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1.
Carbon-coated Li3V2(PO4)3 cathode materials for lithium-ion batteries were prepared by a carbon-thermal reduction (CTR) method using sucrose as carbon source. The Li3V2(PO4)3/C composite cathode materials were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), and electrochemical measurement. The results show that the Li3V2(PO4)3 samples synthesized using sucrose as carbon source have the same monoclinic structure as the Li3V2(PO4)3 sample synthesized using acetylene black as carbon source. SEM image exhibits that the particle size is about 1 μm together with homogenous distribution. Electrochemical test shows that the initial discharge capacity of Li3V2(PO4)3 powders is 122 mAh·g−1 at the rate of 0.2C, and the capacity retains 111 mAh−g−1 after 50 cycles. 相似文献
2.
Wen Wu Ying Wang Xianyou Wang Quanqi Chen Xin Wang Shunyi Yang Xiuming Liu Jia Guo Zhenhua Yang 《Journal of Alloys and Compounds》2009,486(1-2):93-96
Orthorhombic structure FeF3 was synthesized by a liquid-phase method using FeCl3, NaOH and HF solution as starting materials, and the FeF3/V2O5 composites were prepared by milling the mixture of as-prepared FeF3 and the conductive V2O5 powder. The properties of FeF3/V2O5 composites were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), galvanostatic charge/discharge and cyclic voltammetry measurements. Results showed that the FeF3/V2O5 composites can be used as cathode material for lithium-ion battery. Electrochemical measurements in a voltage range of 2.0–4.5 V reveal that the addition of conductive V2O5 improves significantly the electrochemical performance of FeF3, and the FeF3/V2O5 composite prepared by milling for 3 h exhibits high discharge capacity and good cycle performance, and its discharge capacity maintains about 209 mAh g−1 at 0.1 C (23.7 mA g−1) after 30 cycles. 相似文献
3.
Y.Q. QiaoJ.P. Tu Y.J. MaiL.J. Cheng X.L. WangC.D. Gu 《Journal of Alloys and Compounds》2011,509(25):7181-7185
The multi-walled carbon nanotubes (MWCNTs) modified Li3V2(PO4)3/C composite is synthesized by polyvinyl alcohol (PVA) based carbon-thermal reduction method using MWCNTs as a highly conductive agent. PVA mainly supplies a reductive atmosphere to reduce V5+ and provides a network of carbon to inhibit the aggregation of Li3V2(PO4)3 particles. The amorphous carbon coating and MWCNTs co-modified composite shows excellent high-rate lithium intercalation/deintercalation property and cycling performance between 3.0 and 4.3 V. The discharge capacities of 131.7 and 122.9 mAh g−1 are obtained at rates of 1 C and 10 C, respectively, for the Li3V2(PO4)3/(C + MWCNTs). These improvements are attributed to the valid conducting networks of C + MWCNTs and the reduced Li3V2(PO4)3 particle size by the network carbon from the pyrolysis of PVA. 相似文献
4.
分别采用固相-水热法和球磨法制备磷酸亚铁锂-磷酸钒锂复合正极材料(LiFePO4-Li3V2(PO4)3)。电化学性能测试表明,LiFePO4-Li3V2(PO4)3复合正极材料的电化学性能远远高于 LiFePO4和 Li3V2(PO4)3单独作为正极材料的性能,并且以固相-水热法制备的复合材料性能优于以球磨法制得的复合材料。研究发现 LiFePO4-Li3V2(PO4)3复合材料有 4 个氧化还原峰,相当于 LiFePO4 和 Li3V2(PO4)3 氧化还原峰的叠加。采用固相-水热法制备的LiFePO4-Li3V2(PO4)3 复合材料形貌较为规则,且有新相物质产生,这是导致其电化学性能较好的原因。 相似文献
5.
