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1.
Spinel Li4Ti5 − x
Zr
x
O12/C (x = 0, 0.05) were prepared by a solution method. The structure and morphology of the as-prepared samples were characterized
by X-ray diffraction, scanning electron microscopy, and transmission electron microscopy. The electrochemical performances
including charge–discharge (0–2.5 V and 1–2.5 V), cyclic voltammetry, and ac impedance were also investigated. The results
revealed that the Li4Ti4.95Zr0.05O12/C had a relatively smaller particle size and more regular morphology than that of Li4Ti5O12/C. Zr4+ doping enhanced the ability of lithium-ion diffusion in the electrode. It delivered a discharge capacity 289.03 mAh g−1 after 50 cycles for the Zr4+-doped Li4Ti5O12/C while it decreased to 264.03 mAh g−1 for the Li4Ti5O12/C at the 0.2C discharge to 0 V. Zr4+ doping did not change the electrochemical process, instead enhanced the electronic conductivity and ionic conductivity. The
reversible capacity and cycling performance were effectively improved especially when it was discharged to 0 V. 相似文献
2.
锂离子电池负极材料Li_(4-x)K_xTi_5O_(12)结构和电化学性能 总被引:1,自引:0,他引:1
采用固相反应的方法制备了尖晶石型Li4Ti5O12和K掺杂Li4-xKxTi5O12(x=0.02,0.04,0.06)。通过XRD、SEM、BET等对制备材料进行了分析。结果表明,K掺杂没有影响立方尖晶石型Li4Ti5O12的合成,同时也没有改变Li4Ti5O12的电化学反应过程。K掺杂Li4-xKxTi5O12具有比Li4Ti5O12小的颗粒粒径和比Li4Ti5O12大的比表面积、孔容积。适量的K掺杂能够明显改善Li4Ti5O12的电化学性能,尤其是倍率性能,但是过多的K掺杂却不利于材料电化学性能的提高。研究表明,Li3.96K0.04Ti5O12体现了相对较好的倍率性能和循环稳定性。0.5C下,首次放电比容量为161mAh·g-1,3.0和5.0C下,容量保持分别为138和121mAh·g-1。3.0C下,200次循环后容量保持为137mAh·g-1。 相似文献
3.
Bingbing Tian Hongfa Xiang Le Zhang Haihui Wang 《Journal of Solid State Electrochemistry》2012,16(1):205-211
Li4Ti4.95Nb0.05O12 is synthesized by a citric acid-assistant sol–gel method. X-ray diffraction (XRD) reveals that highly crystalline Li4Ti4.95Nb0.05O12 without any impurity is obtained. The electrochemical performances of the Li4Ti4.95Nb0.05O12 and the Li4Ti5O12 in the range from 0 to 2.5 V are investigated. The Li4Ti4.95Nb0.05O12 presents a higher specific capacity and better cycling stability than the Li4Ti5O12 due to the improved conductivity. The Li4Ti4.95Nb0.05O12 exhibits a capacity as high as 231.2 mAh g−1 after 100 cycles, which is much higher than the Li4Ti5O12 (111.1 mAh g−1). The effect of Nb-doping on electrochemical performance of Li4Ti5O12 discharged to 0 V has also been discussed. 相似文献
4.
Caixia Qiu Zhongzhi Yuan Ling Liu Neng Ye Jincheng Liu 《Journal of Solid State Electrochemistry》2013,17(3):841-847
A sol–gel method using Ti(OC4H9)4, LiCH3COO·2H2O, and La(NO3)3·6H2O as starting materials and ethyl acetoacetate as chelating agent to prepare pure and lanthanum (La)-doped Li4Ti5O12 is reported. The structure and morphology of the active materials characterized by powder X-ray diffraction and scanning electron microscopy analysis indicate that doping with a certain amount of La3+ does not affect the structure of Li4Ti5O12, but can restrain the agglomeration of the particles during heat treatment. The electrochemical properties measured by cyclic voltammetry, electrochemical impedance spectroscopy, and galvanostatic charge–discharge cycling tests show that La-doped Li4Ti5O12 presents a much improved electrochemical performance due to a decrease in charge transfer resistance. At current densities of 1 and 5 C, the La-doped Li4Ti5O12 exhibits excellent reversible capacities of 156.16 and 150.79 mAh?g?1, respectively. The excellent rate capability and good cycling performance make La-doped Li4Ti5O12 a promising anode material for lithium-ion batteries in energy storage systems. 相似文献
5.
