Chemical vs Electrochemical Formation of Li2CO3 as a Discharge Product in Li–O2/CO2 Batteries by Controlling the Superoxide Intermediate,The Journal of Physical Chemistry Letters

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Chemical vs Electrochemical Formation of Li2CO3 as a Discharge Product in Li–O2/CO2 Batteries by Controlling the Superoxide Intermediate
The Journal of Physical Chemistry Letters ( IF 4.8 ) Pub Date : 2016-12-19 00:00:00 , DOI: 10.1021/acs.jpclett.6b02610
Wei Yin _{1,

2} , Alexis Grimaud _{1,

3} , Florent Lepoivre _{1,

2} , Chunzhen Yang ₁ , Jean Marie Tarascon _{1,

2,

3,

4}

Affiliation

The Li–O₂/CO₂ battery with high capacity has recently been proposed as a new protocol to convert CO₂. However, the fundamental mechanism for the reaction still remains hazy. Here, we investigated the discharge processes of Li–O₂/CO₂ (70%/30%) batteries in two solvents, dimethyl sulfoxide (DMSO) and 1,2-dimethoxyethane (DME). During discharge, both solvents initially show the reduction of oxygen. However, afterward, the solvent affects the reaction pathways of superoxide species by solvating Li⁺ with different strength, depending on the so-called donor number. More precisely, the initial formation of CO₄^•– is favored in DMSO at the expense of lithium superoxide formation that we observed in DME. Despite the different intermediate processes, X-ray diffraction showed that Li₂CO₃ was the final discharge product in both solvents. Moreover, we observed that CO₂ cannot be reduced within the electrochemical stability window of DMSO and DME.

中文翻译：

通过控制超氧化物中间产物在Li–O ₂ / CO ₂电池中放电产物Li ₂ CO _3的化学与电化学形成

高容量的Li–O ₂ / CO ₂电池最近被提出作为转换CO ₂的新协议。但是，反应的基本机理仍然不明确。在这里，我们研究了Li–O ₂ / CO ₂（70％/ 30％）电池在二甲亚砜（DMSO）和1,2-二甲氧基乙烷（DME）两种溶剂中的放电过程。在放电过程中，两种溶剂最初都会显示出氧气的减少。然而，此后，取决于所谓的给体数，溶剂通过使具有不同强度的Li ⁺溶剂化而影响超氧化物类的反应途径。更确切地说，CO ₄^•的初始形成如我们在DME中观察到的那样，在DMSO中偏爱于以形成过氧化锂为代价。尽管中间过程不同，但X射线衍射显示Li ₂ CO ₃是两种溶剂中的最终放电产物。此外，我们观察到在DMSO和DME的电化学稳定性窗口内无法还原CO ₂。

更新日期：2016-12-19

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