Zhang Bao, Zeng Tao, Liu Yi, Zhang Jia-Feng
School of Metallurgy and Environment, Central South University Changsha 410083 PR China
Tianjin Lishen Battery Joint-Stock Co., Ltd Tianjin 300384 PR China.
RSC Adv. 2018 Feb 1;8(10):5523-5531. doi: 10.1039/c7ra12743j. eCollection 2018 Jan 29.
NaV Ti (PO) ( = 0.00, 0.05, 0.10, and 0.15) was successfully synthesized by a conventional solid-state route. The XRD results show that Ti is incorporated in the lattice of NaV(PO) and the tetragonal structure has not been changed after doping. Among all the composites, the NaVTi(PO) composite delivers the highest discharge capacity of 114.87 mA h g at 0.1C and possesses a capacity retention of 96.23% after 20 cycles at 0.1C, demonstrating the better rate performance and cycle stability in the potential range of 2.0-3.8 V. Electrochemical impedance spectroscopy (EIS) results reveal that the NaVTi(PO) composite has a lower charge transfer resistance and a higher Na-ion diffusion coefficient compared to other composites. The results indicate that Ti-doping in NaV(PO) can effectively enhance the electrochemical performance of this tetragonal compound, especially at a high charge/discharge rate.
通过传统的固态路线成功合成了NaVTi(PO)（x = 0.00、0.05、0.10和0.15）。X射线衍射结果表明，Ti掺入了NaV(PO)的晶格中，掺杂后四方结构未发生变化。在所有复合材料中，NaVTi(PO)复合材料在0.1C时的放电容量最高，为114.87 mA h g，在0.1C下循环20次后的容量保持率为96.23%，表明在2.0 - 3.8 V的电位范围内具有更好的倍率性能和循环稳定性。电化学阻抗谱（EIS）结果表明，与其他复合材料相比，NaVTi(PO)复合材料具有更低的电荷转移电阻和更高的Na离子扩散系数。结果表明，在NaV(PO)中掺杂Ti可以有效提高这种四方化合物的电化学性能，尤其是在高充/放电速率下。