由于LiFePO_4和Li_3V_2(PO_4)_3材料的特征相近,制备方法类似,提供了一种从废旧LiFePO_4和Li_3V_2(PO_4)_3混合电池中回收Li、Fe和V,再制备xLiFePO_4-yLi_3V_2(PO_4)_3的方法。在空气气氛中600℃热处理1h后,去除粘结剂PVDF使活性物质与集流体分离。调节Li、Fe、V和P摩尔比,球磨、锻烧,配制不同比例的xLiFePO_4-yLi_3V_2(PO_4)_3(x:y=5:1,7:1,9:1)复合电极材料。表征了其形貌、结构和电化学性能,结果表明,回收制备的复合材料将同时具备LiFePO_4和Li_3V_2(PO_4)_3两种材料的电化学性能,能显著改善LiFePO_4的倍率性能。 相似文献
6.
A sphere-like carbon-coated Li3V2(PO4)3 composite was synthesized by carbothermal reduction method with two sessions of ball milling followed by spray-drying with the dispersant of polyethylene glycol added. The structure, particle size, and surface morphology of the cathode material were investigated via X-ray diffraction, scanning electron microscopy, and high-resolution transmission electron microscopy. Results indicate that the Li3V2(PO4)3/C composite has a sphere-like morphology composed of a large number of carbon-coated ultrafine particles linked together with a monoclinic structure. In the voltage range of 3.0-4.3 V, it exhibits the discharge capacities of 130 mAh g−1 and 100 mAh g−1 at 0.2 C and 20 C rates, respectively. This behavior indicates that the obtained Li3V2(PO4)3/C material has excellent rate capability. 相似文献
7.
Porous Li4Ti5O12 anode material synthesized by one-step solid state method for electrochemical properties enhancement 总被引:2,自引:0,他引:2
Chih-Yuan LinJenq-Gong Duh 《Journal of Alloys and Compounds》2011,509(8):3682-3685
A porous Li4Ti5O12 anode material was successfully synthesized from mixture of LiCl and TiCl4 with 70 wt% oxalic acid by a modified one-step solid state method. The anode material Li4Ti5O12 exhibited a cubic spinel structure and only one voltage plateau occurred around 1.5 V. The initial capacity of porous Li4Ti5O12 was 167 and 133 mAh g−1 at 0.5 and 1C charge/discharge rate, respectively, and the capacity retention maintained above 98% after 200 cycles. The porous Li4Ti5O12 structure showed promising rate performance with a capacity of 70 mAh g−1 at charge/discharge 10C rate after 200 cycles. It was demonstrated that the porous structure could withstand 50C charge/discharge rate and exhibited excellent cycling stability. 相似文献
8.
Sichun Zhang Haiping Xia Jinhao Wang Yuepin Zhang 《Journal of Alloys and Compounds》2008,463(1-2):446-452
The near-stoichiometric LiNbO3 (SLN) single crystals doped Mn2+, Co2+ and Ni2+ in 0.5 mol% concentration in the raw compositions were grown by the Bridgman method under the conditions of taking K2O as flux, a high temperature gradient (90–100 °C/cm) for solid–liquid interface. The XRD, absorption spectra, excitation spectra and emission spectra have been carried out. From the absorption edges of Mn2+, Co2+ and Ni2+-doped SLN crystals, the molar ratio of [Li+]/[Nb5+] are estimated to be about 0.977. The absorption spectra of Mn2+:SLN have shown a broad absorption band centered at 571 nm (6A1g(6S) → 4T1g(4G)), three absorption peaks at 520, 549 and 612 nm (overlapping of the 4T1(F)–4A2(F), 4T1(F)–4T1(P)), and a wide absorption band at 1400 nm (4T1(F) → 4T2(F)) of Co2+:SLN, Ni2+:SLN, and five absorption peaks at 381 nm (3A2g(F) → 3T1g(P)), 733 nm (3A2g(F) → 3T1g(F)), 1280 nm (3A2g(F) → 3T2g(F)), 430 nm (3A2g(F) → 1T2g(D)), and 840 nm (3A2g(F) → 1E(D)) of Ni2+:SLN were observed. A red emission at 612 nm (4T1g(4G) → 6A1g(6S)) for Mn2+:SLN, a red emission at 775 nm (4T1(P) → 4T1(F)) for Co2+:SLN, and a green emission at 577 nm (1T2g(D) → 3A2g(F)) and a red emission at 820 nm (1T2g(D) → 3T2g(F)) for Ni2+:SLN were observed under excited by 416, 520 and 550 nm lights, respectively. The concentration distribution of Mn2+, Co2+and Ni2+ ion in SLN crystals was investigated primarily from the absorption and emission spectra for various parts. The effective distribution coefficient for Mn2+ was less than 1. While, for Co2+ and Ni2+ were more than 1. 相似文献
9.
