Journal of Materials Chemistry A
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2024
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IF 10.7
Xinyu Li,Sheng Dai,Qinlong Chen,Hongyan Mao,Huilin Pan
The air stability of electrode materials is a crucial factor for their practical application in rechargeable batteries. Na4Fe3(PO4)2P2O7 (NFPP) is a cathode material for sodium-ion batteries that has garnered increasing attention for long-life stationary energy storage. However, there is limited understanding regarding the air stability of NFPP. Here, we systematically investigated the chemical and structural stability and degradation mechanism of NFPP upon heating in ambient air. It is revealed that the extraction of Na+, Fe2+, and PO43− ions from NFPP is induced by moisture in ambient air, resulting in the formation of a composite amorphous phase and Na3PO4 small crystalline clusters on the NFPP surface. In addition, we observed a gradual enrichment of crystalline Na3PO4 through X-ray diffraction analysis during prolonged air exposure. The degraded NFPP leads to significantly reduced capacity and enlarged charge and discharge polarization. We demonstrate that optimal re-calcination under an inert atmosphere can effectively restore the mildly deteriorated NFPP material in terms of both structure and electrochemical performance. This research provides valuable insights for practical applications of polyanion cathodes in sodium-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
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产品关联
DOI
高影响因子
International Journal of Minerals Metallurgy and Materials
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2026
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IF 8.8
Wang Ziyan,Zhou Meng,Zhang Rongzheng,Zou Yuening,Zhang Sikai,An Wen,Hu Hai,Huang Zhifeng,Ye Zhongqiang,Liu Li
The Na 4 Fe 3 (PO 4 ) 2 P 2 O 7 /C composite (NFPP-E) featuring a highly graphitized N- and P-co-doped carbon coating and hierarchical pore structure was successfully synthesized using a facile ball-milling-calcination approach. Ethylenediamine tetra(methylene phosphonic acid) (EDTMPA) acts as a multifunctional precursor and concurrently serves as a chelating, phosphorus, carbon, nitrogen, and pore-forming agent. The unique “phosphorus-catalyzed graphitization” effect during EDTMPA pyrolysis plays a pivotal role; the released active phosphorus oxides facilitate the ordered transformation of the carbon matrix, thereby yielding a highly graphitized N- and P-co-doped carbon coating with a low defect density. Electrochemical measurements demonstrated significant performance enhancements of NFPP-E relative to the sample prepared with conventional NH 4 H 2 PO 4 . Specifically, NFPP-E delivered a high reversible capacity of 103.09 mAh·g −1 at 0.1 C (1 C = 129 mA·g −1 ) and retained 77.41 mAh·g −1 even at an elevated rate of 10 C, demonstrating excellent rate capability. Furthermore, it exhibited superior long-term cycling stability, with a capacity retention rate of 94.9% after 500 cycles at 1 C. When assembled into a full cell with hard carbon as the anode, the NFPP-E achieved a capacity retention rate of 92.74% over 200 cycles, highlighting its great potential for practical applications. This study not only uncovers the universal principle for regulating the structure and properties of carbon layers via the “phosphorus-catalyzed graphitization” mechanism using organic phosphonic acid precursors but also offers a novel strategy for the development of high-performance and low-cost cathode materials for sodium-ion batteries.
