Electrochemical performance of all-solid-state lithium secondary batteries using Li4Ti5O12 electrode and Li2S–P2S5 solid electrolytes

All-solid-state Li–In/Li 4 Ti 5 O 12 cells using Li 2 S–P 2 S 5 solid electrolytes were assembled to investigate their electrochemical properties in the wide voltage range of 0–3 V (versus Li). The Li/Li 4 Ti 5 O 12 cells using 1 M LiPF 6 in ethylene carbonate and diethyl carbonate were fabricated for comparison with the all-solid-state cells. The capacity of the all-solid-state cell using the 70Li 2 S·27P 2 S 5 ·3P 2 O 5 (mol%) solid electrolyte decreased with an increase in the current density as well as the cell using the liquid electrolyte. However, the all-solid-state cell was charged and discharged even at a high current density of 10 mA/cm 2 . The all-solid-state cell was cycled at 1.3 mA/cm 2 and retained 90% of the first reversible capacity of about 120 mAh/g after 500 cycles. The all-solid-state cell cycling at 100 °C showed the small overpotential and reversible capacity of about 120 mAh/g at 13 mA/cm 2 .