Gan Qingmeng, He Hanna, Zhu Youhuan, Wang Zhenyu, Qin Ning, Gu Shuai, Li Zhiqiang, Luo Wen, Lu Zhouguang
Department of Materials Science and Engineering, Guangdong Provincial Key Laboratory of Energy Materials for Electric Power , Southern University of Science and Technology , Shenzhen 518055 , China.
College of Chemistry and Chemical Engineering , Central South University , Changsha 410083 , China.
ACS Nano. 2019 Aug 27;13(8):9247-9258. doi: 10.1021/acsnano.9b03766. Epub 2019 Jul 30.
Phosphorus doping is an effective strategy to simultaneously improve the electronic conductivity and regulate the ionic diffusion kinetics of TiO being considered as anode materials for sodium ion batteries. However, efficient phosphorus doping at high concentration in well-crystallized TiO nanoparticles is still a big challenge. Herein, we propose a defect-assisted phosphorus doping strategy to selectively engineer the surface structure of TiO nanoparticles. The reduced TiO shell layer that is rich in oxygen defects and Ti species precisely triggered a high concentration of phosphorus doping (∼7.8 at. %), and consequently a TiO@TiO-P core@shell architecture was produced. Comprehensive characterizations and first-principle calculations proved that the surface-functionalized TiO-P thin layer endowed the TiO@TiO-P with substantially enhanced electronic conductivity and accelerated Na ion transportation, resulting in great rate capability (167 mA h g at 10 000 mA g) and stable cycling (99% after 5000 cycles at 10 A g). Combining X-ray diffraction with electron spin resonance clearly demonstrated the high reversibility and robust mechanical behavior of TiO@TiO-P upon long-term cycling. This work provides an interesting and effective strategy for precise heteroatoms doping to improve the electrochemical performance of nanoparticles.
磷掺杂是一种有效策略，可同时提高电子导电性并调节TiO（被视为钠离子电池负极材料）的离子扩散动力学。然而，在结晶良好的TiO纳米颗粒中进行高浓度的有效磷掺杂仍是一个巨大挑战。在此，我们提出一种缺陷辅助磷掺杂策略，以选择性地设计TiO纳米颗粒的表面结构。富含氧缺陷和Ti物种的还原TiO壳层精确地引发了高浓度的磷掺杂（约7.8原子％），从而产生了TiO@TiO-P核壳结构。综合表征和第一性原理计算证明，表面功能化的TiO-P薄层赋予TiO@TiO-P显著增强的电子导电性并加速了Na离子传输，从而具有出色的倍率性能（在10000 mA g下为167 mA h g）和稳定的循环性能（在10 A g下5000次循环后为99％）。结合X射线衍射和电子自旋共振清楚地证明了TiO@TiO-P在长期循环时具有高可逆性和稳健的机械性能。这项工作为精确杂原子掺杂以改善纳米颗粒的电化学性能提供了一种有趣且有效的策略。
