ELECTROCHIMICA ACTA
·
2022
·
IF 7.336
Xiaoli Yi,Hongyue Luo,Yongmao Zhou,Shihao Feng,Jiexi Wang,Zhixing Wang,Jianguo Duan,Ding Wang,Huajun Guo,Guochun Yan
Na 3 V 2 (PO 4 ) 2 F 3 is considered as one of the most promising cathode materials for sodium-ion batteries (SIBs). However, the low electronic conductivity of this material severely restricts its electrochemical performance. Herein, Cr-doped Na 3 V 2 (PO 4 ) 2 F 3 /C material was synthesized by a simple sol-gel method, and the effects of Cr 3+ doping on the structure, morphology and electrochemical performance were systematically investigated. The optimized material Na 3 V 2-x Cr x (PO 4 ) 2 F 3 /C (x = 0.05) exhibits high initial discharge capacity of 101.9 mAh g −1 at 10 C and keep a capacity retention of 68.7 % after 1000 cycles. The improved electrochemical performance can be attributed to the higher crystallinity, improved intrinsic electronic conductivity and sodium ion diffusion coefficient due to the doped Cr 3+ , which accelerates the electron transport and charge transfer rate. The optimized Cr-doped Na 3 V 2 (PO 4 ) 3 F 3 /C material obtained in this work can promote the practical application of Na 3 V 2 (PO 4 ) 3 F 3 cathode.
研究领域:
材料科学
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电化学
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能源存储
✓ 已验证
DOI
高影响因子
RSC Advances
·
2019
·Vol. 9
·期 53
·30628-30636
·
IF 3.049
Mingxue Wang,Xiaobing Huang,Haiyan Wang,Tao Zhou,Huasheng Xie,Yurong Ren
Na3V2(PO4)2F3 (NVPF) with NASCION (Na superionic conductor) is recognized as a potential cathode material owing to its high theoretical capacity. However, the electronic conductivity of NVPF is much lower than its ionic conductivity, which seriously affects the properties of this material. The carbon layer can be used as the conductive medium to enhance the conductivity of NVPF. In this study, we propose a single-step solid-state reaction method based on mechanical activation with pitch as the carbon source to synthesize NVPF/C composites. The crystallographic structure and morphology of all as-prepared samples were investigated by XRD, Raman spectroscopy, BET measurement, thermal analysis, SEM and TEM. Furthermore, the electrochemical performance and kinetic properties were analyzed by CV, galvanostatic charge–discharge and EIS tests. These tests outcomes demonstrated that the NVPF/C-2 composite with a carbon content of 12.14 wt% showed an excellent rate performance and cycle stability. It presented reversible capacities of 103 and 95 mA h g−1 at 0.2 and 10C, respectively, and an outstanding retention of 91.9% after 500 cycles at 5C. These excellent properties of the NVPF/C-2 composite are attributed to its high ion diffusion coefficient and small charge transfer impedance.
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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无机固体化学
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纳米材料
✓ 已验证
DOI
高影响因子
ELECTROCHIMICA ACTA
·
2022
·
IF 7.336
Wenjie Zhao,Weigang Wang,Guorong Hu,Ke Du,Zhongdong Peng,Xudong Zhang,Huan Li,Zijun Fang,Yanbing Cao
Porous Na 3 V 2 (PO 4 ) 2 F 3 (NVPF) with micro-nano structure was prepared by a simple deep-eutectic solvent method with good crystallinity and uniformity. Surface modification was used to produce carbon-coated NVPF (NVPF/C). The unique morphologic architecture and surface modification improve the structural stability and interfacial chemical stability of NVPF, ensuring the excellent rate performance and cycle stability of NVPF/C. At 120 °C, secondary microspheres NVPF composed of nanoparticles are successfully synthesized. By liquid phase reaction in a deep-eutectic solvent X-ray diffraction analysis reveals that these microspheres have good crystallinity . The NVPF/C with an amorphous fluorocarbon coating layer is constructed by pyrolysis of polytetrafluoroethylene (PTFE). The mesoporous structure and the existence of the coating layer are clearly obvious under the high-definition transmission electron microscope. The amorphous fluorocarbon layer enhances the reversibility and transmission ability of Na + , improving the electrochemical kinetics. And the obtained NVPF/C cathode material displays high-rate performance. The as-prepared NVPF/C-F composites with 6 %wt coating of PTFE have a specific capacity of 110.6 mAh g −1 at 10 C, 106.4 mAh g −1 at 20 C and 94.6 mAh g −1 at 50 C. The capacity retention rate is 90.4 % after 700 cycles at 20 C. This research provides a facile and inexpensive approach for getting high-rate performance sodium-ion battery cathode materials.
