非化学计量比调控高电压尖晶石正极材料电化学性能研究

doi:10.15541/jim20170579

摘要/Abstract

摘要：

用一种简单的方法制备了高性能的高电压尖晶石正极材料, 主要是调控正极材料中锂与过渡金属的摩尔比, 即通过Ni_0.25Mn_0.75(OH)₂与Li₂CO₃进行高温固相反应制备了非化学计量比的Li_1.05Ni_0.5Mn_1.5O₄和化学计量比的LiNi_0.5Mn_1.5O₄尖晶石型高电压正极材料。用扫描电子显微镜、X射线衍射、中子衍射、拉曼光谱、X射线光电子能谱以及循环伏安曲线对其形貌、晶体结构及元素价态和电化学性能进行了表征。研究发现, 非化学计量比的Li_1.05Ni_0.5Mn_1.5O₄中由于金属离子随机分布于16 d位置, 所以Ni/Mn阳离子无序化程度更高。非化学计量比的高电压正极材料具有更为优异的倍率性能, 并且在400次循环后比容量保持率高达91.2%。同时, 原位X射线衍射测试结果表明, 在充放电过程中非化学计量比的高电压正极材料发生连续单一的相转变, 可以提高晶体结构的稳定性。因此, 非计量比的尖晶石Li_1.05Ni_0.5Mn_1.5O₄正极材料在高能量密度的锂离子电池中具有更广阔的应用前景。

关键词: 高电压, 尖晶石, 正极材料, 非化学计量比, 循环稳定性

Abstract:

In this study, a simple method to prepare high-voltage spinel cathode materials though controlling stoichiometric ratio in their compositions was reported. Non-stoichiometric and stoichiometric high-voltage spinel LiNi_0.5Mn_1.5O₄ cathode materials were prepared by solid-state reaction between Li₂CO₃ and Ni_0.25Mn_0.75(OH)₂ prcursor. Their morphologies, structures and electrochemical performance were characterized by scanning electron microscopy, X-ray diffraction, neutron diffraction, Raman spectroscopy, X-ray photoelectron spectroscopy, as well as electrochemical curves. The second particles occupied the similar sizes ~8 μm, which were composed of nanoparticles. Compared to stoichiometric LiNi_0.5Mn_1.5O₄, Ni/Mn cations in non-stoichiometric LiNi_0.5Mn_1.5O₄ sample distributed randomly, resulting in structure disorder demonstrated by the analysis of X-ray diffraction, neutron diffration and Raman spectroscopy. Less Mn³⁺ content in stoichiometric LiNi_0.5Mn_1.5O₄ sample was detected though X-ray photoelectron spectroscopy. It is believed that more Mn³⁺ content and Ni/Mn cation disorder would benefit rate cpability and cycling performance. As a result, non-stoichiometric LiNi_0.5Mn_1.5O₄ sample delivers superior dicharge capacity at higher rates, even though it shows relatively minor discharge capacity at low rates. What’s more, higher capacity retention for the non-stoichiometric LiNi_0.5Mn_1.5O₄ sample was found, which was promoted to 91.2% at 1.0C rate after 400 cycles. At the same time, in situ X-ray diffraction measurements revealed that single-step phase transformation for non-stoichiometric LiNi_0.5Mn_1.5O₄ sample significantly enhanced structural stability during the electrochemical process. Spinel LiNi_0.5Mn_1.5O₄ with non-stoichiometric composition provides a promising solution for their potential application in high-energy-density lithium-ion batteries.

Key words: high voltage, spinel-structured, cathode materials, non-stoichiometric, cycling stability

中图分类号:

TQ174

赛喜雅勒图, 王雪莹, 顾庆文, 夏永高, 刘兆平, 何杰. 非化学计量比调控高电压尖晶石正极材料电化学性能研究[J]. 无机材料学报, 2018, 33(9): 993-1000.

LEE Sai-Xi, WANG Xue-Yin, GU Qing-Wen, XIA Yong-Gao, LIU Zhao-Ping, HE Jie. Tuning Electrochemical Performance through Non-stoichiometric Compositions in High-voltage Spinel Cathode Materials[J]. Journal of Inorganic Materials, 2018, 33(9): 993-1000.

