Dense lithium lanthanum titanate, (Li,La)TiO3, Pellets were prepared using a spark-plasma sintering (SPS) method. The obtained (Li,La)TiO3 pellets showed relatively high lithium ion conductivity, typically 10(-3) S cm(-1) at 22 degreesC, with an activation energy of 30.1 kJ mol(-1). Lithium manganese oxide, LiMn2O4, was deposited on (Li,La)TiO3 pellets by an electrostatic spray deposition (ESD) method at 400 degreesC without significant formation of by-products at the interface (Li,La)TiO3/ LiMn2O4. An all-solid-state battery system, LiMn2O4/(Li,La)TiO3/SPE/Li, where a solid polymer electrolyte (SPE) was sandwiched between (Li,La)TiO3 and Li, showed good charge/discharge characteristics over 100 cycles at 60 degreesC. (C) 2002 Elsevier Science B.V. All rights reserved.