IONICS
·
2017
·Vol. 24
·期 3
·671-679
·
IF 2.062
Yan Yinglin,Li Qiaole,Ren Bing,Yang Rong,Xu Yunhua,Zhong Lisheng,Wu Hong
Hierarchical lithium iron phosphate/carbon (LiFePO 4 /C) microspheres were fabricated successfully using a facile spray drying-assisted coprecipitation method. A relatively short calcination time and a relatively low calcination temperature were adopted to prepare the hierarchical LiFePO 4 /C microspheres. The hierarchical microspheres consisted of nanoparticles with a uniform coating of amorphous carbon. The thickness of the carbon layer was controlled by the addition of glucose. The hierarchical LiFePO 4 /C microspheres exhibited a high tap density and a large specific surface area. The electrochemical properties of the sample were investigated. The sample exhibited a better rate capability and a better cyclability than the coral-like LiFePO 4 /C cathode material, and these were ascribed to the highly uniform carbon coating and the self-assembled nanoparticles.
研究领域:
材料科学
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电化学
✓ 已验证
产品关联
DOI
高影响因子
PHYSICAL CHEMISTRY CHEMICAL PHYSICS
·
2020
·Vol. 22
·期 4
·1953-1962
·
IF 3.43
Wenyuan Duan,Mingshu Zhao,Yusuke Mizuta,Yanlin Li,Tong Xu,Fei Wang,Toshihiro Moriga,Xiaoping Song
Olivine LiFePO4 covered flocculent carbon layers wrapped with carbon nanotubes (CNTs) prepared by sol–gel method and calcination is used as the cathode material for aqueous rechargeable lithium-ion batteries (ARLBs). The phase structures and morphologies of the composite material are characterized by X-ray diffraction (XRD), selected area electron diffraction (SAED), and transmission electron microscopy (TEM). The mechanism and method through which CNTs and flocculent carbon improve the electrochemical performance are investigated in an aqueous lithium-ion battery by setting up a comparative experiment. The ARLB system is assembled using a LiFePO4/C/CNTs cathode and a zinc anode in 1 mol L−1 ZnSO4·7H2O and saturated LiNO3 aqueous solution (pH = 6), which can deliver a capacity of 158 mA h g−1 at a rate of 1C. Even at a rate of 50C, it still has a capacity of 110 mA h g−1 after 250 cycles with fantastic capacity retention (95.7%). The lithium-ion diffusion coefficient increases by an order of magnitude due to the addition of CNTs together with flocculent carbon. Four LEDs are successfully powered by the ARLBs for more than one minute to demonstrate the practical application. The excellent rate capabilities and thrilling discharge capacity at a high rate indicate that this cathode material possesses excellent electrochemical performance, and this ARLB system exhibits excellent potential as a power source for environmental applications.
研究领域:
材料科学
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电化学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
Materials
·
2023
·Vol. 16
·期 22
·7155
·
IF 3.4
Haozhi Duan,Dehai Meng,Shuxia Yuan
Solution combustion synthesis (SCS) is considered as an efficient and energy-saving method for preparing LiFePO4/C composite material with the nanostructure (Nano-LiFePO4/C). In this study, Nano-LiFePO4/C cathode material was prepared using SCS using a cost-effective combination of urea and sorbitol as mixed fuels. The effect of mixed fuels on combustion behavior and microstructure as well as on electrochemical performance was studied using XRD, BET, SEM, TEM, and electrochemical characterization methods. Multiple characterization results indicated that the maximum temperature (Tm) and particle size were influenced by the usage of urea and sorbitol. The sample derived under optimum conditions exhibits a mesoporous nanostructure with a large surface specific area and attractive electrochemical performance with a discharge capacity of 153.5 mAh/g at 0.1 C, which shows strong potential for commercial applications in the future.Keywords:LiFePO4;cathode materials;solution combustion synthesis;electrochemical performance;mixed fuels
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DOI
PubMed
高影响因子
NEW JOURNAL OF CHEMISTRY
·
2017
·Vol. 41
·期 21
·12969-12975
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IF 3.269
Yue Zhang,Yudai Huang,Yakun Tang,Hongyang Zhao,Yanjun Cai,Xingchao Wang,Yong Guo,Dianzeng Jia,Jun Zong
Bicontinuous hierarchical mesoporous LiFePO4/C (BHM-LFP/C) microbelts have been synthesized using a simple dual-solvent electrospinning method for the first time. The use of a dual-solvent is beneficial for the electrospinning synthesis, which increases the salt solubility, as well as decreases the surface tension to improve the spinnability. The sample exhibits a high reversible capacity (153 mA h g−1 at 0.5C), and achieves an excellent high rate cycling performance. The enhanced electrochemical performance can be attributed to the unique microbelts providing bicontinuous electron/ion pathways, and the thoroughly mesoporous structure facilitating electrolyte penetration, especially for hierarchical architectures, which have three-dimensional diffusion channels for Li+. This method can be extended to fabricate other electrospun multi-element oxide cathode materials for advanced lithium-ion batteries.
