Synthesis and Electrochemical Properties of Quaternary and Quinary γ-Li3PO4-Type Materials: Effects of Compositional Complexity in Lithium Superionic Conductors

Considering the compositionalcomplexity concept, novel solid electrolytesbased on quaternary and quinary lithium superionic conductor (LISICON)systems were investigated for the development of highly ion-conductingmaterials. Phase identification indicated that even in highly complexcompositions, relatively large Ti- and Ga-doping contents were difficultto achieve in the gamma-Li3PO4 framework.Relatively low ionic conductivities (10(-7) to 10(-5) S cm(-1)) and high activation energies(0.44-0.53 eV) were confirmed compared to ternary LISICON systems,indicating a negligible positive effect of the compositional complexity.In addition, undesirable anti-site disorder occurred in the LISICONcrystal, which was considered to limit fast ion conduction in thequaternary and quinary LISICON systems. A further systematic and detailedstudy is therefore required to accurately determine the effects ofcompositional complexity in the design of fast ion conductors.

Automated summary

Considering the concept of compositional complexity, new solid electrolytes based on quaternary and quinary lithium superionic conductor (LISICON) systems were investigated for highly ion-conducting material development. The study found that even in highly complex compositions, it was difficult to achieve high Ti- and Ga-doping contents in the gamma-Li3PO4 framework. The relatively low ionic conductivities and high activation energies of the quaternary and quinary LISICON systems compared to the ternary LISICON systems indicated a negligible positive effect of the compositional complexity.