基于纳米多孔钛酸锂结构的染料敏化太阳电池复合光阳极研究

Hybrid Photoanodes Based on Nanoporous Lithium Titanate Nanostructures in Dye-sensitized Solar Cells

本研究探索了具有良好导电性能的多孔钛酸锂结构对传统氧化钛纳米晶光阳极的增强效果。以钛酸四丁酯、氢氧化锂为源,采用溶胶-凝胶结合溶剂热反应和高温烧结方法,制备了具有多孔结构的尖晶石型Li4Ti5O12纳米粉体;在表征其结晶性、微观形貌及孔结构的基础上,将其与Ti O2纳米晶浆料复合,制备复合光阳极,并详细考察了钛酸锂掺量、结晶性和孔结构等对电池光电转换性能的影响规律。结果表明:随热处理温度升高,Li4Ti5O12结晶性增强,晶粒尺寸明显增大,比表面积下降。掺入Li4Ti5O12粉体可以有效提高光阳极膜的染料负载量,降低Ti O2/染料分子/电解液界面的电子传输阻抗,从而明显提高复合光阳极的光电流密度(Jsc=13.91 m A/cm2)和开路电压(Voc=0.8 V)。Li4Ti5O12含量为1wt%的复合光阳极电池光电转化效率最好,达到7.011%,比纯Ti O2电池(效率:5.384%)提高30%。

Li4Ti5O12 with nanoporous feature and good conductivity was used to enhance the photoelectrochemical performance of traditional nanocrystalline Ti O2 photoanodes in Dye-sensitized Solar Cells（DSSC）. Using tetrabutyl titanate and lithium hydroxide as raw materials, the spinel Li4Ti5O12 was obtained from common Sol-Gel, solvethermal and annealing processes. The dependence of the crystallinity, morphology and pore structure of the Li4Ti5O12 powders on the annealing temperature were investigated. Li4Ti5O12-Ti O2 hybrid photoanodes were prepared by the doctor-blade method using the slurry of Ti O2 nanocrystallite which was blended with Li4Ti5O12 powders. The effects of the mass ratio of Li4Ti5O12 to Ti O2, the crystallinity and the porous structure of Li4Ti5O12 powders on the performance of DSSC were examined. Results show that with the annealing temperature increasing, the crystallinity of the Li4Ti5O12 powders is enhanced, the crystallite size increased obviously, and the specific surface area decreased dramatically. The Li4Ti5O12-Ti O2 hybrid photoanodes exhibit higher dye-loading capacity and lower resistance at Ti O2/dye/electrolyte interface than does the pure Ti O2 counterpart, accompanied by higher Jsc（Jsc=13.91 m A/cm^2） and Voc（Voc =0.8 V） values than by the Ti O2 photoanode. The highest conversion efficiency（7.011%） is achieved by 1wt% Li4Ti5O12 hybrid cell, which is 30% higher than by the Ti O2 nanocrystallite counterpart（5.384%）.