Dr. Irantzu Sádaba Dr. Manuel Ojeda Prof. Rafael Mariscal Prof. Ryan Richards Prof. Manuel López Granados 《Chemphyschem》2012,13(14):3282-3292
A series of Mg‐Zr mixed oxides with different nominal Mg/ (Mg+Zr) atomic ratios, namely 0, 0.1, 0.2, 0.4, 0.85, and 1, is prepared by alcogel methodology and fundamental insights into the phases obtained and resulting active sites are studied. Characterization is performed by X‐ray diffraction, transmission electron microscopy, X‐ray photoelectron spectroscopy, N2 adsorption–desorption isotherms, and thermal and chemical analysis. Cubic MgxZr1?xO2?x solid solution, which results from the dissolution of Mg2+ cations within the cubic ZrO2 structure, is the main phase detected for the solids with theoretical Mg/ (Mg+Zr) atomic ratio ≤0.4. In contrast, the cubic periclase (c‐MgO) phase derived from hydroxynitrates or hydroxy precursors predominates in the solid with Mg/(Mg+Zr)=0.85. c‐MgO is also incipiently detected in samples with Mg/(Mg+Zr)=0.2 and 0.4, but in these solids the c‐MgO phase mostly arises from the segregation of Mg atoms out of the alcogel‐derived c‐MgxZr1?xO2?x phase during the calcination process, and therefore the species c‐MgO and c‐MgxZr1?xO2?x are in close contact. Regarding the intrinsic activity in furfural–acetone aldol condensation in the aqueous phase, these Mg? O? Zr sites located at the interface between c‐MgxZr1?xO2?x and segregated c‐MgO display a much larger intrinsic activity than the other noninterface sites that are present in these catalysts: Mg? O? Mg sites on c‐MgO and Mg? O? Zr sites on c‐MgxZr1?xO2?x. The very active Mg? O? Zr sites rapidly deactivate in the furfural–acetone condensation due to the leaching of active phases, deposition of heavy hydrocarbonaceous compounds, and hydration of the c‐MgO phase. Nonetheless, these Mg‐Zr materials with very high specific surface areas would be suitable solid catalysts for other relevant reactions catalyzed by strong basic sites in nonaqueous environments. 相似文献
6.
Li4Ti5O12 as the well-known “zero strain” anode material for lithium ion batteries (LIBs) suffers from low intrinsic ionic and electronic conductivity. The strategy of lattice doping has been widely taken to relieve the intrinsic issues. But the roles of the dopants are poorly understood. Herein, we propose to modulate the crystal structure and improve the electrochemical performance of Li4Ti5O12 by substituting Li and Ti with Ca and Sm, respectively. The roles of Ca and Sm on the crystal structure and electrochemical performances have been comprehensively investigated by means of X-ray diffraction (XRD), neutron diffraction (ND) and electrochemical analysis. The Rietveld refinement of ND data indicate that Ca and Sm prefer to take 8a site (tetrahedral site) and 16d site (octahedral site), respectively. Li3.98Ca0.02Ti4.98Sm0.02O12 has the longer Li1-O bond and shorter Ti-O bond length which reduces Li+ migration barrier as well as enhances the structure stability. Ca-Sm co-doping also alleviates the electrode polarization and enhances the reversibility of oxidation and reduction. In compared to bare Li4Ti5O12 and Li3.95Ca0.05Ti4.95Sm0.05O12, Li3.98Ca0.02Ti4.98Sm0.02O12 electrode shows the lower charge transfer resistance, higher Li+ diffusion coefficient, better rate capability and cycling performance. The proposed insights on the roles of dopants are also instructive to design high performance electrode materials by lattice doping. 相似文献
7.
The structural and electronic properties of Li4+xTi5O12 compounds (with 0≤x≤6)—to be used as anode materials for lithium‐ion batteries—are studied by means of first principles calculations. The results suggest that Li4Ti5O12 can be lithiated to the state Li8.5Ti5O12, which provides a theoretical capacity that is about 1.5 times higher than that of the compound lithiated to Li7Ti5O12. Further insertion of lithium species into the Li8.5Ti5O12 lattice results in a clear structural distortion. The small lattice expansion observed upon lithium insertion (about 0.4 % for the lithiated material Li8.5Ti5O12) and the retained [Li1Ti5]16dO12 framework indicate that the insertion/extraction process is reversible. Furthermore, the predicted intercalation potentials are 1.48 and 0.05 V (vs Li/Li+) for the Li4Ti5O12/Li7Ti5O12 and Li7Ti5O12/Li8.5Ti5O12 composition ranges, respectively. Electronic‐structure analysis shows that the lithiated states Li4+xTi5O12 are metallic, which is indicative of good electronic‐conduction properties. 相似文献
8.
