Research Institute of Electrochemical Energy, Department of Energy and Environment, National Institute of Advanced Industrial Science and Technology (AIST) , 1-8-31 Midorigaoka, Ikeda, Osaka 563-8577, Japan.
Office of Society-Academia Collaboration for Innovation, Kyoto University , Gokasho, Uji, Kyoto 611-0011, Japan.
J Am Chem Soc. 2017 Jul 5;139(26):8796-8799. doi: 10.1021/jacs.7b03909. Epub 2017 Jun 26.
A unique charge/discharge mechanism of amorphous TiS is reported. Amorphous transition metal polysulfide electrodes exhibit anomalous charge/discharge performance and should have a unique charge/discharge mechanism: neither the typical intercalation/deintercalation mechanism nor the conversion-type one, but a mixture of the two. Analyzing the mechanism of such electrodes has been a challenge because fewer tools are available to examine the "amorphous" structure. It is revealed that the electrode undergoes two distinct structural changes: (i) the deformation and formation of S-S disulfide bonds and (ii) changes in the coordination number of titanium. These structural changes proceed continuously and concertedly for Li insertion/extraction. The results of this study provide a novel and unique model of amorphous electrode materials with significantly larger capacities.
报道了一种非晶态 TiS 的独特充放电机制。非晶态过渡金属多硫化物电极表现出异常的充放电性能，应该具有独特的充放电机制：既不是典型的插层/脱插层机制，也不是转化型机制，而是两者的混合。分析这种电极的机制一直是一个挑战，因为可用的工具较少来检查“非晶态”结构。研究表明，电极经历了两个明显的结构变化：（i）S-S 二硫化物键的变形和形成，以及（ii）钛配位数的变化。这些结构变化在 Li 的插入/提取过程中连续而协同地进行。这项研究的结果提供了一种具有显著更大容量的新型独特的非晶态电极材料模型。
