Rare-Earth Metal Doping into Lithium Stuffed Garnet-Type Electrolytes for Next Generation, Solid State, Lithium Ion Batteries

Lithium stuffed garnet-type materials are promising candidates for solid state electrolytes to be used in next generation, all solid state, lithium ion batteries. However, despite significant work, there are still issues to solve, such as improving the conductivity, preventing Li dendrite growth, and reducing the electrolyte/electrode interfacial resistance. There is consequently a need to investigate additional doping strategies in these garnet materials. This work investigates doping a variety of rare-earth metals into the garnet type Li 5+y La 3 (Nb/Ta) 2-x Ln x O 12 (Ln = rare earth metal, 0 > x = < 2), in order to both increase the Li content and the unit cell size, so as to enhance the Li ion conductivity. We also investigate the effect of this doping strategy on the reaction with moisture. The possible incorporation of such dopants into the high Li content Li 7 La 3 (Zr/Hf) 2 O 12 systems is also investigated.