ELECTROCHIMICA ACTA
·
2019
·
IF 5.383
Hui Zhuang,Yubo Bao,Yake Nie,Yunxian Qian,Yuanfu Deng,Guohua Chen
To overcome the problems faced by the preparation of high-performance LiFe 0.5 Mn 0.5 PO 4 /C cathode material for commercial application in large scale, such as complicated procedures in the synthesis process and/or low volumetric energy density of nanometer-sized sample, herein, micro-agglomerated LiFe 0.5 Mn 0.5 PO 4 /C is prepared by a facile surfactant-assisted solid-state route. A composite carbon source and controllable pre-calcining process are used for achieving the homogenous carbon coating, interconnected pores and uniform particle size distribution . X -ray powder diffraction, Raman spectrum , N 2 -adsorpotion-desorpotion, scanning/transmission electron microscopy and elemental analysis confirm the microstructure and accurate composition of the as-prepared samples. It is found that the composite source not only increases the homogeneity of the carbon coating layer and the pore-forming ability, but also contributes to inhibiting the size growth of the primary particles. Meanwhile, the suitable pre-calcining time can improve the specific surface area and optimize the carbon content and pore structure , and thus enhance the tap density of the as-prepared material. The typical LiFe 0.5 Mn 0.5 PO 4 /C sample with carbon content of 3.50 wt% displays high reversible capacities and good rate capability, with discharge capacities of 155.0, 141.5 and 120.1 mA h g −1 at 0.1, 1.0 and 5.0 C (1 C = 170 mA g −1 ), respectively. Furthermore, the sample exhibits superior cycling performance, with a capacity retention above 98% after 200 cycles at 1.0 and 5.0 C. As a result, this LiFe 0.5 Mn 0.5 PO 4 /C exhibits great potential as a cathode material for high power/energy lithium ion batteries because of its easy synthesis, high specific capacity, good rate capability and cycle stability.
研究领域:
材料科学
·
能源存储与转换
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DOI
高影响因子
JOURNAL OF POWER SOURCES
·
2024
·
IF 8.1
Hong Chen,Yuchen Wu,Hanyu Xu,Jiaqing Zhao,Ji Wang,Chaojie Ren,Chao Zhao,Ruizhi Yang
The limited electron and ionic conductivity, along with the sluggish kinetics caused by the Jahn-Teller effect of Mn 3+ , impose constraints on the electrochemical performance of LiFe x Mn 1-x PO 4 . Herein, the surface of LiFe 0.5 Mn 0.5 PO 4 (LFMP) is modified with a F-doped carbon using the solvothermal and calcination methods. The incorporation of F-doped carbon coating, along with the formation of interfacial F-Li, F-Fe and F-Mn bonds between the carbon layer and LFMP nanoparticles, significantly mitigates charge transfer resistance, facilitates rapid electron transfer, as well as enhances Li + diffusion kinetics. The LFMP@C-F2 cathode prepared in this study exhibits an unexceptionable capacity retention of 90.5 % after 300 cycles at a low rate of 0.2C and a capacity retention of 78.8 % over 1000 cycles at a high rate of 1C. When incorporated into the solid battery configuration (Li/PEO-LATP CSE/LFMP@C-F2), it exhibits an initial discharge specific capacity of 148 mAh g −1 and maintains a capacity retention of 85.8 % after 60 cycles at 0.1C, thereby offering an innovative approach to enhance the performance of LFMP in terms of cycling stability and rate capacity in lithium-ion batteries, as well as to apply LFMP into solid-state lithium batteries.
研究领域:
材料科学
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电化学
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能源存储
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产品关联
DOI
高影响因子
JOURNAL OF ALLOYS AND COMPOUNDS
·
2019
·
IF 4.175
Ziwei Deng,Qi Wang,Dachun Peng,Hongbo Liu,Yuxi Chen
Olivine-type LiFe x Mn 1- x PO 4 /C cathode materials are of great interest for lithium-ion batteries because of their higher lithium ion intercalation potential compared with that of LiFePO 4 . Two types of LiFe 0.5 Mn 0.5 PO 4 /C nanorods with different sizes and crystal structures were synthesized through a facile glycol-based solvothermal process with different precursor feeding sequences. The microstructural investigation revealed that the size and structure of the LiFe 0.5 Mn 0.5 PO 4 nanorods can be tuned by nucleation and crystal growth rates of the intermediate precipitates, which can be controlled by precursor feeding sequence. The LiFe 0.5 Mn 0.5 PO 4 nanorods obtained through the first feeding sequence (a solution of transition metal salts was added dropwise into the solution mixture of LiOH and H 3 PO 4 ) exhibited less exposure of the (010) crystal faces and had bigger sizes compared with those of the LiFe 0.5 Mn 0.5 PO 4 nanorods obtained through the second feeding sequence (a LiOH solution was added dropwise into the solution mixture of H 3 PO 4 and transition metal salts). Electrochemical investigations indicated that the LiFe 0.5 Mn 0.5 PO 4 nanorods obtained through the second feeding sequence showed substantially improved electrochemical performance, in which the discharge capacities reached 157 and 119 mAh g −1 at 0.2 and 5 C, respectively. Furthermore, a capacity retention of 89% was obtained after 500 cycles at 1 C, demonstrating excellent cyclic stability.
