An interface consisting of LiMn2O4 thin-film (1μm thick) electrode and Li1+x Al x Ti2−x (PO4)3-based NASICON-type solid electrolyte (LTP) was prepared by a sol–gel coating method. The submicron-sized pores were involved in the thin film, and the porosity of the film was relatively high. The prepared solid–solid electrochemical interface was evaluated by cyclic voltammetry and galvanostatic charge–discharge test. Two reversible redox peaks were observed at 4.0 and 4.1V versus Li/Li+ in the cyclic voltammogram due to the redox of Mn3+/4+. The LiMn2O4 thin-film electrode on LTP exhibited a discharge capacity of 80mAhg−1 at 0.1C rate.