Hiromichi Aono

Electrical property and sinterability of LiTi2(PO4)3 mixed with lithium salt (Li3PO4 or Li3BO3)

Abstract A lithium salt (Li 3 PO 4 or Li 3 BO 3 ) was added to LiTi 2 (PO 4 ) 3 to obtain a dense pellet of the phosphate. The porosity of the sintered pellets decreased and the conductivity was enhanced by the utilization of a binder. A maximum conductivity of 3.0 × 10 −4 S·cm −1 at 298 K was obtained for a sample of LiTi 2 (PO 4 ) 3 −0.2Li 3 BO 3 . The activation energy for the lithium migration at grain boundaries was decreased by the addition of lithium salt. The reason for the conductivity enhancement was attributed to a decrease in the activation energy for the lithium migration at the grain boundary and an increase in the contact area between grains. The conductivity of the bulk component was also increased by the enhancement of Li + -ion migration at grain boundaries.

Ionic conductivity and sinterability of lithium titanium phosphate system

Abstract Lithium titanium phosphates mixed with various metal ions of M 3+ (M=Al, Cr, Ga, Fe, Sc, In, Lu, Y, or La), Li 1+ x M x Ti 2− x (PO 4 ) 3 systems, were prepared, and their properties were investigated. The conductiv ity was enhanced and the porosity of the sintered pellets decreased by the partial replacement of Ti 4+ with the M 3+ ion. The porosity was considerably influenced by the ionic radius of the M 3+ ion. The sinterability was greatly related to the increase of lithium concentrations at the grain boundary. The conductivity enhancement by the substitution mainly resulted from the densification of the sintered pellets.

Electrical properties and crystal structure of solid electrolyte based on lithium hafnium phosphate LiHf2(PO4)3

Abstract The electrical properties and the crystal structure were investigated for the ceramic electrolytes based on LiHf 2 (PO 4 ) 3 . The conductivity enhanced by the Li 2 O addition with LiHf 2 (PO 4 ) 3 system and by the increase of x for Li 1+ x M x Hf 2− x (PO 4 ) 3 (M=Cr, Fe, Sc, In, Lu or Y) systems. The P2 1 /n monoclinic phase transformed to NASICON-type R 3 c rhombohedral phase at above 1173 K. The activation energy for Li + ion migration was decreased by the phase transition. The activation energy for bulk component was 0.42 eV for the NASICON-type structure. A maximum conductivity at 298 K is 1.7 × 10 −4 S·cm −1 for the sample of Li 1.2 Fe 0.2 Hf 1.8 (PO 4 ) 3 .