摘要
PX-phase PbTiO3 （PT） nanowires with open channels running along the length direction have been investigated as an anode material for lithium ion batteries. This material shows a stabilized reversible specific capacity of about 410 mAh·g^-1 up to 200 cycles with a charge/discharge voltage plateau of around 0.3-0.65 V. In addition, it exhibits superior high-rate performance, with 90% and 77% capacity retention observed at 1 and 2 A·g^-1, respectively. At a very high current rate of 10 A·g^-1, a specific capacity of over 170 mAh·g^-1 is retained up to 100 cycles, significantly outperforming the rate capability reported for Pb and Pb oxides. The results of X-ray photoelectron spectroscopy （XPS） and transmission electron microscopy （TEM） analyses along with the cyclic voltammogram results reveal that the PX-phase PT nanowires undergo irreversible structural amorphization and reduction reactions during the initial cycle, which allow them to transform into a composite structure composed of 2-5 nm Pb nanoparticles uniformly dispersed in the 1D amorphous Li2O·TiO2·LiTiO2 matrix. In this composite structure, the presence of abundant amounts of Ti^3＋ in both the charged and discharged states enhances the electrical conductance of the system, whereas the presence of ultrafine Pb nanoparticles imparts high reversible capacity. The structurally stable TiO2-based amorphous matrix can also considerably buffer the volume variation during the charge/discharge process, thereby facilitating extremely stable cycling performance. This compound combines the high specific capacity of Pb-based materials and the good rate capability of Ti^3＋-based wiring. Our results might furnish a possible route for achieving superior cycling and rate performance and contribute towards the search for next-generation anode materials.
PX-phase PbTiO3 （PT） nanowires with open channels running along the length direction have been investigated as an anode material for lithium ion batteries. This material shows a stabilized reversible specific capacity of about 410 mAh·g^-1 up to 200 cycles with a charge/discharge voltage plateau of around 0.3-0.65 V. In addition, it exhibits superior high-rate performance, with 90% and 77% capacity retention observed at 1 and 2 A·g^-1, respectively. At a very high current rate of 10 A·g^-1, a specific capacity of over 170 mAh·g^-1 is retained up to 100 cycles, significantly outperforming the rate capability reported for Pb and Pb oxides. The results of X-ray photoelectron spectroscopy （XPS） and transmission electron microscopy （TEM） analyses along with the cyclic voltammogram results reveal that the PX-phase PT nanowires undergo irreversible structural amorphization and reduction reactions during the initial cycle, which allow them to transform into a composite structure composed of 2-5 nm Pb nanoparticles uniformly dispersed in the 1D amorphous Li2O·TiO2·LiTiO2 matrix. In this composite structure, the presence of abundant amounts of Ti^3＋ in both the charged and discharged states enhances the electrical conductance of the system, whereas the presence of ultrafine Pb nanoparticles imparts high reversible capacity. The structurally stable TiO2-based amorphous matrix can also considerably buffer the volume variation during the charge/discharge process, thereby facilitating extremely stable cycling performance. This compound combines the high specific capacity of Pb-based materials and the good rate capability of Ti^3＋-based wiring. Our results might furnish a possible route for achieving superior cycling and rate performance and contribute towards the search for next-generation anode materials.
基金
This work is supported by National Natural Science Foundation of China （No. 51302143）, Shenzhen Special Fund for the Development of Emerging Industries （No. JCYJ20140417115840233）, and Shenzhen Peacock Plan （No. KQCX20140521161756228）.