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
ChemSusChem
·
2025
·
IF 6.6
Danfeng Zhang,Jiaxiu Sun,Zhiqi Ren,Yuhang Wang,Zongsheng Qiu,Jianwen Yang,Yongbin He,Meng Qin,Fei Sun,Lianming Zhang,Bin Huang,Yanwei Li,Shunhua Xiao
The application of LiFe 1− y Mn y PO 4 (0 < y < 1) cathode materials with high voltage and high specific energy for lithium-ion batteries is restrained by capacity decay, structure degradation, and low Li + /electronic conductivity, especially at high temperature. In this study, the Nb 5+ -doped olivine-structured LiFe 0.5 Mn 0.5− x Nb x PO 4 (LFMP- x Nb, x = 0%, 0.5%, 1%, 2%, and 3%) are synthesized and characterized using X-ray diffraction, scanning electron microscopy, transmission electron microscopy, infrared spectroscopy, X-ray photoelectron spectroscopy, and electrochemical techniques. The lattice parameters ( a , b , c , and V ), P O and TM O bond lengths, and particle size are reduced with Nb doping, and the structure stability, electronic/Li + transport rate, and electrochemical performances are improved. The preferred LFMP-1%Nb sample delivers an initial discharge specific capacity of 160.57 mAh g −1 at 0.1 C with a coulombic efficiency of 91.38%, and a specific capacity of 91.23 mAh g −1 at 10 C, and a capacity retention rate of 78.71% with a residual capacity of 106.10 mAh g −1 after 1000 cycles at 1 C. Especially at 55 °C temperature, it can give a discharge specific capacity of 142.9 mAh g −1 and a capacity retention rate of 73.14% after 1000 cycles at 1 C. Graphical Nb 5+ doping shortens the TM O and P O bond lengths, suppressing the Jahn–Teller aberration and the solvation of Mn 2+ ions. Consequently, after 1000 charge-discharge cycles at 1 C rate under 25 °C and 55 o C temperatures, the LiFe 0.5 Mn 0.49 PO 4 −1%Nb cathode material exhibits capacity retention rates of 78.71% and 73.14%, respectively.
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产品关联
DOI
PubMed
高影响因子
Journal of Materials Chemistry A
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2014
·Vol. 3
·期 3
·996-1004
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IF 0
Xue Zhou,Ye Xie,Yuanfu Deng,Xusong Qin,Guohua Chen
The rate performance of LiMnPO4-based materials is further improved via synergistic strategies including a surfactant-assisted solid state method, Fe-substitution and carbon-coating. The surfactant-assisted solid state strategy effectively decreases the primary particle size of the cathode material, which can greatly shorten the diffusion distance of lithium ions. The Fe-substitution improves the effectiveness of Li+ insertion/extraction reactions in the solid phase. The uniform carbon coating layer and the conductive networks provided by the carbon between the nanoparticles ensure the continuous conductivity by the nanoparticles. As a consequence of the synergistic effects, the as prepared LiFe0.5Mn0.5PO4 sample with 6.10 wt% carbon exhibits high specific capacities and superior rate performance with discharge capacities of 155.0, 140.9 and 121 mA h g−1 at 0.1, 1 and 5 C (1 C = 170 mA g−1), respectively. Meanwhile, it shows stable cycling stability at both room temperature (25 °C, 94.8% and 90.8% capacity retention after 500 cycles at 1 and 5 C rates, respectively) and elevated temperature (55 °C, 89.2% capacity retention after 300 cycles at 5 C rate). This material may have great potential application in advanced Li-ion batteries.
研究领域:
材料科学
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电化学
✓ 已验证
产品关联
DOI
危险品化学品经营许可证（带存储）