Mo3Nb2O14: A high-rate intercalation electrode material for Li-ion batteries with liquid and garnet based hybrid solid electrolytes

Herein we report Mo3Nb2O14 possessing a layered open framework structure as potential candidate for Li-ion batteries with conventional liquid electrolyte as well as with a hybrid solid electrolyte (garnet oxide-ionic liquid). The material delivers a discharge capacity of 329 mA h g(-1) at 1C rate in a liquid electrolyte-based cell, corresponding to insertion of 8.5 Li. Moreover, it exhibits excellent rate capability (up to 50C rate) and good capacity retention. Considering the high capacity and high rate capabilities of the material we further investigate its performance in presence of garnet based quasi (hybrid) solid electrolyte owing to the attractive features of solid-state batteries. When hybrid solid electrolyte is used, the electrode material delivers an initial discharge capacity of 206 mA h g(-1) at high current rate of 1C and exhibits excellent capacity retention of 165 mA h g(-1) (80%) at the end of 100 charge-discharge cycles. The ultra-fast Li+ insertion/extraction can be attributed to the three-dimensional channel structure of the Mo3Nb2O14 which allows facile lithium ion transport. Hence, this work supports the idea of revisiting layered type metal oxides as electrodes for developing high energy density and safe lithium ion batteries.