研究领域:
材料科学
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电化学
✓ 已验证
DOI
高影响因子
VACUUM
·
2024
·
IF 3.8
Zuhong Ji,Yunfei Sun,Xiaodong Guan,Yang Zhou,Junchao Qian,Feng Chen
In this work, the La substitution of iron and replacing the oxygen with fluorine are both adopted to expectantly enhance the rate performance and structure stability of LiFePO 4 during working. The characterizations of X-ray diffraction, scanning electron microscope , transmission electron microscope, charging-discharging tests, electrochemical impedance spectroscopy and safety tests are used to investigate the influences of La 3+ and F − doping on the LiFePO 4 . The results indicate the cathodes after La 3+ doping not only deliver the larger lattice parameters and unit cell volume to broaden the lithium ions migration pathway and accelerate the Li + diffusion speed, but also strengthen the whole bond energy of LiFePO 4 owing to the high bond energy of La–O. In addition, the F replacement of O could increase the length of Li–O bonds and decrease the length of P–O bonds, further be helpful to enhance the Li + diffusion between LiFePO 4 phase and FePO 4 phase due to the weakening of Li–O bonds. Finally, the La 3+ and F − co-doped cathode delivers the superior discharge capacity of 139.3 mAh g −1 at 5C high rate and 127.2 mAh g −1 at −20 °C, with the high discharging capacity of 160.1 mAh g −1 after 100 cycles at 45 °C.
研究领域:
材料科学
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电化学
✓ 已验证
产品关联
DOI
高影响因子
IONICS
·
2021
·Vol. 28
·期 1
·191-200
·
IF 2.817
Chen Zi-Liang,Gu Yi-Jing,Luo Gui-Yang,Huo Yong-Lin,Wu Fu-Zhong
Although researchers have previously examined whether graphene modified by sulfur can improve the electrochemical performance of LiFePO 4 /C composites, they have rarely examined whether it can do so during the synchronous synthesis of LiFePO 4 /C and sulfur-modified reduced graphene oxide (SG) via a one-step hydrothermal method. To answer this question, a series of olivine structure LiFePO 4 /C composites wrapped with SG were investigated. Subsequently, we found that SG can form a three-dimensional conductive network on the surface of the LiFePO 4 /C sample. In the process, XRD and HRTEM tests were undertaken as well. From the XRD test, the results show that SG does not affect the olivine structure of LiFePO 4 /C. In the HRTEM experiment, clear lattice fringes and a uniformly coated carbon layer on the sample surface were observed. Alongside these results, there were 4 others. First, the charge–discharge data showed that the electrochemical performance of the samples could be increased by SG modification. Second, sample S2 with a mass ratio of Na 2 S to rGO of 1:10 shows the best specific discharge capacity and stability. Third, the specific capacity of S2 is 163 mAhg −1 at 0.2 C, and the capacity retention is 108.23% even after 200 cycles at a magnification of 10 C. Fourth, according to EIS, the charge migrating resistance of S2 is 226.4 Ω, and the lithium-ion diffusion coefficient is 2.41 × 10 −14 cm 2 ·S −1 . The significance of these results is that they indicate that wrapping LiFePO 4 /C with SG significantly contributed to the improvement of its electrochemical performance.
