WPI Advanced Institute for Materials Research, Tohoku University, Sendai, 980-8577, Japan.
State Key Laboratory of Metal Matrix Composites, School of Materials Science and Engineering, Shanghai Jiao Tong University, Shanghai, 200030, P. R. China.
Adv Mater. 2017 Nov;29(41). doi: 10.1002/adma.201702752. Epub 2017 Sep 11.
Operando scanning transmission electron microscopy observations of cathodic reactions in a liquid-cell Li-O microbattery in the presence of the redox mediator tetrathiafulvalene (TTF) in 1.0 m LiClO dissolved dimethyl sulfoxide electrolyte are reported. It is found that the TTF addition does not obviously affect the discharge reaction for the formation of a solid Li O phase. The coarsening of Li O nanoparticles occurs via both conventional Ostwald ripening and nonclassical crystallization by particle attachment. During charging, the oxidation reaction at significantly reduced charge potentials mainly takes place at Li O /electrolyte interfaces and has obvious correspondence with the oxidized TTF distributions in the electric fields of the charged electrode. This study provides direct evidence that TTF truly plays a role in promoting the decomposition of Li O as a soluble charge-transfer agent between the electrode and the Li O .
本文报道了在 1.0 m LiClO4 溶解于二甲基亚砜电解液的液态 Li-O2 微电池中，添加氧化还原介体四硫富瓦烯（TTF）后，阴极反应的在位扫描透射电子显微镜观察结果。结果表明，TTF 的添加并没有明显影响形成固态 Li2O 相的放电反应。Li2O 纳米颗粒的粗化通过传统的奥斯特瓦尔德熟化和非经典的颗粒附着结晶来进行。在充电过程中，在明显降低的充电电位下，氧化反应主要发生在 Li2O/电解质界面处，并且与充电电极电场中氧化 TTF 的分布具有明显的对应关系。本研究提供了直接证据，证明 TTF 确实作为电极和 Li2O 之间的可溶性电荷转移剂，在促进 Li2O 的分解方面发挥了作用。