Improving the Electrochemical Performance of the Li4Ti5O12 Electrode in a Rechargeable Magnesium Battery by Lithium–Magnesium Co‐Intercalation
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Na Wu Zhen‐Zhong Yang Hu‐Rong Yao Dr. Ya‐Xia Yin Prof. Lin Gu Prof. Yu‐Guo Guo 《Angewandte Chemie (International ed. in English)》2015,54(19):5757-5761
Rechargeable magnesium batteries have attracted recent research attention because of abundant raw materials and their relatively low‐price and high‐safety characteristics. However, the sluggish kinetics of the intercalated Mg2+ ions in the electrode materials originates from the high polarizing ability of the Mg2+ ion and hinders its electrochemical properties. Here we report a facile approach to improve the electrochemical energy storage capability of the Li4Ti5O12 electrode in a Mg battery system by the synergy between Mg2+ and Li+ ions. By tuning the hybrid electrolyte of Mg2+ and Li+ ions, both the reversible capacity and the kinetic properties of large Li4Ti5O12 nanoparticles attain remarkable improvement. 相似文献
9.
A series of Ti1-xZrxO2 materials were synthesized through a multistep sol-gel process. The structural characteristics were investigated using X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and Raman measurements. The experimental results showed that a solid solution could be obtained at low Zr/(Ti+Zr) molar ratios (x ≤0.319). Raman measurements exhibited that the presence of zirconium in the solid solutions greatly retarded the amorphous-anatase and anatase-rutile transitions. The diffuse reflectance UV-Vis spectra revealed that the bandgap of the solid solution was enlarged gradually with the increment of incorporated zirconium content. The Ti1-xZrxO2 solid solutions exhibited higher photocatalytic activity than pure TiO2 for the degradation of 4-chlorophenol aqueous solution. 相似文献
10.
The poor electronic conductivity restricts the wide applications of Li4Ti5O12 as anode materials in Li‐ion batteries. We report a facile approach to fabricate nitrogen‐doped carbon‐coated Li4Ti5O12 through carbonizing pyrrole and pyridine at different temperatures. Comparative experiments demonstrated that the carbon content plays a key role in governing the cycling performance and rate capability of Li4Ti5O12. The composites with higher carbon content exhibited superior cycling performance, and the composite prepared at 600 °C using pyridine as the carbon source gave the best cycling and rate performance. 相似文献
11.
Peony‐like spinel Li4Ti5O12 was synthesized via calcination of precursor at the temperature of 400°C, and the precursor was prepared through a hydrothermal process in which the reaction of hydrous titanium oxide with lithium hydroxide was conducted at 180°C. The as‐prepared product was investigated by SEM, TEM and XRD, respectively. As anode material for lithium ion battery, the Li4Ti5O12 obtained was also characterized by galvanostatic tests and cyclic voltammetry measurements. It is found that the peony‐like Li4Ti5O12 exhibited high rate capability of 119.7 mAh·g−1 at 10 C and good capacity retention of 113.8 mAh·g−1 after 100 cycles at 5 C, and these results indicate the peony‐like Li4Ti5O12 has promising applications for lithium ion batteries with high performance. 相似文献
12.
Huang Yudai Qi Yanling Jia Dianzeng Wang Xingchao Guo Zaiping Cho Won Il 《Journal of Solid State Electrochemistry》2012,16(5):2011-2016
Li4Ti5O12−x
Cl
x
(0 ≤ x ≤ 0.3) compounds were synthesized successfully via high temperature solid-state reaction. X-ray diffraction and scanning
electron microscopy were used to characterize their structure and morphology. Cyclic voltammetry, electrochemical impedance
spectroscopy, and charge/discharge cycling performance tests were used to characterize their electrochemical properties. The
results showed that the Li4Ti5O12−x
Cl
x
(0 ≤ x ≤ 0.3) compounds were well-crystallized pure spinel phase and that the grain sizes of the samples were about 3–8 μm. The
Li4Ti5O11.8Cl0.2 sample presented the best discharge capacity among all the samples and showed better reversibility and higher cyclic stability
compared with pristine Li4Ti5O12. When the discharge rate was 0.5 C, the Li4Ti5O11.8Cl0.2 sample presented the superior discharge capacity of 148.7 mAh g−1, while that of the pristine Li4Ti5O12 was 129.8 mAh g−1; when the discharge rate was 2 C, the Li4Ti5O11.8Cl0.2 sample presented the discharge capacity of 120.7 mAh g−1, while that of the pristine Li4Ti5O12 was only 89.8 mAh g−1. 相似文献
13.
