The low ionic conductivity was a bottleneck in inorganic solid state electrolytes used for lithium ion batteries. In ceramic electrolytes, grain boundary usually dominates the total conductivity. In order to improve the grain boundary effect, an amorphous silica layer was introduced into the grain boundaries of ceramic electrolytes based upon lithium–lanthanum–titanate, as evidenced by electron microscopy. The results showed that the total ionic conductivity could be enhanced to over 10−4S/cm at room temperature. This could be attributed to removing the anisotropy of outer-shell of grains, supplement of lithium ions in various sites in the grain boundary and close binding among grains aided by the amorphous boundary.

Role of Amorphous Boundary Layer in Enhancing Ionic Conductivity of Lithium–Lanthanum–Titanate Electrolyte. A.Mei, X.L.Wang, J.L.Lan, Y.C.Feng, H.X.Geng, Y.H.Lin, C.W.Nan: Electrochimica Acta, 2010, 55[8], 2958-63