✓ 已验证
DOI
高影响因子
Materials
·
2024
·Vol. 17
·期 11
·2679
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IF 3.1
Tongtong Chen,Xianying Han,Mengling Jie,Zhiwu Guo,Jiangang Li,Xiangming He
Na4Fe3(PO4)2P2O7/C (NFPP) is a promising cathode material for sodium-ion batteries, but its electrochemical performance is heavily impeded by its low electronic conductivity. To address this, pure-phase Mo6+-doped Na4Fe3−xMox(PO4)2P2O7/C (Mox-NFPP, x = 0, 0.05, 0.10, 0.15) with the Pn21a space group is successfully synthesized through spray drying and annealing methods. Density functional theory (DFT) calculations reveal that Mo6+doping facilitates the transition of electrons from the valence to the conduction band, thus enhancing the intrinsic electron conductivity of Mox-NFPP. With an optimal Mo6+doping level of x = 0.10, Mo0.10-NFPP exhibits lower charge transfer resistance, higher sodium-ion diffusion coefficients, and superior rate performance. As a result, the Mo0.10-NFPP cathode offers an initial discharge capacity of up to 123.9 mAh g−1at 0.1 C, nearly reaching its theoretical capacity. Even at a high rate of 10 C, it delivers a high discharge capacity of 86.09 mAh g−1, maintaining 96.18% of its capacity after 500 cycles. This research presents a new and straightforward strategy to enhance the electrochemical performance of NFPP cathode materials for sodium-ion batteries.
研究领域:
材料科学
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电化学
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DOI
高影响因子
JOURNAL OF COLLOID AND INTERFACE SCIENCE
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2024
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IF 9.4
Fan Wu,He Ma,Xin Ye,Shaoyang Wu,Haodong Zhang,Kang Liang,Jianbin Li,Yurong Ren,Peng Wei
Mixed iron-based phosphate Na 4 Fe 3 (PO 4 ) 2 P 2 O 7 /C (NFPP) has gradually emerged as a promising cathode material for sodium-ion batteries (SIBs) owing to its affordability and convenient preparation. However, poor electrical conductivity and inadequate sodium-ion diffusion limit the exertion of its electrochemical properties. Herein, a structural modulation strategy based on Cd doping is applied to NFPP to address the above limitations. In situ X-ray diffraction analysis reveals that Cd-doped NFPP (NFCPP) undergoes an incomplete solid-solution reaction driven by Fe 2+ /Fe 3+ redox. Cd doping effectively stabilises the crystal structure, resulting in a minimal 1 % change in unit cell volume during cycling. Density of state calculations indicate that Cd doping reduces the band gap, increases the local electron density and significantly improves electron conductivity. Benefitting from the enhanced electrochemical kinetics and intercalation pseudocapacitance, the optimised Na 4 Fe 2.91 Cd 0.09 (PO 4 ) 2 P 2 O 7 /C (NFCPP@3%) exhibits exceptional rate performance (capacity of 62 mAh/g at 20 C) and ultra-long cycling life (82.7 % after 6000 cycles at 20 C). A full SIB prepared using NFCPP@3% and hard carbon, display a 91 % capacity retention rate at a current density of 130 mA g −1 over 200 cycles. This work demonstrates that doping can effectively enhance electrochemical performance and offers insights into future development of SIBs.
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
ELECTROCHIMICA ACTA
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2026
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IF 5.8
Sihao Bi,Xiaowen Dai,Xiaolong Wang,Zhengran Wang,Jia Man,Shuo Meng,Jinkui Feng
Sodium-ion batteries (SIBs) show great potential for energy storage, but currently suffer from low cycling stability and volume expansion in the electrode. This study proposes a composite cathode material composed of sodium iron pyrophosphate (NFPP) and MXene via electrostatic self-assembly. The crumpled MXene nanosheets serve as conductive scaffolds, uniformly encapsulating NFPP particles, which effectively mitigates volume expansion and boosts charge transport kinetics by MXene/NFPP hetero-structure. The MXene nanosheets effectively prevent direct contact between NFPP particles and the electrolyte, thereby suppressing NFPP dissolution in the electrolyte and improving cycling stability. And the NFPP/MXene composite cathode surface morphology remained relatively smooth after cycling, and alleviating volume expansion. Furthermore, to prevent the surface of MXene self-restacking, the MXene ratio in the NFPP/MXene composite was optimized. The NFPP/MXene-5 cathode demonstrates superior cycling durability, delivering a specific capacity of 62.7 mAh·g −1 after 1,000 cycles at 1 A·g −1 , accompanied by 76.9% capacity retention. Experimental tests and theoretical calculations confirm the composite’s superior adsorption capability and high-rate performance, providing valuable insights for designing high-rate and stable sodium ion batteries.
