Recycling application of Li-MnO₂ batteries as rechargeable lithium-air batteries.

The ever-increasing consumption of a huge quantity of lithium batteries, for example, Li-MnO2 cells, raises critical concern about their recycling. We demonstrate herein that decayed Li-MnO2 cells can be further utilized as rechargeable lithium-air cells with admitted oxygen. We further investigated the effects of lithiated manganese dioxide on the electrocatalytic properties of oxygen-reduction and oxygen-evolution reactions (ORR/OER). The catalytic activity was found to be correlated with the composition of Li(x)MnO2 electrodes (0<x<1) generated in situ in aprotic Li-MnO2 cells owing to tuning of the Mn valence and electronic structure. In particular, modestly lithiated Li(0.50)MnO2 exhibited superior performance with enhanced round-trip efficiency (ca. 76%), high cycling ability (190 cycles), and high discharge capacity (10,823 mA h g(carbon)(-1)). The results indicate that the use of depleted Li-MnO2 batteries can be prolonged by their application as rechargeable lithium-air batteries.