Aqueous lithium-ion battery of Li4Ti5O12/LiMn2O4 using a lithium-ion conductive solid electrolytes separator

Abstract This study investigated the electrochemical properties and performance of an aqueous lithium-ion battery of Li4Ti5O12/LiMn2O4 (LTO/LMO) using a lithium-ion conductive solid electrolyte (SE) composed of NASICON-type Li–Al–Ti–P–O glass ceramic as a separator and a high concentration LiCl-based aqueous electrolyte in order to enhance charge-discharge and cycle life performance. The evolution of H2 gas at the LTO anode during charging was found to be kinetically suppressed by using the SE separator and Zn coating on the LTO anode. As a result, the amount of H2 gas was less than 2.6% that of the porous separator. The SE separator enabled the aqueous electrolyte on the LMO cathode and LTO anode sides to maintain an acidic and a basic solution, respectively, which widened the electrochemical window. Aqueous LTO/LMO batteries using the SE separator exhibited an average voltage of 2.4 V and a high anode capacity of 170 mAh g−1 during charge-discharge cycling test at a rate of 1 C between 2.1 and 2.6 V. It was demonstrated that the battery using a Li2SO4-based aqueous electrolyte in the LMO cathode had good cycle performance and maintained a high coulombic efficiency of 99% after 100cycles.