All-solid-state Li-In/Li4Ti5O12 cells using the 80Li(2)S center dot 20P(2)S(5) solid electrolyte were assembled to investigate their rate performances and impedance behaviors. Furthermore, Li/Li4Ti5O12 cells using 1 mol dm(-3) LiPF6 dissolved in ethylene carbonate and diethyl carbonate were fabricated for comparison to the all-solid-state cells. In the all-solid-state cells, resistance attributable to the lithium-ion transfer from the solid electrolyte to Li4Ti5O12 spinel phase was observed during the lithium insertion into Li4Ti5O12 spinel phase during the discharge process. Results clarified that the cells using the solid electrolyte showed higher resistance and larger activation energy for this lithium-ion transfer than the cells using the liquid electrolyte. Resistance was not observed in the charge process. The all-solid-state cell showed the average charge voltage of 1.9 V (vs Li) and reversible capacity of similar to 80 mAh g(-1) at the charge current density of 1.3 mA cm(-2) and the discharge current density of 0.064 mA cm(-2).