New pyrophosphate Sn0.9Sc0.1(P2O7)1−δ was prepared by an aqueous solution method. The structure and conductivity of Sn0.9Sc0.1(P2O7)1−δ have been investigated. XRD analysis indicates that Sn0.9Sc0.1(P2O7)1−δ exhibits a 3 × 3 × 3 super structure. It was found that Sn0.9Sc0.1(P2O7)1−δ prepared by an aqueous method is not conductive. The total conductivity of Sn0.9Sc0.1(P2O7)1−δ in open air is 2.35 × 10−6 and 2.82 × 10−9 S/cm at 900 and 400 °C respectively. In wet air, the total conductivity is about two orders of magnitude higher (8.1 × 10−7 S/cm at 400 °C) than in open air indicating some proton conduction. SnP2O7 and Sn0.92In0.08(P2O7)1−δ prepared by an acidic method were reported fairly conductive but prepared by similar solution methods are not conductive. Therefore, the conductivity of SnP2O7-based materials might be related to the synthetic history. The possible conduction mechanism of SnP2O7-based materials has been discussed in detail. 相似文献
10.
Yu-Chang Si Li-Fang Jiao Hua-Tang Yuan Hai-Xia Li Yong-Mei Wang 《Journal of Alloys and Compounds》2009,486(1-2):400-405
LiV3O8 powders were prepared by combustion synthesis, using metallic nitrates as the oxidant and metal sources and urea as fuel. The effect of (Li + V)/CO(NH2)2 ratio and heat-treatment temperature on the structure and electrochemical properties were discussed. The electrochemical behavior of the product showed that sample B1 synthesized at 300 °C with 1:0.5 ratio of (Li + V)/CO(NH2)2 showed the highest initial discharge capacity of 317.3 mAh g−1 and the best cycle ability with 238.9 mAh g−1 after 30 cycles. 相似文献
11.
X.J. Chen G.S. Cao X.B. Zhao J.P. Tu T.J. Zhu 《Journal of Alloys and Compounds》2008,463(1-2):385-389
LiFe1−xVxPO4/C cathode materials (x = 0, 0.1, 02, 0.3, 0.4) were synthesized by solid-state reaction using polypropylene as the reducing agent and carbon precursor. XRD results show that Li9Fe3P8O29 and Li3V2(PO4)3 occur when vanadium was added. TEM images show that most of LiFe1−xVxPO4/C particles take on a spherical or quadrate shape with a size less than 200 nm. Electrochemical tests indicate that LiFe0.9V0.1PO4/C and LiFe0.8V0.2PO4/C have a flat discharge plateau at about 3.45 V versus Li+/Li and an initial discharge capacity higher than 150 mAh/g at 0.1 C. LiFe0.8V0.2PO4/C also performed relatively good cycle stability which is attributed to their high electronic conductivity as proved by the electrochemical impedance spectroscopy (EIS). Cyclic voltammogram (CV) curves demonstrate that as increase of content of vanadium, LiFe1−xVxPO4/C presents several couples of redox peaks. 相似文献
12.
