Unraveling the Effect of Singlet Oxygen on Metal-O2 Batteries: Strategies Toward Deactivation.

Idoia Ruiz de Larramendi,Nagore Ortiz-Vitoriano

doi:10.3389/fchem.2020.00605

Idoia Ruiz de Larramendi, Nagore Ortiz-Vitoriano

Open Access

https://doi.org/10.3389/fchem.2020.00605

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Abstract

Aprotic metal-O2 batteries have attracted the interest of the research community due to their high theoretical energy density that target them as potential energy storage systems for automotive applications. At present, these devices show various practical problems, which hinder the attainment of the high theoretical energy densities. Among the main limitations, we can highlight the irreversible parasitic reactions that lead to premature death of the battery. The degradation processes, mainly related to the electrolyte, lead to the formation of secondary products that accumulate throughout the cycling in the air electrode. This accumulation of predominantly insulating products results in the blocking of active sites, promoting less efficiency in system performance. Recently, it has been discovered that the superoxide intermediate radical anion is involved in the generation of the reactive oxygen singlet species (1O2) in metal-O2 batteries. The presence of singlet oxygen is intimately linked with electrolyte degradation processes and with carbon-electrode corrosion reactions. This review analyzes the nature of singlet oxygen, while clarifying its toxic role in metal-O2 batteries. Besides, the main mechanisms of deactivation of singlet oxygen are presented, trying to inspire the research community in the development of new molecules capable of mitigating the harmful effects related to this highly reactive species.

Highlights

In a world increasingly concerned with the dire consequences of climate change, the increase in renewable energy generation over the last 20 years offers hope in the struggle to save the planet
This study showed that the controlled presence of water in the electrolyte led to an increase in the battery capacity where larger NaO2 cubes were formed. This effect was attributed to the presence of H+ in H2O that participate in the crystal growth, not as solvation of the superoxide but as proton phase-transfer catalysis (PPTC)
There are a number of challenges that must be overcome before widespread commercialization is possible such as irreversible parasitic reactions

Summary

Unraveling the Effect of Singlet

Reviewed by: Olivier Fontaine, UMR5253 Institut de Chimie Moléculaire et des Matériaux Charles Gerhardt Montpellier (ICGM), France Jianping Huang, Lawrence Berkeley National Laboratory, United States. Aprotic metal-O2 batteries have attracted the interest of the research community due to their high theoretical energy density that target them as potential energy storage systems for automotive applications. At present, these devices show various practical problems, which hinder the attainment of the high theoretical energy densities. The degradation processes, mainly related to the electrolyte, lead to the formation of secondary products that accumulate throughout the cycling in the air electrode. This accumulation of predominantly insulating products results in the blocking of active sites, promoting less efficiency in system performance.

INTRODUCTION

WHAT IS SINGLET OXYGEN?

HOW SINGLET OXYGEN CAN BE DEACTIVATED?

Findings

CONCLUSIONS