研究领域:
材料科学
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电化学
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储能技术
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纳米材料
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锂离子电池
✓ 已验证
DOI
高影响因子
JOURNAL OF POWER SOURCES
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2024
·
IF 8.1
Wenhui Tu,Zewei Chen,Yuanpeng Cao,Jianguo Duan,Jingjing He,Runlin Li,Peng Dong,Xianshu Wang,Yingjie Zhang,Ding Wang
Olivine-structured LiMnPO 4 -based cathodes have generated enormous development prospects due to their high energy density , good structural stability , and low cost. However, their scale of application is limited by high electronic and ionic insulativity. In this study, we designed and synthesized a bi-functional interfacial modified composite, 0.9LiMnPO 4 @0.1LiFePO 4 /C ( [email protected] /C ), using mechanochemical activation-assisted hydrothermal technology. The innovative Li-storage structure consists of a high-energy density LiMnPO 4 (LMP) core, a uniformly coated LiFePO 4 (LFP) layer with improved ionic conductivity as the secondary outer shell, and an in-situ coated carbon film with high conductivity as the outermost functional skin. As anticipated, the [email protected] /C composite exhibits outstanding Li-storage properties, demonstrating discharge capacities as high as 157.1 mAh g −1 and 146.7 mAh g −1 at 0.1 C and 1 C rates, respectively. Moreover, it exhibits an ultrahigh capacity retention of 92.5 % after 500 charge and discharge cycles.
研究领域:
材料科学
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电化学
✓ 已验证
DOI
高影响因子
JOURNAL OF THE ELECTROCHEMICAL SOCIETY
·
2024
·Vol. 171
·期 2
·020547
·
IF 3.1
Weida Li,Haoyan Gu,Hao Yang,Quanchen Li,Xinran Li,Yaping Wang,Guangchuan Liang
High volumetric energy density LiFePO4/C cathode materials were synthesized by wet ball milling, spray drying, and carbothermal reduction method using glucose and polyethylene glycol (PEG) as composite carbon sources and dodecyl polyglucoside (C12APG) as a milling aid. With the introduction of C12APG during the ball milling process, the prepared cathode materials have uniform particle size (100–200 nm in diameter) and regular primary particle morphology. In addition, PEG substitutes part of glucose as a carbon source, resulting in low carbon content and high graphitization of residual carbon after high-temperature calcination. The prepared LiFePO4/C cathode materials have a high powder compaction density (2.68 g cm−3) and excellent electrochemical performance (discharged capacities of 161.2 and 141.7 mAh g−1 at 0.2 C and 5 C, and cycle retention of 98.6% for 100 cycles at 1 C/1 C). This LiFePO4/C composite was assembled into 14500-type cylindrical batteries with a compaction density of 2.62 g cm−3 for the positive electrode. The volumetric energy densities of the positive electrode were 1135.18 Wh L−1 and 918.16 Wh L−1 at 0.2 C and 5 C, respectively.
研究领域:
材料科学
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电化学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF POWER SOURCES
·
2014
·
IF 5.211
Rongrong Chen,Yixiong Wu,Xiang Yang Kong
A microwave-assisted hydrothermal approach combined with carbothermal reduction has been developed to synthesize monodisperse porous LiFePO 4 /C microspheres , which possess the diameter range of 1.0–1.5 μm, high tap density of ∼1.3 g cm −3 , and mesoporous characteristic with Brunauer–Emmett–Teller (BET) surface area of 30.6 m 2 g −1 . The obtained microspheres show meatball-like morphology aggregated by the carbon-coated LiFePO 4 nanoparticles . The electrochemical impedance spectra (EIS) results indicate that carbon coating can effectively enhance both of the electronic and ionic conductivities for LiFePO 4 /C microspheres. The Li-ion diffusion coefficient of the LiFePO 4 /C microspheres calculated from the cyclic voltammetry (CV) curves is ∼6.25 × 10 −9 cm 2 s −1 . The electrochemical performance can achieve about 100 and 90 mAh g −1 at 5C and 10C charge/discharge rates, respectively. As cathode material , the as-prepared LiFePO 4 /C microspheres show excellent rate capability and cycle stability, promising for high power lithium-ion batteries.