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DOI
高影响因子
ADVANCED MATERIALS
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2025
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IF 26.8
Sike Xie,Yujie Huang,Yanjian Xie,Wei Zhang,Yijian Zhong,Zhihao Liu,Zhixin Liang,Jintao Qi,Yangyang Huang,Jian Peng,Shaoming Huang
Sodium metal anodes (SMAs) are pivotal for high-energy-density batteries but suffer from uncontrolled dendrite growth and interfacial instability caused by infinite volume expansion and a fragile solid electrolyte interphase (SEI). Herein, an innovative strategy is proposed, in which a p-block matrix is in-situ formed from NiTe 2 nanocrystals onto N-doped carbon hollow microspheres (NiTe 2 @NC) during electrochemical activation to overcome these challenges. The p-block matrix with sodiophilic Na 2 Te and conductive metallic nickel effectively reduces the nucleation barrier and establishes bi-continuous ion/electron conduction networks, guiding uniform Na plating. Critically, Na 2 Te dominates the formation of a gradient inorganic-rich SEI with high Young's modulus and low Na⁺ diffusion barrier, significantly enhancing mechanical resilience and ion transport kinetics. Consequently, the NiTe 2 @NC electrode achieves exceptional cyclability (1,000 cycles at 1.0 mA cm − 2 /1.0 mAh cm − 2 with an average Coulombic efficiency of 99.79%). When configured in full-cells with a Na 4 Fe 3 (PO 4 ) 2 P 2 O 7 cathode, it maintains the capacity retention of over 96.1% (103.9 mAh g − 1 ) after 1,200 cycles at 10.0 C. Critically, the full-cell maintains superior electrochemical resilience with high discharge-capacity and >90% retention at low-temperatures (−20 and −40 °C), demonstrating exceptional practicality for sodium metal batteries. This work establishes a new paradigm for stabilizing reactive metal anodes via in-situ-constructed multifunctional interfaces.
研究领域:
储能与转换
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电化学
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材料科学
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电池技术
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纳米材料
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产品关联
DOI
PubMed
高影响因子
CHEMICAL ENGINEERING JOURNAL
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2024
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IF 13.3
Yuhang Xin,Qianchen Wang,Yingshuai Wang,Meng Wang,Feng Wu,Hongcai Gao
As an inexpensive and environmentally-friendly cathode for sodium-ion batteries, Na 4 Fe 3 (PO 4 ) 2 P 2 O 7 (NFPP) is considered to be a promising candidate for practical applications. However, the theoretical capacity of NFPP is limited to 129 mAh g −1 , due to the fact that only three electrons can be participated in the reaction during the charge/discharge process. Herein, the critical role of cobalt and manganese in elevating the energy density of the pristine NFPP structure was investigated, and Na 4 Co 0.5 Mn 0.5 Fe 2 (PO 4 ) 2 P 2 O 7 (NCMFPP) is prepared in order to trigger a redox reaction with 3.5 electrons during the charge/discharge process. It is found that the NCMFPP can provide a high initial discharge capacity of 139 mAh g −1 at 0.1C (1C = 129 mA g −1 ), with an excellent rate capacity (75 mAh g −1 at 10C) and a remarkable long cycling stability with a capacity retention of 65.2 % after 2000 cycles at 10C. The reaction of the Mn 3+ /Mn 4+ redox couple was characterized by X-ray photoelectron spectroscopy analysis during the charge/discharge process. These results verified the effectiveness of cobalt and manganese in elevating the energy density of NFPP as a cathode as a cathode material for low-cost sodium-ion batteries.
研究领域:
材料科学
·
电化学
✓ 已验证
产品关联
DOI
高影响因子
危险品化学品经营许可证（带存储）