Structural and Electrochemical Study of Vanadium‐Doped TiO2 Ramsdellite with Superior Lithium Storage Properties for Lithium‐Ion Batteries
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Dr. Juan Carlos Pérez‐Flores Dr. Markus Hoelzel Dr. Flaviano García‐Alvarado Dr. Alois Kuhn 《Chemphyschem》2016,17(7):1062-1069
Titanium‐oxide‐based materials are considered attractive and safe alternatives to carbonaceous anodes in Li‐ion batteries. In particular, the ramsdellite form TiO2(R) is known for its superior lithium‐storage ability as the bulk material when compared with other titanates. In this work, we prepared V‐doped lithium titanate ramsdellites with the formula Li0.5Ti1?xVxO2 (0≤x≤0.5) by a conventional solid‐state reaction. The lithium‐free Ti1?xVxO2 compounds, in which the ramsdellite framework remains virtually unaltered, are easily obtained by a simple aqueous oxidation/ion‐extraction process. Neutron powder diffraction is used to locate the Li channel site in Li0.5Ti1?xVxO2 compounds and to follow the lithium extraction by difference‐Fourier maps. Previously delithiated Ti1?xVxO2 ramsdellites are able to insert up to 0.8 Li+ per transition‐metal atom. The initial gravimetric capacities of 270 mAh g?1 with good cycle stability under constant current discharge conditions are among the highest reported for bulk TiO2‐related intercalation compounds for the threshold of one e? per formula unit. 相似文献
14.
Li Wang Qizhen Xiao Zhaohui Li Gangtie Lei Ping Zhang Lijuan Wu 《Journal of Solid State Electrochemistry》2012,16(10):3307-3313
Porous lithium titanate (Li4Ti5O12) fibers, composed of interconnected nanoparticles, are synthesized by thermally treating electrospun precursor fibers and utilized as an energy storage material for rechargeable lithium-ion batteries. The material is characterized by X-ray diffraction, scanning electron microscopy, high-resolution transmission electron microscopy, and thermal analysis. Scanning electron microscopy results show that the Li4Ti5O12 fibers calcined at 700?°C have an average diameter of 230?nm. Especially, the individual fiber is composed of nanoparticles with an average diameter of 47.5?nm. Electrochemical properties of the material are evaluated using cyclic voltammetry, galvanostatic cycling, and electrochemical impedance spectroscopy. The results show that as-prepared Li4Ti5O12 exhibits good cycling capacity and rate capability. At the charge–discharge rate of 0.2, 0.5, 1, 2, 10, 20, 40, and 60?C, its discharge capacities are 172.4, 168.2, 163.3, 155.9, 138.7, 123.4, 108.8, and 90.4?mAh?g?1, respectively. After 300 cycles at 20?C, it remained at 120.1?mAh?g?1. The obtained results thus strongly support that the electrospun Li4Ti5O12 fibers could be one of the most promising candidate anode materials for lithium-ion batteries in electric vehicles. 相似文献
15.
Li4Ti5O12/(Cu+C)复合材料的制备及电化学性能 总被引:1,自引:0,他引:1
以Li4Ti5O12,Cu(CH3COO)2·H2O和C6H12O6为前驱体,化学沉积与热分解结合合成锂离子电池负极材料Li4Ti5O12/(Cu+C)。采用X-射线衍射(XRD)、扫描电子显微镜(SEM)、恒流充放电、循环伏安和电化学阻抗方法表征样品的结构、形貌和电化学性能。结果表明,Li4Ti5O12表面包覆的Cu与C提高了Li4Ti5O12电极材料的导电率,其循环性能和倍率性能得到有效地改善。在0.5C、1C和3C倍率下,经过50次充放电循环,放电比容量分别为168.2、160、140.6 mAh·g-1,其容量保持率分别为88.7%、84.4%、71.2%。电化学阻抗测试表明,表面包覆的Cu与C使其电荷转移阻抗大幅度减少。 相似文献
16.
