The electrical and thermal properties of LiTi2(PO4)(3) (LTP) and LTP composite electrolytes were investigated. LTP-LiNO3 composite electrolyte sintered at 900 degrees C revealed high conductivity (approximately 10(-5) S cm(-1) at 25 degrees C), compared with pure LTP sintered at the same temperature. The thermal behavior in the sintering process of pure LTP and LTP composite electrolytes was examined. Consequently, we found that the conductivity of the composite electrolyte was enhanced by partial melting and subsequent solidification of the pellet at around 800 degrees C. This phenomenon was attributed to the coexistence of Li4P2O7 which was a byproduct of the decomposition of LiNO3 and LTP.