Low charge overpotentials in lithium-oxygen batteries based on tetraglyme electrolytes with a limited amount of water.

High charge overpotentials are a great challenge for the realization of lithium-oxygen batteries. Here, we construct a Li-O2 battery system by introducing a limited amount of water into tetraglyme based electrolytes and electrolytic MnO2 (EMD) and Ru supported on Super P as cathodes for Li-O2 batteries. This results in low charge potentials of around 3.2 V, corresponding to overpotentials of 0.24 V, and outstanding rate capability and cycling performance.