ELECTROCHIMICA ACTA
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2022
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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
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电化学
✓ 已验证
DOI
高影响因子
JOURNAL OF COLLOID AND INTERFACE SCIENCE
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2024
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IF 9.4
Jie Wang,Qiming Liu,Shiyue Cao,Huijuan Zhu,Yilin Wang
Na 3 V 2 (PO 4 ) 2 F 3 (NVPF), recognized for its Na superionic conductor architecture, emerges as a promising candidate among polyanion-type cathodes for sodium ion batteries (SIBs). However, its adoption in practical applications faces obstacles due to its inherently low electronic conductivity. To address this challenge, we employ a binary co-doped strategy to design Na 3.3 K 0.2 V 1.5 Mg 0.5 (PO 4 ) 2 F 3 cathode with nitrogen-doped carbon (NC) coating layer. This configuration enhances electronic conductivity and reduces diffusion barriers for sodium ion (Na + ). The strategy of incorporating nitrogen-doped carbon coating not only facilitates the formation of a porous structure but also introduces additional defects and active sites. Such modifications accelerate the reaction kinetics and augment electrolyte interaction through an expanded specific surface area, thus streamlining the electrochemical process. Concurrently, strategic heteroatom substitution leads to a more efficient engagement of Na + in the electrochemical activities, thereby bolstering the cathode's structural integrity. The vanadium fluorophosphate Na 3.3 K 0.2 V 1.5 Mg 0.5 (PO 4 ) 2 F 3 @NC exhibits an electrochemical performance, including a high discharge specific capacity of 124.3 mA h g −1 at 0.1C, a long lifespan of 1000 cycles with a capacity retention of 93.1 % at 10C, and a rate property of 73.2 mA h g −1 at 20C. This research provides a method for preparing binary doped NVPF for energy storage electrochemistry.
研究领域:
材料科学
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能源存储
✓ 已验证
产品关联
DOI
PubMed
高影响因子
Journal of Energy Chemistry
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2021
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IF 9.676
Chuan Guo,Jianwei Yang,Zhiyuan Cui,Shuo Qi,Qianqian Peng,Weiwei Sun,Li-Ping Lv,Yi Xu,Yong Wang,Shuangqiang Chen
With great superiorities in energy density, rate capability and structural stability, Na 3 V 2 (PO 4 ) 2 F 3 (NVPF) has attracted much attentions as cathode of sodium ion battery (SIB), but it also faces challenges on its poor intrinsic electronic conductivity and the controversial de/sodiation mechanism. Herein, a series of Zr-doped NVPF coated by N-doped carbon layer (~5 nm in thickness, homogenously) materials are fabricated by a sol–gel method, and the optimized heteroatom-doping amounts of Zr and N doping improve intrinsic properties on enlarging lattice distance and enhancing electronic conductivity, respectively. Specifically, among all samples of Na 3 V 2− x Zr x (PO 4 ) 2 F 3 /NC (NVPF-Zr- x /NC, x = 0, 0.01, 0.02, 0.05, and 0.1), the optimized electrode of NVPF-Zr-0.02/NC delivers high reversible capacities (119.2 mAh g −1 at 0.5 C), superior rate capability (98.1 mA h g −1 at 20 C) and excellent cycling performance. The structural evolution of NVPF-Zr-0.02/NC electrode, in-situ monitored by X-ray diffractometer, follows a step-wise Na-extraction/intercalation mechanism with reversible multi-phase changes, not just a solid-solution-reaction one. Full cells of NVPF-Zr-0.02/NC//hard carbon demonstrate high capacity (99.8 mA h g −1 at 0.5 C), high out-put voltage (3.5 V) and good cycling stability. This work is favorable to accelerate the development of high-performance cathode materials and explore possible redox reaction mechanisms of SIBs.
研究领域:
材料科学
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电化学
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能源存储与转换
✓ 已验证
DOI
高影响因子
ACS Applied Energy Materials
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2023
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IF 6.4
Meng Wang,Yingshuai Wang,Yuhang Xin,Qi Liu,Feng Wu,Hongcai Gao
Na super ionic conductor (NASICON)-type Na3V2(PO4)2F3 (NVPF) has been regarded as a prospective candidate of cathode materials for sodium-ion batteries due to its excellent structural stability, relatively high capacity and working voltage. However, the poor cyclability and rate capability, resulting from its low intrinsic electronic conductivity, have become a serious obstacle to their practical large-scale application. In this work, N-doped carbon coated NVPF composites (NVPF@NC) were successfully synthesized via a simple sol–gel method, in which low-cost polyvinylpyrrolidone was introduced as a nitrogen source. After high-temperature pyrolysis, a highly conductive N-doped carbon layer was in-situ constructed on the particle surface to enhance the sodium storage performance of NVPF. The optimized NVPF@NC cathode delivered high reversible capacity, excellent rate capability and long-term cycle life compared to pristine NVPF@C. The remarkable electrochemical performance of NVPF@NC cathode benefits from the modification strategy of introducing a heteroatom-doped carbon layer, triggering the formation of extrinsic defects and active sites in the N-doped amorphous carbon layer, which greatly enhances the electrical conductivity and the diffusion rate of sodium ions. This work provides a facile and effective approach for the preparation of N-doped carbon coated NVPF with remarkable sodium storage properties, which could be extended to other electrode materials electrochemical for energy storage.
研究领域:
材料科学
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能量存储
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电化学
✓ 已验证
DOI
高影响因子
危险品化学品经营许可证（带存储）