Synthesis and electrochemical performance of Ti
By Qiao-Ying Huang and Zhi Wu and Jing Su and Yun-Fei Long and Xiao-Yan Lv and Yan-Xuan Wen
Published in Ceramics International
2016
Abstract
LiMnPO4/C, LiMn0.85Fe0.15PO4/C, LiMn0.92Ti0.08PO4/C and Li(Mn0.85Fe0.15)0.92Ti0.08PO4/C are prepared by a solid-state reaction route and characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM) and electrochemical tests. All samples are single phase with similar morphologies, particle sizes and carbon contents. Ti4+ and Fe2+ co-doping at the Mn-site greatly enhances the performance of LiMnPO4/C due to the synergistic effect between Ti4+ and Fe2+, resulting in an improvement in the dynamic stability of the olivine structure, lithium ion diffusion and electrochemical kinetics. Compared with LiMn0.85Fe0.15PO4/C and LiMn0.92Ti0.08PO4/C, Li(Mn0.85Fe0.15)0.92Ti0.08PO4/C shows a much higher discharge capacity and a better rate capability. It delivers a capacity of 144.4 mA h g?1 with a capacity retention ratio of approximately 100% after 50 cycles at 1 C. These results prove that Fe2+ and aliovalent ion co-doping at the Mn site is an effective way to improve the electrochemical properties of lithium manganese phosphate.