Li+ Insertion/Extraction Properties for TiNb2O7 Single Particle Characterized by a Particle-Current Collector Integrated Microelectrode
Li+ Insertion/Extraction Properties for TiNb2O7 Single Particle Characterized by a Particle-Current Collector Integrated Microelectrode
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DOI：
10.1149/2.0241903jes
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发表时间：
2018-12-06
影响因子：
3.9
通讯作者：
Sakurai, Yoji
中科院分区：
文献类型：
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作者：
Inada, Ryoji;Kumasaka, Rei;Sakurai, Yoji
在这项研究中，我们使用粒子-电流收集器集成微电极来评价TiNb2O7(TNO)单粒子的电化学性质。在该微电极中，用聚焦离子束处理单元(FIB)通过铂沉积的方法将尺寸约为10微米的TNO单粒子结合在钨微电极的尖端。TNO单粒子的循环伏安曲线在1.6-1.7Vvs.Li/Li+附近出现可逆氧化还原峰。在固定扫描速度下，阳极电流大于阴极电流，表明TNO粒子在Li+提取(即放电)过程中的反应速度快于Li+插入(即充电)过程。这一趋势在充放电容量的C-速率依赖关系中也得到了证实。由恒流间歇滴定测试(GITT)的结果证实，在平衡电位vs.Li/Li+低于1.5V时，Li+在TNO中的表观化学扩散系数在Li+萃取过程中比在Li+插入过程中大得多。此外，经2000次循环后，TNO单颗粒在10C电流下的容量保持率在99%以上，表明TNO单颗粒对Li+的插入和提取反应具有良好的内在稳定性。(C)作者(S)2018年。由ECS出版。
In this study, we evaluate the electrochemical properties of TiNb2O7 (TNO) single particle using a particle-current collector integrated microelectrode, in which TNO single particle with the size of approximately 10 mu m was bonded on the tip of a tungsten microelectrode by platinum deposition using a focused ion beam process unit (FIB). Cyclic voltammogram of TNO single particle showed the reversible redox peaks at around 1.6-1.7 V vs. Li/Li+. Anodic peak current is higher than cathodic one at a fixed scan rate, indicating faster reaction during Li+ extraction (i.e. discharge) than Li+ insertion (i.e. charge) of TNO particle. This tendency was also confirmed in C-rate dependence of charge and discharge capacities. From the results for galvanostatic intermittent titration testing (GITT), we confirmed that at the equilibrium potential vs. Li/ Li+ below 1.5 V, apparent chemical diffusion coefficient of Li+ in TNO at Li+ extraction process is much larger than at Li+ insertion process. Furthermore, the capacity retention of TNO single particle tested at current of 10C after 2000 cycles was above 99%, indicating excellent intrinsic stability of TNO single particle for Li+ insertion and extraction reaction. (C) The Author(s) 2018. Published by ECS.