Understanding the effect of doping on the charging performance of the Li-O2 battery: the role of hole polarons and lithium vacancies

BARRAL MARIA ANDREA; CARDONA, JHON FABER ZAPATA; CORTES, HENRY A.; VILDOSOLA VERÓNICA

Laussanne

Workshop; Psi-k Worlshop; 2022

In this work, we perform density functional theory calculations using the hybrid functional Heyd?Scuseria?Ernzerhof to properly describe the insulating nature of lithium peroxide andstudy its more energetically favorable surfaces [0001], [1100], and [1120]. We then analyze how the insulating nature and the correct description of the hole polarons at the Li2O2 surfaces affect the electrochemical steps of Li2O2 decomposition in the charging process of Li?O2 batteries. We then study the effect of doping and propose possible scenarios in which ionssuch as Na+ or K+ dissolved in the electrolyte can dope andpromote the generation of Li vacancies in Li2O2 that, in turn,reduce the energy barrier of the limiting steps of Li2O2 decomposition. The origin of this reduction are the lattice distortionsassociated with doping that weaken the surface binding