研究领域:
材料科学
·
电化学
✓ 已验证
DOI
高影响因子
CERAMICS INTERNATIONAL
·
2020
·
IF 3.83
Mingxue Wang,Kun Wang,Xiaobing Huang,Tao Zhou,Huasheng Xie,Yurong Ren
To improve the intrinsic electronic conductivity of Na 3 V 2 (PO 4 ) 2 F 3 (NVPF), zirconium (Zr) was introduced into the NVPF/C compound through a carbothermal reduction reaction with citric acid as the carbon source. The effects of Zr 4+ doping on the crystal structure and morphology of the as-prepared materials were analyzed. Electrochemical and kinetic properties of the samples were investigated by galvanostatic charge-discharge, CV and EIS test. It is confirmed that moderate Zr 4+ doping can improve the electrochemical performance of NVPF. Among all Na 3 V 2-x Zr x (PO 4 ) 2 F 3 /C (x = 0, 0.01, 0.05, 0.1) samples, Na 3 V 1·95 Zr 0·05 (PO 4 ) 2 F 3 /C shows the best rate and cycle performance. It exhibits the highest specific capacity of 121.8 and 110.3 mAh/g at 0.2 and 10 C, respectively, and maintains a capacity retention of approximately 83.6% after 1000 cycles at 5 C. The kinetic properties results show that the excellent electrochemical performance of Na 3 V 1·95 Zr 0·05 (PO 4 ) 2 F 3 /C can be attributed to the increase in electronic conductivity and ion diffusion coefficient .
研究领域:
材料科学
·
电化学
·
储能
✓ 已验证
DOI
高影响因子
CHEMISTRY OF MATERIALS
·
2025
·
IF 7
Shaokang Guo,Jian Peng,Neeraj Sharma,Jiaqi Pan,Yi Liao,Xinhao An,Hanchi Li,Zhisong Ge,Chunliang Zhou,Wen Liang Tan,Junnan Liu
Na3V2(PO4)2F3 (NVPF) has been considered as a promising NASICON-type (sodium superionic conductor) cathode material for sodium-ion batteries (SIBs). However, their development has been limited by poor electronic conductivity. To address this issue, a series of Sc-doped carbon-coated Na3V2–xScx(PO4)2F3/C, x = 0, 0.02, 0.04, 0.06, 0.08, and 0.1 were synthesized by the sol–gel method. Sc is found to partially stabilize the crystalline framework, reduce deformation during Na+ insertion/extraction, and reduce polarization, which in turn impacts the diffusion of Na+ ions in the crystal lattice. The optimized NVPF has good electronic conductivity and cycling stability; in particular, the NVSPF/C-0.04 electrode exhibits the highest discharge specific capacity (125 mAh g–1 at 0.2 C), excellent rate performance (87 mAh g–1 at 30 C), and outstanding cycling performance (90% capacity retention after 1000 cycles at 10 C and 94% capacity retention after 100 cycles at 1 C). Density functional theory shows that the Sc-doping effectively improves the electronic conductivity of the NVPF. In situ and operando synchrotron XRD data show that the NVSPF/C-0.04 electrode undergoes phase transitions during charge/discharge at 0.2 and 2 C and indicates the reason for the capacity decay at 5 C. Finally, the NVSPF/C-0.04//HC (hard carbon) full cell performs with a good discharge specific capacity (112 mAh g–1 at 1 C). This study presents a feasible approach to developing high-performance cathode materials that can be used in SIBs, and it holds great potential for the future advancement of SIBs.
研究领域:
材料科学
·
电化学
✓ 已验证
产品关联
DOI
高影响因子
Frontiers in Chemistry
·
2019
·
IF 3.782
Hao Guo,Yong Hu,Xiaoping Zhang,Rongliang Zhang,Dong Hou,Yulei Sui,Ling Wu
In this paper, we report a facile one-step hydrothermal method to synthesize tetragonal Na3V2(PO4)2F3@C particles which are connected by carbon nanotubes (CNTs) networks, using water as hydrothermal solvents. In this strategy, the reduction and crystallization of materials are carried out in the hydrothermal process (180°C, 12 h), no additional heat treatment is required. The well-crystallized Na3V2(PO4)2F3 tetragonal grains (5–10 μm) are coated with amorphous nano-carbon and connected by highly conductive CNTs. The addition of CNTs can not only improve the conductivity of materials but also effectively inhibit the Na3V2(PO4)2F3 grains over growth. The Na3V2(PO4)2F3@C/CNTs composite possesses very flat charge/discharge platforms of 3.6 and 4.1 V. The sample exhibits an initial discharge specific capacity of 120.2 and 74.3 mAh g−1 at 0.1 and 10 C rate, respectively, and shows excellent cyclical stability. The composite owns excellent electrochemical performances owing to the three-dimensional highly conductive network which is co-constructed by the CNTs and nano-carbon coating layer.
研究领域:
材料科学
·
电化学
·
纳米科技
·
能源存储
·
无机化学
✓ 已验证
DOI
高影响因子
危险品化学品经营许可证（带存储）