The Decisive Role of Li2O2 Desorption for Oxygen Reduction Reaction in Li–O2 Batteries,ACS Energy Letters

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The Decisive Role of Li2O2 Desorption for Oxygen Reduction Reaction in Li–O2 Batteries
ACS Energy Letters ( IF 19.3 ) Pub Date : 2023-02-03 , DOI: 10.1021/acsenergylett.2c02714
Chengyang Xu _{1,

2} , Aimin Ge ₂ , Koki Kannari ₂ , Baoxu Peng ₂ , Min Xue ₁ , Bing Ding ₁ , Ken-ichi Inoue ₂ , Xiaogang Zhang ₁ , Shen Ye _{2,

3}

Affiliation

Fundamental issues relevant to the oxygen reduction reaction (ORR) mechanism and reaction interface are ambiguous in Li–O₂ batteries. Herein, we utilized highly sensitive surface-enhanced Raman spectroscopy (SERS) to reveal the spontaneous desorption behavior of insoluble products of lithium peroxide (Li₂O₂) from the electrode surface. Furthermore, the electrochemical ORR mechanism is elucidated at the electrode/Li₂O₂ interface based on a dynamic equilibrium between the generation and desorption of Li₂O₂. The desorption of adsorbed Li₂O₂ species (Li₂O₂*) is crucial to releasing surface sites and maintaining the electrochemical ORR process at the electrode substrate surface instead of the Li₂O₂/electrolyte interface. The proceeding of Li₂O₂* desorption can guarantee the stability of Li₂O₂* concentration and the discharge plateau in the galvanostatic ORR process. The suppression of Li₂O₂* desorption is proved to induce the termination of Li₂O₂* generation, which is accompanied by the growth of adsorbed lithium superoxide (LiO₂*), leading to rapid potential attenuation.

中文翻译：

Li2O2 脱附对 Li-O2 电池中氧还原反应的决定性作用

_{在 Li-O 2}电池中，与氧还原反应 (ORR) 机制和反应界面相关的基本问题尚不明确。在此，我们利用高灵敏度表面增强拉曼光谱 (SERS) 来揭示过氧化锂 (Li ₂ O ₂ ) 不溶性产物从电极表面的自发解吸行为。_{此外，基于 Li 2} O ₂的生成和解吸之间的动态平衡，在电极/Li 2 O 2 界面阐明了_电化学ORR_机制。吸附的 Li ₂ O ₂物种（Li ₂ O ₂*) 对于释放表面位点和维持电极基底表面而非 Li ₂ O ₂ /电解质界面处的电化学 ORR 过程至关重要。_{Li 2} O ₂ * 脱附的进行可以保证恒流ORR过程中Li ₂ O ₂ * 浓度的稳定和放电平台。_{Li 2} O ₂ * 解吸的抑制被证明可诱导Li ₂ O ₂ * 生成的终止，伴随着吸附的超氧化锂（LiO ₂ *）的生长，导致电位快速衰减。

更新日期：2023-02-03

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