High rate capability of LiFePO₄ cathodes doped with a high amount of Ti

详细信息    查看全文

• 作者：Sungjin Kim ; Vinod Mathew ; Jungwon Kang ; Jihyeon Gim ; Jinju Song ; Jeonggeun Jo ; Jaekook Kim ; ^{jaekook@chonnam.ac.kr" class="auth_mail" title="E-mail the corresponding author}
• 关键词：Lithium-ion battery ; Cathode materials ; Doping ; Electrochemistry ; High rate capability
• 刊名：Ceramics International
• 出版年：2016
• 出版时间：1 May 2016
• 年：2016
• 卷：42
• 期：6
• 页码：7230-7236
• 全文大小：1288 K

文摘

A Li-ion battery cathode with target stoichiometry LiTi_0.08Fe_0.92PO₄ was prepared by doping a high amount of Ti⁴⁺ into the olivine structure using solid-state reaction at 700 °C. Synchrotron X-ray diffraction studies confirmed the presence of a major olivine phase and NASICON-type ion-conducting Li₃Fe₂(PO)₄ and Li₂TiFe(PO₄)₃ impurities. Further, the calculated lattice parameter values appear to confirm Ti-doping in LiFePO₄. Electron microscopy and particle distribution studies not only revealed a slightly increased average particle-size and particle fragmentation but also confirmed a fair distribution of Ti⁴⁺ ions in the prepared sample. The LiTi_0.08Fe_0.92PO₄ cathode delivered high specific capacities and good capacity retentions (≤2% capacity loss after 50 cycles) for lithium battery applications. Besides, the cathode delivered impressive rate capabilities as specific capacities of 160 and 110 mA h g⁻¹ at 0.2 and 11.4 C, respectively, were retained. Although the average particle-size was slightly higher, the presence of ion-conducting NASICON-type species appear to contribute to the enhanced electrical conductivity and hence to the cathode performance of LiTi_0.08Fe_0.92PO₄.