Meng Weijia, Han Jun, Dang Zhenzhen, Li Diansen, Jiang Lei
Key Laboratory of Bio-Inspired Smart Interfacial Science and Technology, Ministry of Education, School of Chemistry, Beihang University, Beijing 100191, China.
Beijing Advanced Innovation Center for Biomedical Engineering, Beihang University, Beijing 100191, China.
ACS Appl Mater Interfaces. 2021 Sep 22;13(37):44214-44223. doi: 10.1021/acsami.1c10506. Epub 2021 Sep 14.
The sluggish sodium-ion diffusion kinetics and low electronic conductivity have severely restricted the development of the TiO anode for sodium-ion batteries. Defect engineering, such as single-heteroatom doping and oxygen vacancies, has proven to be effective methods to improve the conductivity of TiO, but a comprehensive understanding of the synergistic effect of dual-heteroatom doping and oxygen vacancies on the sodium storage performance of TiO is still lacking. Herein, we design a synergistic strategy of dual doping via the in situ doping and hydrogenation treatment to improve conductivity and cycling stability of TiO. Experiments and theoretical calculations together revealed that N and C doping reduces the band gap of TiO, while the presence of oxygen vacancies efficiently accelerates the diffusion of sodium ions. Thus N, C, and oxygen vacancies with high concentration co-doped TiO, resulting in extraordinary high-rate performance, significant stable cycling, and long-term cyclability of up to 10,000 cycles. The synthesis strategy of dual doping proposed here emphasizes the importance of defect engineering in improving material conductivity and electrode cycling stability for possible practical applications in the near future.
钠离子扩散动力学迟缓以及电子传导率低严重制约了钠离子电池TiO负极的发展。缺陷工程，如单杂原子掺杂和氧空位，已被证明是提高TiO导电性的有效方法，但对于双杂原子掺杂和氧空位对TiO储钠性能的协同效应仍缺乏全面了解。在此，我们通过原位掺杂和氢化处理设计了一种双掺杂协同策略，以提高TiO的导电性和循环稳定性。实验和理论计算共同表明，N和C掺杂降低了TiO的带隙，而氧空位的存在有效地加速了钠离子的扩散。因此，高浓度的N、C和氧空位共掺杂TiO，实现了卓越的高倍率性能、显著的稳定循环以及高达10000次循环的长期循环稳定性。这里提出的双掺杂合成策略强调了缺陷工程在提高材料导电性和电极循环稳定性方面的重要性，有望在不久的将来实现实际应用。
