LI METAL-FREE RECHARGEABLE BATTERIES BASED ON LI1+XMN2O4 CATHODES (O LESS-THAN-OR-EQUAL-TO X LESS-THAN-OR-EQUAL-TO 1) AND CARBON ANODES

We show that the spinel LiMn2O4, can also be used as the cathode in rechargeable rocking-chair batteries based on lithium intercalation anodes (carbon, either graphite or petroleum coke). At room temperature, such cells show promising cycle life, an average open-circuit voltage of 3.7 V and a specific energy of 250 Wh/kg of electrode materials (cathode+ anode). In addition, we report a novel easily reproducible solution technique for synthesizing Li2Mn2O4, at low temperatures (< 100-degrees-C), using LiI as a mild reducing agent. The cycling behavior of rocking-chair cells using this lithiated phase as the starting cathode is presented. Li2Mn2O4 appears to be a promising practical "air stable" Li-bearing cathode for rocking-chair-type rechargeable cells.