Zhang Yaqing, Xie Hongyan, Jin Huixin, Li Xiaohui, Zhang Qiang, Li Yezhu, Li KaiFeng, Luo Fenglan, Li Wenlei, Li Chenzhe
College of Material and Metallurgy, Guizhou University, Guiyang 550025, China.
Guizhou Province Key Laboratory of Metallurgical Engineering and Process Energy Saving, Guiyang 550025, China.
ACS Omega. 2021 Aug 10;6(33):21304-21315. doi: 10.1021/acsomega.1c01521. eCollection 2021 Aug 24.
In this study, LiMn Ti O cathode materials were synthesized by a simple one-step hydrothermal method, and the effects of Ti doping on the sample structure and electrochemical properties were examined. The results indicated that Ti doping did not affect the spinel structure of LiMnO, and no other hybrid phases were produced. Furthermore, appropriate doping with Ti improved the particle uniformity of the samples. The electrochemical performance results showed that LiMnTiO exhibited much better cycling performance than the undoped sample. The discharge capacity of LiMnTiO reached 136 mAh g at 25 °C at 0.2C, and the specific capacity reached 106.2 mAh g after 300 cycles, with a capacity retention rate of 78.09%. Additionally, the specific capacity of LiMnTiO was 102.3 mAh g after 100 cycles at 55 °C, with a capacity retention rate of 75.44%. The Ti-doped samples thus exhibited an impressive high-rate performance. The discharge capacity of LiMnO was only 31.3 mAh g at 10C, while the discharge-specific capacity of LiMnTiO reached 73.4 mAh g. Furthermore, to assess the higher Li diffusion coefficient and lower internal resistance of the Ti-doped samples, cyclic voltammetry and impedance spectra data were obtained. Our results showed that Ti doping enhanced the crystal structure of LiMnO and improved Li diffusion, resulting in significant improvements in the cycling and rate performance of Ti-doped samples.
在本研究中，采用简单的一步水热法合成了LiMnTiO阴极材料，并研究了Ti掺杂对样品结构和电化学性能的影响。结果表明，Ti掺杂不影响LiMnO的尖晶石结构，也未产生其他杂相。此外，适量的Ti掺杂改善了样品的颗粒均匀性。电化学性能结果表明，LiMnTiO的循环性能比未掺杂样品好得多。LiMnTiO在25℃、0.2C下的放电容量达到136 mAh/g，300次循环后比容量达到106.2 mAh/g，容量保持率为78.09%。此外，LiMnTiO在55℃下100次循环后的比容量为102.3 mAh/g，容量保持率为75.44%。因此，Ti掺杂样品表现出令人印象深刻的高倍率性能。LiMnO在10C时的放电容量仅为31.3 mAh/g，而LiMnTiO的放电比容量达到73.4 mAh/g。此外，为了评估Ti掺杂样品具有更高的Li扩散系数和更低的内阻，获得了循环伏安法和阻抗谱数据。我们的结果表明，Ti掺杂增强了LiMnO的晶体结构并改善了Li扩散，从而显著提高了Ti掺杂样品的循环和倍率性能。
