Development of sputtered nitrogen-doped Li1+xAlxGe2-x(PO4)3 thin films for solid state batteries

Nitrogen-doped Li1+xAlxGe2-x(PO4)3 (LAGP) thin films were prepared by magnetron sputtering in a mixture of Ar + N2 using an LAGP powder target. The as-deposited amorphous, but could be crystallised into the NASICON phase after annealing at temperatures above 550 °C. introduction nitrogen to gas has two effects on deposited films; incorporation low concentration also reduction rate deposition. former leads improvements Li ion conductivity whereas latter can cause porosity and discontinuities limits their application solid state devices. Up 23% first effect is dominant total ionic improves without introducing morphological defects. However if content increased further, decreases measured conductivity. Optimised doping sputtered results conductivities as high 2.3 × 10?4 S cm?1 only 1 ?m thick (2.7 times higher than undoped films) activation energies below 0.38 eV.