Superoxide Anion Disproportionation Induced by Li⁺ and H⁺: Pathways to ¹O₂ Release in Li−O₂ Batteries

Abstract

The Cover Feature illustrates the electronic energies along the Li+‐coordinated disproportionation of superoxide anions, a parasitic reaction that leads to the formation of the detrimental, highly reactive singlet oxygen molecules which limits the rechargeability and efficiency of lithium–O2 (air) batteries. More information can be found in the Article by E. Bodo and co‐workers.

A Computational Study on Halogen/Halide Redox Mediators and Their Role in 1O2 Release in Aprotic Li–O2 Batteries

“…In fact, the application of large voltages provides the chemical energy required for releasing 1 O 2 . A charging voltage of about 3.5–3.6 V vs Li represents a threshold for the release of significant amounts of singlet oxygen, which is formed upon direct, nonmediated oxidation of Li 2 O 2 on carbon-based electrodes. ,− Moreover, RMs can interact with already formed 1 O 2 either by chemical reaction, which progressively destroys the catalytic amount of the mediator, or by physical quenching. In the latter case, singlet oxygen gets deactivated to the triplet state without affecting the chemical nature of the RM.…”

Study of the Electronic Structure of Alkali Peroxides and Their Role in the Chemistry of Metal–Oxygen Batteries

“… 10 , 11 Despite its simplicity, reactions such as R1 hide a very complex mechanism that involves singlet–triplet spin intersystem crossing while evolving from two doublet LiO 2 radicals. 12 − 14 Due to the coexistence of electronic states of different multiplicities, the disproportionation product can be either 1 O 2 (singlet oxygen) or 3 O 2 (triplet, ground-state oxygen). 15 , 16 The formation of singlet oxygen, which is a highly reactive biradical molecule, is at the origin of parasitic degradation reactions during electrochemical charge/discharge cycles.…”

“… 27 In a previous work, we have explored the superoxide disproportionation reaction when catalyzed by protons or Li ions using multiconfigurational methods. 14 …”

“…A well-known catalytic agent for this reaction is a proton, which partially neutralizes the negative charge and makes the following reaction very efficient. 14 , 28 , 29 …”