图/表 10

图1 (a) Non-stoichiometric-LNMO和(b)Stoichiometric-LNMO样品的SEM照片

Fig. 1 SEM images of (a) Non-stoichiometric-LNMO and (b) Stoichiometric-LNMO

图2 (a) Non-stoichiometric-LNMO和(b)Stoichiometric-LNMO样品的XRD图谱

Fig. 2 XRD patterns of (a) Non-stoichiometric-LNMO and (b) Stoichiometric-LNMO with refinement results

图3 (a) Non-stoichiometric-LNMO和 (b) Stoichiometric- LNMO样品的中子衍射图谱

Fig. 3 Neutron diffraction patterns of (a) Non-stoichiometric- LNMO and (b) Stoichiometric-LNMO

图4 Non-stoichiometric-LNMO和Stoichiometric-LNMO样品的拉曼光谱

Fig. 4 Raman spectra of Non-stoichiometric-LNMO and Stoichiometric LNMO

图5 (a) Non-stoichiometric-LNMO和(b) Stoichiomeric- LNMO样品的Mn 2P电子X射线光电子能谱图(XPS)

Fig. 5 XPS images of Mn 2P of (a) Non-stoichiometric- LNMO and (b) Stoichiometric-LNMO

图6 (a) Non-stoichiometric-LNMO和Stoichiometric-LNMO样品在0.2C电流密度下的首次充放电曲线;(b)在1.0C电流密度下的两个样品的循环性能以及库伦效率

Fig. 6 (a) Initial charge-discharge curves at 0.2C rate, and (b) cycling performance as well as coulombic efficiency at 1.0C rate for Non-stoichiometric-LNMO and Stoichiometric-LNMO samples

表1 不同合成方法制备的高压尖晶石材料性能的比较

Table 1 Comparison with different methods to prepare high-voltage spinel cathode materials

Ref.	1^st discharge capacity?(mAh.g^-1)	Cycling performance??	Rate capabiity?(mAh.g^-1)
[15]	124 (0.1C)	90(250 cycles)	120 (0.2C charge, 5C discharge)
[19]	129 (0.1C)	83(300 cycles)	110 (1C charge, 2C discharge)
[20]	135 (0.1C)	88(80 cycles)	-
This work	132.8 (0.2C)	91.2(400 cycles)	122.4 (1C charge, 2C discharge)

图7 (a) Non-stoichiometric-LNMO和(b) Stoichiometric-LNMO样品的循环伏安曲线图

Fig. 7 CV curves of (a) Non-stoichiometric-LNMO and (b) Stoichiometric-LNMO at the scan rate of 0.2 mV/s.

图8 (a) Non-stoichiometric-LNMO, (b)Stoichiometric- LNMO样品在不同倍率下的充放电曲线图和(c)倍率容量保持率曲线图

Fig. 8 Charge-discharge curves of (a) Non-stoichiometric- LNMO, (b) Stoichiometric-LNMO at different rates, and (c) Capacity retention at different rates

图9 (a) Non-stoichiometric-LNMO和(b) Stoichiomeric- LNMO 的原位XRD图谱

Fig. 9 In situ XRD results during lithium-ion intercalation or deintercalation of (a) Non-stoichiometric-LNMO and (b) Stoichiometric-LNMO samples

