ge_<1-x>P_xS_4, suggesting that the thio-LISICON II analogue is formed in the glass-ceramics derived from the mechanically milled glassy powder in these systems.3. The highly conductive glass-ceramics were also obtained by the MM of starting materials of elements. Glassy Li_2S-P_2S_5 samples were successfully prepared by the MM of Li_2S, P, and S. The properties and structure of the glassy samples are very similar those of the samples prepared using Li_2S and P_2S_5. The glass-ceramics obtained by the heating of such an element-derived sulfide glasses exhibited similar properties to the glass-ceramics from P_2S_5-derived glasses.4. Electrochemical cells were constructed using glass-ceramics in the system Li_2S-P_2S_5 obtained by MM and heat treatment as an electrolyte, LiCoO_2, as a positive electrode and indium as a negative electrode. The all-solid-state cell exhibited excellent cycling performances with the reversible charge-discharge capacities of about 100mAhg^<-1> even after 200 cycles.