SiC powder prepared by the Na flux method at 1023 K for 24 h and Ba were used as starting materials for synthesis of tribarium tetrasilicide acetylenide, Ba3Si4C2. Single crystals of the compound were obtained by heating the starting materials with Na at 1123 K for 1 h and by cooling to 573 K at a cooling rate of −5.5 K/h. The single crystal X-ray diffraction peaks were indexed with tetragonal cell dimensions of a = 8.7693(4) and c = 12.3885(6) Å, space group I4/mcm (No.140). Ba3Si4C2 has the Ba3Ge4C2 type structure which can be described as a cluster-replacement derivative of perovskite (CaTiO3), and contains isolated anion groups of slightly compressed [Si4]4− tetrahedra and [C2]2− dumbbells. The electrical conductivity measured for a not well-sintered polycrystalline sample was 2.6 × 10−2–7 × 10−3 S cm−1 in the temperature range of 370–600 K and slightly increased with increasing temperature. The Seebeck coefficient showed negative values of around −200 to −300 μV K−1. 相似文献
13.
Zipeng YanShu Cai Lijuan MiaoXing Zhou Yongming Zhao 《Journal of Alloys and Compounds》2012,511(1):101-106
Li2FeSiO4/C composites with in situ carbon coating were synthesized via sol-gel method based on acid-catalyzed hydrolysis/condensation of tetraethoxysilane (TEOS) with sucrose and l-ascorbic acid as carbon additives, respectively. As-obtained Li2FeSiO4/C composites prepared with l-ascorbic acid as a carbon additive are composed of nanoparticulate Li2FeSiO4 in an intimate contact with a continuous thin layer of residual carbon and exhibit large specific surface area up to 395.7 m2 g−1. The results indicate that structure of the residual carbon is graphene-rich with obviously lower disordered/graphene (D/G) ratio. These as-obtained Li2FeSiO4/C composites exhibit first discharge capacity of 135.3 mAh g−1 at C/16 and perform cycling stability, which are superior to those of Li2FeSiO4/C composites synthesized with sucrose as a carbon additive. 相似文献
14.
L.N. Ji J.B. Li J. Luo J.K. Liang Y.H. Liu J.Y. Zhang G.H. Rao 《Journal of Alloys and Compounds》2009,470(1-2):336-339
The subsolidus phase relations of the ternary system ZnO–K2O–P2O5 were investigated by means of X-ray diffraction (XRD). There are 7 binary compounds, 6 ternary compounds and 20 three-phase regions in this system. The phase diagram of the pseudo-binary system KZn4(PO4)3–ZnO was also investigated by means of XRD and differential thermal analysis (DTA) methods. KZn4(PO4)3–ZnO is a eutectic system with eutectic temperature about 952 °C and eutectic point at about 2 mol% ZnO. Only narrow composition range in the KZn4(PO4)3–ZnO system is suitable for the growth of ZnO crystals. 相似文献
15.
Li3V2(PO4)3 samples were synthesized by sol-gel route and high temperature solid-state reaction. The influence of Li3V2(PO4)3 as cathode materials for lithium-ion batteries on electrochemical performances was investigated. The structure of Li3V2(PO4)3 as cathode materials for lithium-ion batteries and morphology of Li3V2(PO4)3 were characterized by X-ray diffractometry (XRD) and scanning electron microscopy (SEM). Electrochemical performances were characterized by charge/discharge and AC impedance measurements. Li3V2(PO4)3 with smaller grain size shows better performances in terms of the discharge capacity and cycle stability. The improved electrochemical properties of Li3V2(PO4)3 are attributed to the refined grains and enhanced electrical conductivity. AC impedance measurements also show that the Li3V2(PO4)3 synthesized by sol-gel route exhibits significantly decreased charge-transfer resistance and shortened migration distance of lithium ions. 相似文献
16.
L.N. Ji J.B. Li Y.Q. Chen J. Luo J.K. Liang G.H. Rao 《Journal of Alloys and Compounds》2009,486(1-2):352-356
As a systematic search for suitable flux to grow zinc oxide single crystals, the subsolidus phase relations of the ternary system ZnO–Li2O–P2O5 were investigated by means of X-ray diffraction (XRD). There are 6 binary compounds, 5 ternary compounds and 17 three-phase regions in this system. A new compound, Li6Zn(P2O7)2, is found in this system based on XRD experiments. The phase diagrams of the pseudo-binary systems Li3PO4–ZnO and LiZnPO4–ZnO are investigated. It shows that the compounds, Li3PO4 and LiZnPO4, are not suitable as flux for the growth of ZnO single crystals below 1250 °C. 相似文献
17.
