Several lithium borates (Salt A and Salt B) and a lithium aluminate (Salt C) with electron-withdrawing groups, -OC6F5, -OCOCF3 or -N(SO2CF3)(2), and oligoether chains (-O(CH2CH2O)(n)CH3) directly bonded to the ate complex center, B or Al, were prepared. Lithium borate and lithium aluminate were mixed to get mix-salt electrolytes. Higher ionic conductivity was observed for the mix-salt than for the pure-salt. Conductivity as high as 1.1 X 10(-4) S/cm at ambient temperature (25degreesC) was achieved for the electrolyte in the optimized composition. The reason for such mixing effect on enhancement of ionic conductivity was discussed. Other electrochemical properties including electrochemical stability. compatibility with lithium anode and cyclic performance were also investigated for the mix-salt electrolytes. (C) 2004 Elsevier Ltd. All rights reserved.