Stability of the electrolyte toward reduced oxygen species generated at the cathode is a crucial challenge for the rechargeable nonaqueous Li-O-2 battery. Here, we investigate dimethylformamide as the basis of an electrolyte. Although reactions at the O-2 cathode on the first discharge charge cycle are dominated by reversible Li2O2 formation/decomposition, there is also electrolyte decomposition, which increases on cycling. The products of decomposition at the. cathode on discharge are Li2O2, Li2CO3, HCO2Li, CH3CO2Li, NO, H2O, and CO2. Li2CO3 accumulates in the electrode with cycling. The stability of dimethylformamide toward reduced oxygen species is insufficient for its use in the rechargeable nonaqueous Li-O-2 battery.