MATERIALS DESIGN OF CRYSTALLINE LITHIUM IONIC CONDUCTORS WITH FRAMEWORK STRUCTURE

锂超离子导体在远低于熔点的温度下，在其离子亚晶格--可移动离子亚晶格--中表现出高的锂离子扩散。了解它们在“固体”材料中的快速离子传输是非常有意义的，这是一种被广泛认识的现象，尽管仍然相对罕见。陶瓷晶态电解液在全固态锂电池中的应用具有重要的技术意义，可以解决使用非水液态电解液的可充电锂离子电池的安全问题。陶瓷晶态电解液在化学和电化学稳定性方面优于液体、聚合物、凝胶甚至玻璃电解液。合成新的陶瓷锂快离子导体已经做了很多尝试，最高电导率达到了10^&lt；-3&gt；S cm；-1&gt；但是，0.445V的低分解电位限制了它作为锂固体电解质的应用。在Li_2S-GeS_2、Li_2S-GeS_2-ZnS和Li_2S-GeS_2-Ga_2S_3系统中发现的新的锂快离子导体具有与γ-Li_3PO_4型有关的结构。发现了六种新材料(Li_2GeS_3、Li_4GeS_4、Li_2ZnGeS_4、Li_xGt；4-x&gt；Zn_xGeS_4、Li_5GaS_4、Li_&lt；4+x+delta&gt；(Ge_&lt；1-delta‘-x&gt；GaS_x)SS_4)，和LiS_xGt；4+x+Delta&gt；(GeS_3GaS_X))S_4的室温电导率最高，达到6.5×10~(-5)~(-5)~(Gt)；S cm~(-1)~(-1)。我们的电化学测试结果表明，LiS_&lt；4+x+delta&gt；(Ge_&lt；1-delta‘-x&gt；Ga_x)S_4与Li相比，在5V以下是稳定的。

Lithium superionic conductors exhibit high lithium-ionic diffusion in one of their ionic sublattice - the mobile ion sublattice - at temperature well below melting points. It is of great interest to understand their fast-ionic transport in "solid' materials, which is widely recognized, although still relatively rare, phenomenon. They are also of technological importance for future applications as solid electrolyte for all-solid lithium battery and may solve the safety problems of the rechargeable lithium ion battery using non-aqueous liquid electrolytes.Ceramic crystalline electrolytes have advantages over liquid, polymer, gel or even glass electrolytes for their chemical and electrochemical stability. Many attempts to synthesize new ceramic lithium superionic conductors have been made ; the highest conductivity of 10^<-3> S cm^<-1> was previously reported for H-doped Li_3N.However, the low decomposition potential of 0.445V restricts its application as a lithium solid electrolyte. The new thio-LISICON (LIthium SuperIonic CONductor) found in the Li_2S-GeS_2, Li_2S-GeS_2-ZnS, and Li_2S-GeS_2-Ga_2S_3 systems have structures related to the gamma-Li_3PO_4-type. Six new materials were found (Li_2GeS_3, Li_4GeS_4, Li_2ZnGeS_4, Li_<4-x>Zn_xGeS_4, Li_5GaS_4, and Li_<4+x+delta>(Ge_<1-delta'-x>GaS_x)SS_4), and LiS_<4+x+delta>(GeS_3GaS_x)S_4 showed the highest conductivity of 6.5x10^<-5> S cm^<-1> at room temperature. Our results on electrochemical measurements indicated that LiS_<4+x+delta>(Ge_<1-delta'-x>Ga_x)S_4 is stable up to 5V vs. Li.