A Spectroelectrochemical Study of Oxygen Electrode Reactions in Dimethyl Sulfoxide Electrolyte for Aprotic Li-O2 Batteries

Due to their high theoretical energy density, Li-O₂ systems based on aprotic electrolytes have attracted a great deal of interest in the past few years.^1-3 Operation of an aprotic Li-O₂ battery critically relies on the reversible and efficient oxygen electrode reactions occuring in the positive electrode.^4,5 Therefore, it is important to understand the oxygen reaction mechanisms at the positive electrode/Li⁺ electrolyte interface. Here, we report a mechanistic study of a model system, i.e., oxygen reactions on an Au electrode in a Li⁺dimethyl sulfoxide (DMSO) electrolyte with a range of complementary techniques. By spectroscopically identifying the reaction products and intermediates, coupled with electrochemical measurements under well-defined conditions, oxygen reaction pathways and the rate limiting steps were depicted.

References

[1] Bruce, P. G.; Freunberger, S. A.; Hardwick, L. J.; Tarascon, J.-M. Nat. Mater. 2012, 11,  19-29.

[2] Lu, J.; Li, L.; Park, J.-B.; Sun, Y. -K.; Wu, F.; Amine, K. Chem. Rev. 2014, 114, 5611-5640.

[3] Luntz, A. C.; McCloskey, B. D. Chem. Rev. 2014, 114, 11721–11750.

[4] Peng, Z.Q.; Freunberger, S. A.; Chen, Y.; Bruce, P. G. Science 2012, 337, 563-566.

[5] Peng, Z.Q.; Zhang, X.M.; Zhang, Y.L.; Bruce, P.G.  manscirpt in preparation.