Disordered spinel LiNi_0.5Mn_1.5O₄ cathode with improved rate performance for lithium-ion batteries

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• 作者：Nur Diyana Rosedhi^a ; Nurul Hayati Idris^a ; ^{nurulhayati@umt.edu.my" class="auth_mail" title="E-mail the corresponding author} ; Md Mokhlesur Rahman^b ; M.F. Md Din^c ; Jianli Wang^d
• 关键词：LiNi0.5Mn1.5O4 ; lithium-ion batteries ; cathode materials ; glycine
• 刊名：Electrochimica Acta
• 出版年：2016
• 出版时间：10 July 2016
• 年：2016
• 卷：206
• 期：Complete
• 页码：374-380
• 全文大小：2547 K

文摘

The high voltage LiNi_0.5Mn_1.5O₄ cathode with a disordered spinel structure is synthesized by a glycine-assisted low-temperature reaction follows by a thermal treatment at 750 °C, 850 °C, and 950 °C for 12 h. Glycine is used as a chelating agent for the first time to build required environment for shaping the precursor of LiNi_0.5Mn_1.5O₄ materials. The microstructure and morphology of the LiNi_0.5Mn_1.5O₄ product are characterized by X-ray diffraction, X-ray photoelectron spectroscopy, scanning electron microscopy, Brunauer-Emmett-Teller, and transmission electron microscopy. The sample prepares at 750 °C reveals small particles with well-defined crystals as confirmed by electron microscopy. Electrochemical results demonstrate that LiNi_0.5Mn_1.5O₄ electrode anneal at 750 °C (compare to other two samples) delivers the highest reversible capacity of 110 mAh g⁻¹ at 0.2C after 100 cycles with good rate capability. The enhanced electrochemical performance could be attributed to the smaller particle sizes as well as well-defined crystals which provide a directional and shorter diffusion path length for Li⁺ transportation within the crystals.