Mechanistic Study of Solvent-Mediated Oxygen Reduction Reaction/Oxygen Evolution Reaction for Li-Air Battery Applications

Li-air batteries (LABs) have drawn growing interest toreplaceLi-ion batteries due to their extremely high theoretical energy density.However, the development of LABs is restricted majorly to designingair-cathode electrocatalysts and studying electrolyte properties suchas conductivity and stability. Determining the effect of the explicitsolvent environment on the electrochemical reactions taking placein LABs is important. Here, we have carried out the first principlesthermodynamic study for LAB reactions (discharge and charge) on theLi(2)O(2)(100) cathode surface considering the effectof explicit dimethyl sulfoxide (DMSO) solvent. The mechanistic pathwaysand the thermodynamic overpotentials of LAB reactions are investigated.Furthermore, the effect of the explicit DMSO environment on the configurationsof intermediate adsorptions resulting in changes in free energiesis analyzed. The toroid-like nature of subsequent Li2O2 growth in the considered model is also proposed. An improvedoverpotential of discharging (0.52 V) for the considered system isreported, signifying the importance of considering the surface-solventinterphase model to study LAB reactions closer to the experimentalscenario.