Changyao Wang Xiaoyue Wan Linlin Duan Peiyuan Zeng Liangliang Liu Dingyi Guo Yuan Xia Ahmed A. Elzatahry Yongyao Xia Wei Li Dongyuan Zhao 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2019,131(44):16010-16015
A molecular design strategy is used to construct ordered mesoporous Ti3+‐doped Li4Ti5O12 nanocrystal frameworks (OM‐Ti3+‐Li4Ti5O12) by the stoichiometric cationic coordination assembly process. Ti4+/Li+‐citrate chelate is designed as a new molecular precursor, in which the citrate can not only stoichiometrically coordinate Ti4+ with Li+ homogeneously at the atomic scale, but also interact strongly with the PEO segments in the Pluronic F127. These features make the co‐assembly and crystallization process more controllable, thus benefiting for the formation of the ordered mesostructures. The resultant OM‐Ti3+‐Li4Ti5O12 shows excellent rate (143 mAh g?1 at 30 C) and cycling performances (<0.005 % fading per cycle). This work could open a facile avenue to constructing stoichiometric ordered mesoporous oxides or minerals with highly crystalline frameworks. 相似文献
17.
The effect of anion distribution on the stability of β‐zirconium oxide nitride Zr7O8N4 (trigonal, ; a = 953.80(2) pm, c = 884.98(3) pm, Z=3) has been investigated quantum‐chemically. In agreement with experimental results for the structurally related β′‐type zirconium oxide nitride (Zr7O11N2) nitride anions occupy sites in the central polyhedron of a Bevan cluster (A7X12 unit) in the most stable configurations. Other relevant structural ordering parameters are minimization of N3?···N3? contacts and of the number of quasi‐linear N–Zr–N bonds. The calculated electronic structure of β‐Zr7O8N4 is in qualitative agreement with experimental observations. 相似文献
18.
Yunyan Zhao Shuping Pang Chuanjian Zhang Qinghua Zhang Lin Gu Xinhong Zhou Guicun Li Guanglei Cui 《Journal of Solid State Electrochemistry》2013,17(5):1479-1485
Nitridated mesoporous Li4Ti5O12 spheres were synthesized by a simple ammonia treatment of Li4Ti5O12 derived from mesoporous TiO2 particles and lithium acetate dihydrate via a solid state reaction in the presence of polyethylene glycol 20000. The carbonization of polyethylene glycol could effectively restrict the growth of primary particles, which was favorable for lithium ions diffusing into the nanosized TiO2 lattice during the solid state reaction to form a pure phase Li4Ti5O12. After a subsequent thermal nitridation treatment, a high conductive thin TiO x N y layer was in situ constructed on the surface of the primary nanoparticles. As a result, the nitridated mesoporous Li4Ti5O12 structure, possessing shorter lithium-ion diffusion path and better electrical conductivity, displays significantly improved rate capability. The discharge capacity reaches 138 mAh?g?1 at 10 C rate and 120 mAh?g?1 at 20 C rate in the voltage range of 1–3 V. 相似文献
19.
Dr. Jun Ma Dr. Yong‐Ning Zhou Dr. Yurui Gao Prof. Qingyu Kong Prof. Zhaoxiang Wang Prof. Xiao‐Qing Yang Prof. Liquan Chen 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(28):8723-8730
Lithium‐rich layer‐structured oxides xLi2MnO3? (1?x)LiMO2 (0<x<1, M=Mn, Ni, Co, etc.) are interesting and potential cathode materials for high energy‐density lithium ion batteries. However, the characteristic charge compensation contributed by O2? in Li2MnO3 leads to the evolution of oxygen during the initial Li+ ion extraction at high voltage and voltage fading in subsequent cycling, resulting in a safety hazard and poor cycling performance of the battery. Molybdenum substitution was performed in this work to provide another electron donor and to enhance the electrochemical activity of Li2MnO3‐based cathode materials. X‐ray diffraction and adsorption studies indicated that Mo5+ substitution expands the unit cell in the crystal lattice and weakens the Li?O and Mn?O bonds, as well as enhancing the activity of Li2MnO3 by lowering its delithiation potential and suppressing the release of oxygen. In addition, the chemical environment of O2? ions in molybdenum‐substituted Li2MnO3 is more reversible than in the unsubstituted sample during cycling. Therefore molybdenum substitution is expected to improve the performances of the Li2MnO3‐based lithium‐rich cathode materials. 相似文献
20.
A spinel Li4Ti5O12 nanoplatelet/reduced graphite oxide nano-hybrid was successfully synthesized by a two-step microwave-assisted solvothermal reaction and heat treatment. The Li4Ti5O12 in the hybrid could deliver a discharge capacity of 154 mAhg? 1 of Li4Ti5O12 at 1 C-rate, 128 mAhg-1 of Li4Ti5O12 at 50 C-rate and 101 mAhg-1 of Li4Ti5O12 at 100 C-rate. It demonstrated promising potential as an anode material in a Li-ion battery with excellent rate capability and good cycling. 相似文献