Singlet Oxygen Formation during the Charging Process of an Aprotic Lithium–Oxygen Battery

Abstract

Aprotic lithium-oxygen (Li-O 2 )b atteries have attracted considerable attention in recent years owing to their outstanding theoretical energy density.Am ajor challenge is their poor reversibility caused by degradation reactions,which mainly occur during battery charge and are still poorly understood. Herein, we showt hat singlet oxygen ( 1 D g )i s formed upon Li 2 O 2 oxidation at potentials above 3.5 V. Singlet oxygen was detected through areaction with aspin trap to form as table radical that was observed by time-and voltageresolved in operando EPR spectroscopyi nap urpose-built spectroelectrochemical cell. According to our estimate,alower limit of approximately 0.5 %o ft he evolved oxygen is singlet oxygen. The occurrence of highly reactive singlet oxygen might be the long-overlooked missing link in the understanding of the electrolyte degradation and carbon corrosion reactions that occur during the charging of Li-O 2 cells.

Organic hydrogen peroxide-driven low charge potentials for high-performance lithium-oxygen batteries with carbon cathodes

“…Upon charge, the potential will be too high to decompose Li 2 O 2 (>4.2 V)10. This may trigger the severe oxidative deterioration of the electrolyte and shorten the cycle life of the battery1112. Such problems have blocked the realization of practical Li-air batteries.…”

Structure Design and Composition Engineering of Carbon‐Based Nanomaterials for Lithium Energy Storage

“…Carbon‐based nanomaterials have shown great advantages for Li–O 2 batteries, but an onset of carbon corrosion as low as 3.5 V brings another major problem . Dangling bonds, polymer binders, and oxygen‐containing surface groups of those carbon‐based materials facilitate the generation of reactive species and by‐products during battery operation.…”

Unraveling the Mechanism of the Solution‐Mediated Oxygen Reduction in Metal‐O2 Batteries: The Importance of Ion Association

“…The received values are summarized in Table 1, and in good agreement with previously reported values. [37,38,40] Table 1 also shows the diffusion 4 in TEGDME was used as an electrolyte. The red transients the electrolyte contained 5.6 mM of DBBQ À .…”

“…Unfortunately, this technology is facing many challenges: During charge and discharge, reactive oxygen species like singlet oxygen and superoxide are formed, which are leading to side reactions with carbon electrodes and the electrolyte. [1][2][3][4][5][6] Moreover, the main discharge products in LiÀ O 2 , NaÀ O 2 , KÀ O 2 and MgÀ O 2 batteries are Li 2 O 2 , NaO 2 , KO 2 and MgO 2 , which are electronically insulating. [7][8][9][10][11][12][13][14][15] For the electrochemical deposition of Li 2 O 2 , Bondue et.…”