I~-的光电化学氧化与光助充电二次锂离子电池

采用扫描电子显微镜、X射线衍射和粉末微电极分别考察了TiO2粉末的形貌、结构以及氧化I-的光电化学行为.结果表明,TiO2粉末晶型为锐钛矿,粒径在100～200 nm范围内.在光照条件下,在TiO2半导体电极上电化学氧化I-生成I2的超电势数值降低约1 V.以TiO2/ITO和Li4Ti5O12分别作为正负极,电解液为碳酸丙烯酯(PC)+LiClO4+LiI,并以聚偏氟乙烯(PVDF)作为隔膜构成分隔式电解池,进行整体电解并结合紫外-可见光谱进行分析.结果表明,该装置在光照条件下电池充电电压比非光照条件下的充电电压降低约0.9 V,且充电效率接近100%.该光电化学装置是一种可以利用光能充电的二次锂离子电池.

Photo-electrooxidiation of I- and Photo-assistant Rechargeable Secondary Li-ion Battery

The structure, micro-morphology, particle size and photo-electrochemical behavior of TiO2 powder in I- contained PC electrolyte were investigated by XRD, SEM and micro-cavity electrode. The results indicate that the size of used TiO2 sample is from 100 nm to 200 nm. The results indicate that the potential of oxidation of I- on anatase-TiO2 is 1 V at irradiation condition, lower than that of oxidation of I- at dark condition. Furthermore, a type of photo-assistant rechargeable Li-ion battery was composed by anatase-TiO2/ITO semi-conductor photo-anode, poly(vinylidene fluoride)(PVDF) membrane and Li4Ti5O12 negative electrode. The charging voltage of such battery is 0.9 V at irradiation condition lower than that of the battery at dark condition. The results of UV-Vis spectroscopy indicate that the charging product of anode half-cell is I2. At the same time, the Li-ion insertion reaction happens on Li4Ti5O12 negative electrode. The total photo-assistant charging reaction of battery is listed as follows: 3LiI+Li4Ti5O12+3hν(3/2)I2+Li7Ti5O12. The results suggest that such batteries can be used as model for the development of next generation photo-assistant rechargeable Li-ion battery.