研究领域:
材料科学
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电化学
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能源存储
·
纳米材料
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功能材料
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固态化学
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电池技术
✓ 已验证
DOI
高影响因子
Journal of Materials Chemistry A
·
2013
·Vol. 1
·期 35
·10429-10435
·
IF 0
Peng Yan,Lei Lu,Xiao-min Liu,Yin Cao,Zhi-peng Zhang,Hui Yang,Xiao-dong Shen
A novel, economic and scalable method is proposed in this context using an impinging jet reactor to continuously precipitate FePO4 (FP) nanoparticles with high purity. The LiFePO4/C (LFP/C) nano-composites synthesized from the FP, lithium and carbon sources show fast charge capability and excellent power performance. The generated FP and LFP/C are characterized with X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM) and inductively coupled plasma (ICP) spectrometry. The LFP/C nano-composites are cycled at various C-rates to explore the electrochemical performance. When the pH of the working solution is 1.3, the molar ratio of Fe to P equals 1 in the obtained amorphous FP. In addition, the precipitation mechanism is discussed. Compared to the amorphous FP, the hexagonal FP obtained after calcining the former one is preferred to synthesize high power LFP/C. It is proved that 2 mol% excess LiOH is needed to compensate for the possible loss of Li during calcination. With 4.4 wt% of in situ carbon coating, the LFP/C nano-composites exhibit 145 mA h g−1 at 10 C (1.7 A g−1, 6 min) charge (without floating charge) and discharge, without obvious capacity loss up to 100 cycles, which is among the best high power performances reported so far. This strategy offers an inexpensive and easy control method to mass-produce high quality LFP/C nano-composites which might be suitable for powering hybrid electric vehicles and plug-in hybrid electric vehicles.
研究领域:
材料科学
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电化学
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能源技术
✓ 已验证
产品关联
DOI
JOM
·
2024
·Vol. 76
·期 8
·4169-4178
·
IF 2.1
He Jie,Liu Jiaming,Yu Xiuyuan,Yang Chao,Liu Qingsheng
LiFePO 4 has become a mainstream cathode material, owing to its good safety and low price. However, its intrinsic limitations in terms of electronic and ionic conductivities hinder its further advancements. To overcome this challenge, element doping has been explored to enhance its conductivity. Here, Na and F co-doped LiFePO 4 /C was successfully synthesized via a carbothermic method. Structural characterization techniques were employed to confirm the formation of Li 0.97 Na 0.03 FePO 3.97 F 0.03 with controllable particle sizes. The incorporation of Na and F ions into the LiFePO 4 lattice results in a reduction of the Li-O bond energy. This decrease in bond energy facilitates the extraction and insertion of lithium ions during the charge and discharge processes, subsequently improving the overall kinetics of lithium-ion diffusion. Simultaneously, lattice distortion induced by doping led to charge compensation and accelerated Li + migration. Benefiting from the enhancement of intrinsic conductivity and Li + diffusivity, the specific capacitance of the co-doped LiFePO 4 /C cathode material was found to be 160 and 110 mAh g −1 at 0.1 and 5 C, respectively. Further, density functional theory calculations showed that Na/F co-doping enhanced the structural evolution in the material and increased free carrier concentration in LiFePO 4 . This work demonstrates that synergistic Na and F co-doping can optimize the rate performance of LiFePO 4 by enhancing intrinsic conductivity and Li + diffusivity, suggesting promising applications of the co-doped LiFePO 4 /C in high-power lithium-ion batteries for electric vehicles and grid-level energy storage systems.
研究领域:
材料科学
·
电化学
✓ 已验证
DOI
高影响因子
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