Singlet Oxygen Production in the Reaction of Potassium Superoxide with Chlorine

Li, Qingwei; Chen, Fang; Zhao, Weili; Xu, Mingxiu; Fang, Benjie; Zhang, Yuelong; Duo, Liping; Jin, Yuqi; Sang, Fengting

doi:10.1246/cl.2007.496

Cited by 7 publications

(7 citation statements)

References 17 publications

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“…Singlet oxygen (term symbol 1 Δ g , hereafter 1 O 2 ) could potentially be this reactive intermediate . It is a strong oxidizing agent and known to form upon chemical oxidation of Li 2 O 2 , Na 2 O 2 , and a series of organic peroxides . The thermodynamically reversible potential for 1 O 2 evolution during the electrooxidation of Li 2 O 2 can be estimated to be between 3.45 and 3.55 V, only about 0.5 V higher than its reversible potential to triplet oxygen (term symbol 3 ∑ g − ), U 0 =2.96 V .…”

Section: Methodsmentioning

confidence: 99%

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

et al. 2016

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Aprotic lithium-oxygen (Li-O2 ) batteries have attracted considerable attention in recent years owing to their outstanding theoretical energy density. A major challenge is their poor reversibility caused by degradation reactions, which mainly occur during battery charge and are still poorly understood. Herein, we show that singlet oxygen ((1) Δg ) is formed upon Li2 O2 oxidation at potentials above 3.5 V. Singlet oxygen was detected through a reaction with a spin trap to form a stable radical that was observed by time- and voltage-resolved in operando EPR spectroscopy in a purpose-built spectroelectrochemical cell. According to our estimate, a lower limit of approximately 0.5 % of the 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-O2 cells.

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Section: Methodsmentioning

confidence: 99%

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

et al. 2016

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“…[35,37,111] Nevertheless, even with substantial electrolyte and electrode screening efforts, the performance improvement of the Li-O 2 battery so far has been proved fruitless under the guidance of this idea. [112,113] Initially, in the process of studying a chemical oxygen-iodine laser (COIL), Sang et al [114] found that solid inorganic peroxides, such as [21] This hypothesis did not receive enough attention until the work conducted by Gasteiger's group. Pioneering experimental work by Gasteiger's group reported the generation of singlet oxygen during the charging process for the first time at potentials >3.5 V in the Li-O 2 system and demonstrated its critical role in parasitic chemistry.…”

Section: Parasitic Chemistry During Chargingmentioning

confidence: 99%

Understanding the Reaction Chemistry during Charging in Aprotic Lithium–Oxygen Batteries: Existing Problems and Solutions

et al. 2019

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The aprotic lithium-oxygen (Li-O 2 ) battery has excited huge interest due to its having the highest theoretical energy density among the different types of rechargeable battery. The facile achievement of a practical Li-O 2 battery has been proven unrealistic, however. The most significant barrier to progress is the limited understanding of the reaction processes occurring in the battery, especially during the charging process on the positive electrode. Thus, understanding the charging mechanism is of crucial importance to enhance the Li-O 2 battery performance and lifetime. Here, recent progress in understanding the electrochemistry and chemistry related to charging in Li-O 2 batteries is reviewed along with the strategies to address the issues that exist in the charging process at the present stage. The properties of Li 2 O 2 and the mechanisms of Li 2 O 2 oxidation to O 2 on charge are discussed comprehensively, as are the accompanied parasitic chemistries, which are considered as the underlying issues hindering the reversibility of Li-O 2 batteries. Based on the detailed discussion of the charging mechanism, innovative strategies for addressing the issues for the charging process are discussed in detail. This review has profound implications for both a better understanding of charging chemistry and the development of reliable rechargeable Li-O 2 batteries in the future.

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“…Alfano and Christie used Li 2 O 2 and Na 2 O 2 in combination with HCl and HBr, resulting in emissions at 1270 nm . Li et al used Li 2 O 2 , Na 2 O 2 , and KO 2 as starting materials and wetted chlorine gas as an oxidizing agent. , In these cases, emission at 1270, 703, and 634 nm was observed. It can be assumed that the mixing of these superoxides and peroxides will result in the formation of H 2 O 2 , and depending on the conditions, hypochlorous acid (HOCl) or chlorine gas in situ .…”

Section: Background and Literature Reviewmentioning

confidence: 99%

“…Summarizing timeline of the reviewed literature: (a) refs , ; (b) ref ; (c) ref ; (d) refs − ; (e) refs , ; (f) refs − ; (g) ref ; (h) ref ; (i) refs − ; (j) ref ; (k) ref ; (l) ref ; (m) ref ; (n) ref ; (o) ref ; (p) ref ; (q) ref ; (r) ref .…”

Section: Background and Literature Reviewunclassified

Singlet Oxygen in Electrochemical Cells: A Critical Review of Literature and Theory

et al. 2021

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Rechargeable metal/O2 batteries have long been considered a promising future battery technology in automobile and stationary applications. However, they suffer from poor cyclability and rapid degradation. A recent hypothesis is the formation of singlet oxygen (1O2) as the root cause of these issues. Validation, evaluation, and understanding of the formation of 1O2 are therefore essential for improving metal/O2 batteries. We review literature and use Marcus theory to discuss the possibility of singlet oxygen formation in metal/O2 batteries as a product from (electro)chemical reactions. We conclude that experimental evidence is yet not fully conclusive, and side reactions can play a major role in verifying the existence of singlet oxygen. Following an in-depth analysis based on Marcus theory, we conclude that 1O2 can only originate from a chemical step. A direct electrochemical generation, as proposed by others, can be excluded on the basis of theoretical arguments.

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Singlet Oxygen Production in the Reaction of Potassium Superoxide with Chlorine

Cited by 7 publications

References 17 publications

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

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

Understanding the Reaction Chemistry during Charging in Aprotic Lithium–Oxygen Batteries: Existing Problems and Solutions

Singlet Oxygen in Electrochemical Cells: A Critical Review of Literature and Theory

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