Investigations on pure and Ag doped lithium lanthanum titanate (LLTO) nanocrystalline ceramic electrolytes for rechargeable lithium-ion batteries

Abstract The nano-crystalline Li 0.5 La 0.5 TiO 3 (LLTO) was prepared as an electrolyte material for lithium-ion batteries. The effect of Ag + ion doping in three different concentrations were investigated: Ag 0.1 Li 0.4 La 0.5 TiO 3 , Ag 0.3 Li 0.2 La 0.5 TiO 3 , and Ag 0.5 La 0.5 TiO 3 along with Li 0.5 La 0.5 TiO 3 . The prepared pure and Ag + doped LLTO were subjected for structural, morphological, electrical and optical characterizations. The cubic superlattice structure of LLTO nano-powder was altered due to the Ag + substitution tending towards a tetragonal phase. Increasing Ag + substitution a complete tetragonal phase occurs in Ag 0.5 La 0.5 TiO 3 . The average particle size of the prepared ceramic electrolyte ranged between 80 nm and 120 nm. The photoluminescence study reveals that the LLTO and Ag doped LLTO gives a blue emission peak. The size effect on grain and grain boundary resistance was observed and reported. With Ag + substitution, the conductivity got decreased due to the impedance caused by Ag + ions in the conducting path of Li + ion. Among all the samples, Ag 0.5 La 0.5 TiO 3 shows maximum conductivity of the order of 10 −3 S cm −1 .