Electronic changes in poly(3,4-ethylenedioxythiophene)-coated LiFeSO4F during electrochemical lithium extraction
Electronic changes in poly(3,4-ethylenedioxythiophene)-coated LiFeSO4F during electrochemical lithium extraction
复制标题
DOI：
10.1016/j.jpowsour.2019.02.039
复制
发表时间：
2019-04
影响因子：
9.2
通讯作者：
A. Blidberg;M. Valvo;M. Alfredsson;C. Tengstedt;T. Gustafsson;F. Björefors
中科院分区：
文献类型：
--
作者：
A. Blidberg;M. Valvo;M. Alfredsson;C. Tengstedt;T. Gustafsson;F. Björefors
用多种光谱技术研究了包覆聚(3，4-乙二氧基噻吩基)的LiFeSO4F的氧化还原活性。通过X射线吸收光谱研究了LiFeSO4F-PEDOT复合材料脱氢后的电子变化和铁-配体氧化还原特性。PEDOT涂层在电池循环所用的电压窗口内是电化学稳定的，在这里获得足够的导电性是发生LiFeSO4F电化学反应所必需的。尽管在Li半电池中电化学处理后，PEDOT的电子构型也出现了一些相应的还原和氧化形式的变化，但在最初的几个循环中，它的p型掺杂完全保持在Li+/Li的2.7V4.1 V之间。在锂的电化学萃取过程中，LixFeSO4F中的铁-配体相互作用增强，这似乎是多阴离子插入化合物的一个总的趋势。这一发现对于深入了解锂离子电池正极材料中的一系列氧化现象是至关重要的，并为探索具有更高电化学性能的新型储能材料铺平了道路。
The redox activity oftavoriteLiFeSO4F coated with poly (3,4-ethylenedioxythiophene), i.e. PEDOT, is investigated by means of several spectroscopic techniques. The electronic changes and iron-ligand redox features of this LiFeSO4F-PEDOT composite are probed upon delithiation through X-ray absorption spectroscopy. The PEDOT coating, which is necessary here to obtain enough electrical conductivity for the electrochemical reactions of LiFeSO4F to occur, is electrochemically stable within the voltage window employed for cell cycling. Although the electronic configuration of PEDOT shows also some changes in correspondence of its reduced and oxidized forms after electrochemical conditioning in Li half-cells, its p-type doping is fully retained between 2.7 and 4.1 V with respect to Li+/Li during the first few cycles. An increased iron-ligand interaction is observed in LixFeSO4F during electrochemical lithium extraction, which appears to be a general trend for polyanionic insertion compounds. This finding is crucial for a deeper understanding of a series of oxidation phenomena in Li-ion battery cathode materials and helps paving the way to the exploration of new energy storage materials with improved electrochemical performances.