参考文献 27

[1]	BRUCE P G, FREUNBER S A, HARDWICK L J,et al. Li-O2 and Li-S batteries with high energy storage. Nat. Mater., 2012, 11(10): 19-29.
[2]	KANG B, CEDER G.Battery materials for ultra-fast charging and discharging.Nature, 2009, 458(7235): 190-193.
[3]	MIZUSHIMA K, JONES P C P, WISEMAN J B, et al. LixCoO2(0<x<1): a new cathode material for batteries of high energy density. Mater. Res. Bull., 1980, 15(6): 783-789.
[4]	ARREBOLA J C, CABALLERO A, CRUZ M,et al. Crystallinity control of a nanostructured LiNi0.5Mn1.5O4 spinel via polymer- assisted synthesis: a method for improving its rate capability and performance in 5 V lithium batteries. Adv. Funct. Mater., 2006, 16(14): 1904-1912.
[5]	GOODENOUGH J B, PARK K S, The Li-ion rechargeable battery: a perspective.J. Am. Chem. Soc., 2013, 135(4): 1167-1176.
[6]	RUHUL A, ILIAS B.Part I: Electronic and ionic transport properties of the ordered and disordered LiNi0.5Mn1.5O4 spinel cathode.J. Power Sources, 2017, 348: 311-317.
[7]	LIU D, ZHU W, TROTTIER J,et al. Spinel materials for high-voltage cathodes in Li-ion batteries. RSC Adv., 2014, 4(1): 154-167.
[8]	YOON T, PARK S, MUN J,et al. Failure mechanisms of LiNi0.5Mn1.5O4 electrode at elevated temperature. J. Power Sources, 2012, 215: 312-316.
[9]	MANTHIRAM A, CHEMELEWSKI K, LEE E S.A perspective on the high-voltage LiMn1.5Ni0.5O4 spinel cathode for lithium-ion batteries.Energy Environ. Sci., 2014, 7(4): 1339-1350.
[10]	CABANA J, CABANS C M, OMENYA F O,et al. Composition- structure relationships in the Li-ion battery electrode material LiNi0.5Mn1.5O4. Chem. Mater., 2012, 24(15): 2952-2964.
[11]	SONG J, SHIN D W, LU Y,et al. Role of oxygen vacancies on the performance of Li[Ni0.5-xMn1.5+x]O4 (x=0, 0.05, and 0.08) spinel cathodes for lithium-ion batteries. Chem. Mater., 2012, 24(15): 3101-3109.
[12]	MA X H, KANG B, CEDER G.High rate micron-sized ordered LiNi0.5Mn1.5O4. J. Electrochem. Soc., 2010, 157(8): A925-A931.
[13]	ZHENG J M, XIAO J, YU X,et al. Enhanced Li+ ion transport in LiNi0.5Mn1.5O4 through control of site disorder. Phys. Chem. Chem. Phys., 2012, 14(39): 13515-13521.
[14]	WANG Y, CAO G.Developments in nanostructured cathode materials for high-performance lithium-ion batteries.Adv. Mater., 2008, 20(12): 2251-2269.
[15]	XIAO J, CHEN X, SUSHKO P V,et al. High-performance LiNi0.5Mn1.5O4 spinel controlled by Mn3+ concentration and site disorder. Adv. Mater., 2012, 24(16): 2109-2116.
[16]	ZHANG X, CHENG F, ZHANG K,et al. Facile polymer-assisted synthesis of LiNi0.5Mn1.5O4 with a hierarchical micro-nanostructure and high rate capability. RSC Adv., 2012, 2(13): 5669-5675.
[17]	ZHENG J, XIAO J, YU X,et al. Enhanced Li+ ion transport in LiNi0.5Mn1.5O4 through control of site disorder. Phys. Chem. Phys., 2012, 14(39): 13515-13521.
[18]	KIM H, MYUNG S T, YOON C S,et al. Comparative study of LiNi0.5Mn1.5O4-δ and LiNi0.5Mn1.5O4 cathodes having two crystallographic structures: Fd3m and P4332 cathodes. Chem. Mater., 2004, 16(5): 906-914.
[19]	JO M R, KIM Y L, KIM Y,et al. Lithium-ion transport through a tailored disordered phase on the LiNi0.5Mn1.5O4 surface for high-power cathode materials. ChemSusChem, 2014, 7: 2248-2254.
[20]	LEE J, DUPRE N, AVDEEV M,et al. Understanding the cation ordering transition in high-voltage spinel LiNi0.5Mn1.5O4 by doping Li instead of Ni. Sci. Rep., 2017, 7: 6728-6739.
[21]	CHANG Z R, CHEN Z J, WU F,et al. Preparation of Li(Ni1/3Co1/3Mn1/3)O2 by spherical Ni1/3Mn1/3Co1/3OOH at a low temperature. J. Power Sources, 2008, 185: 1408-1414.
[22]	IDEMOTO Y, NARAI H, KOURA N. Crystal structure and cathode performance dependence on oxygen content of LiMn1.5Ni0.5O4 as a cathode material for secondary lithium batteries. J. Power Sources, 2003, 119-121: 125-129.
[23]	BACON G E.Coherent neutron scattering amplitudes.Acta Crystallographica Section A, 1972, 28(4): 357-358.
[24]	ARIYOSHI K, IWAKOSHI Y, NAKAYAMA N,et al. Topotactic two-phase reactions of Li[Ni1/2Mn3/2] O4(P4332) in nonaqueous lithium cells. J. Electrochem. Soc., 2004, 151(2): A296-A303.
[25]	OH S H, CHUNG K Y, JEON S H,et al. Structural and electrochemical investigations on the LiNi0.5-xMn1.5-yMx+yO4(M=Cr, Al, Zr) compound for 5 V cathode material. J. Alloys. Compd., 2009, 469(1/2): 244-250.
[26]	TERADA Y, YASAKA K, NISHIKAWA F,et al. In situ XAFS analysis of Li(Mn, M)2O4(M=Cr, Co, Ni) 5 V cathode materials for lithium-ion secondary batteries. J. Solid State Chem., 2001, 156(2): 286-291.
[27]	AMMUNDSEN B, ROZIERE J, ISLAM M S A. Atomistic simulation studies of lithium and proton insertion in spinel lithium manganese oxide. J. Phys. Chem. B, 1997, 101(41): 8155-8163.