Junqing Pan Yanzhi Sun Zihao Wang Pingyu Wan Maohong Fan 《Journal of Alloys and Compounds》2009,470(1-2):75-79
In this paper we report a novel Mn3O4 electrode doped with nano-NaBiO3. It is demonstrated that doping with nano-NaBiO3 alters the electrochemical inertia of Mn3O4, converting it into a rechargeable secondary alkaline cathode material that exhibits highly efficient charge/discharge properties. While a pure Mn3O4 electrode can barely maintain a single charge and discharge cycle, the cycling capacity of the Mn3O4 electrode doped with nano-NaBiO3 can reach and become stable at 372 mAh g−1 under 60 mA g−1. The doped cathode can also maintain a cycling capacity of 261 mAh g−1 while holding a 95.3% reversible capacity after 60 cycles at a high rate of 500 mA g−1. Moreover, the experimental results indicate that charging time for an alkaline battery using doped Mn3O4 cathode could possibly shorten to as little as 30 min. 相似文献
18.
Yangping Hong Dagui Chen Zhibin Zhan Xianzhi Chen Peiwen Lv Fengbo Yan Feng Huang Jingkui Liang 《Journal of Alloys and Compounds》2009,482(1-2):49-52
The subsolidus phase relations of the ternary system ZnO–P2O5–MoO3 were investigated by means of X-ray diffraction (XRD). Seven binary compounds and eight 3-phase regions were determined, and no ternary compound was found in this system. The phase diagram of pseudo-binary system Zn3(PO4)2–Zn3Mo2O9 was also constructed through XRD and differential thermal analysis (DTA) methods, and the result reveals this system is eutectic system. The eutectic temperature is 904 °C and the corresponding component is 30% Zn3Mo2O9 and 70% Zn3(PO4)2. 相似文献
19.
Fe3O4 micro-spheres with nanoparticles close-packed architectures were synthesized via a simple chemical method using (NH4)2Fe(SO4)2·6H2O, hexamethylenetetramine, and NaF as reaction materials. This chemical synthesis took place in a vitreous jar under low temperature (90 °C) and atmospheric pressure. The morphology and structure of the as-synthesized products were characterized by field emission scanning electron microscopy (FE-SEM), X-ray diffraction (XRD), and Raman spectrum. Electrochemical properties of the as-synthesized Fe3O4 micro-spheres as anode electrode of lithium ion batteries were studied by conventional charge/discharge tests, which exhibit steady charge/discharge platforms at different current densities. The as-prepared Fe3O4 electrode shows high initial discharge capacity of 1166 and 1082 mAh g−1 at current density of 0.05 and 0.1 mA cm−2, respectively. 相似文献
20.
Hongfa XiangBingbing Tian Peichao LianZhong Li Haihui Wang 《Journal of Alloys and Compounds》2011,509(26):7205-7209
Li4Ti5O12/graphene composite was prepared by a facile sol-gel method. The lattice structure and morphology of the composite were investigated by X-ray diffraction (XRD) and scanning electronic microscopy (SEM). The electrochemical performances of the electrodes have been investigated compared with the pristine Li4Ti5O12 synthesized by a similar route. The Li4Ti5O12/graphene composite presents a higher capacity and better cycling performance than Li4Ti5O12 at the cutoff of 2.5-1.0 V, especially at high current rate. The excellent electrochemical performance of Li4Ti5O12/graphene electrode could be attributed to the improvement of electronic conductivity from the graphene sheets. When discharged to 0 V, the Li4Ti5O12/graphene composite exhibited a quite high capacity over 274 mAh g−1 below 1.0 V, which was quite beneficial for not only the high energy density but also the safety characteristic of lithium-ion batteries. 相似文献