Small
·
2025
·
IF 12.1
Kai Zhang,Yao Niu,Haiyang Xing,Peifeng Wang,Lingbing Wu,Xianghua Yao,Youlong Xu
Layered transition metal oxide P2-Na 0.7 MnO 2 typically faces challenges such as low potential plateau, phase transitions, and poor rate capability. A cost-effective high-entropy substitution strategy is developed to synthesize P2-Na 0.7 Li 0.02 K 0.02 Fe 0.2 Cu 0.2 La 0.02 Ti 0.02 V 0.02 Mn 0.5 O 2 . The study elucidates that the synergistic influence of substituted elements, specifically Cu 2+ /Cu 3+ and Fe 3+ /Fe 4+ , engenders higher redox potentials, substantially enhancing the potential plateau (the discharge midpoint potential increased from 2.36–3.5 V). The addition of La improves structural stability and conductivity. This high-entropy substitution methodology adeptly mitigates volumetric O2 phase transitions, fostering the formation of a moderate self-regulating P2+“Z” phase. The material's volume change in the second cycle at approximately the same potential (≈2.6 V) is about -0.17%. Notably, Hall effect testing indicates that the material primarily conducts electricity through holes. Both bulk and surface carrier concentrations, as well as mobility, have increased. The conductivity increases up to four times (from 8.43E-06 (S cm −1 ) to 3.49E-05 (S cm −1 )). The material delivers a reversible capacity of 151.8 mAh g −1 at 0.1 C within the range of 1.5–4.5 V, retaining 81.3% of capacity at 1 C after 100 cycles. It retains 97.6% capacity at 1 C after 50 cycles within the range of 2.0–4.2 V.
研究领域:
材料科学
·
电化学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
JOURNAL OF COLLOID AND INTERFACE SCIENCE
·
2024
·
IF 9.4
Pengju Zhang,Junying Weng,Zhengkun Lu,Longchen Li,Bingyang Ji,Minghui Ding,Yiran Sun,Wenyong Yuan,Pengfei Zhou,Hailin Cong
P 2-Na 0.67 Mn 0.67 Ni 0.33 O 2 is a promising cathode material for sodium ion batteries (SIBs) due to its low cost, high theoretical capacity, and non-toxicity. However, it still suffers from unsatisfactory cycling stability mainly incurred by the Jahn-Teller effect of Mn 3+ and electrolyte decomposition on the electrode/electrolyte interface. Herein, the P 2-Na 0.67 Ni 0.33 Mn 0.67 O 2 @PPy (NNMO@PPy) composite applied as cathode materials for SIBs is obtained by introducing conductive polypyrrole (PPy) as coating layer on the P 2-Na 0.67 Ni 0.33 Mn 0.67 O 2 (NNMO) microspheres. Numerous physical characterization methods indicate that the PPy layer was uniformly coated on the surface of NNMO microspheres without change in phase structure and morphology. The PPy coating layer can alleviate Mn dissolution and effectively suppress the side reactions between the electrolyte and electrode during cycling. The optimal NNMO@PPy-9 with 9 wt% PPy delivers a high capacity of 127.4 mAh/g at the current density at 150 mA g −1 , an excellent cyclic stability with high capacity retention of 80.5 % after 300 cycles, and enhanced rate performance (169.3 mAh/g at 15 mA g −1 while 89.8 mAh/g at 600 mA g −1 ). Furthermore, hard carbon (−)//NNMO@PPy-9 (+) full cell delivers a high energy density of 305.1 Wh kg −1 and superior cycling stability with 88.2 % capacity retention after 150 cycles. In-situ X-ray diffraction experiment and electrochemical characterization verify the highly reversible structure evolution and robust P 2-type phase structure of NNMO@PPy-9 for fast and stable Na + diffusion. This effective strategy of using conductive PPy as a coating layer may provide a new insight to modify NNMO surface, improving the cycling stability and rate capability.
研究领域:
材料科学
·
电化学
✓ 已验证
DOI
高影响因子
ADVANCED FUNCTIONAL MATERIALS
·
2023
·Vol. 33
·期 41
·2303812
·
IF 19
Ming-Yuan Shen,Jing-Song Wang,Zhouhong Ren,Tao Wu,Xi Liu,Liwei Chen,Wen-Cui Li,An-Hui Lu
P2-type layered oxide material Na 2/3 Ni 1/3 Mn 2/3 O 2 is a competitive candidate for sodium-ion batteries (SIBs). Nevertheless, it suffers from the strong P2–O2 phase transition during charging to the high voltage regime, rendering drastic volume variations and poor cycling performance. Here, a Quasi-zero strain P2-Na 0.75 Li 0.15 Mg 0.05 Ni 0.1 Mn 0.7 O 2 cathode is synthesized, which reflects the vanishing P2–O2 transition with a volume change as low as 0.49%, thus resulting in the material an excellent cycling performance (83.9% capacity retention after 500 cycles at 5 C). The low-volume strain can be attributed to two aspects: (1) the Mg 2+ riveted in the Na layer can act as a “pillar” to stabilize the crystal structure under the condition of sodium removal, thus restricting the structural changes under high voltage. (2) The entry of Li + into the transition metal (TM) layer can mitigate the electron localization in the highly desodiation state and can effectively immobilize the coordination oxygen atoms, thus suppressing the slip of P2–O2 transition. This study not only provides a new insight of Li and Mg synergetic substitution effect on the structural stability of P2-type cathode, but also an efficient avenue for developing cathode materials of SIBs with ultralow bulk strain.
研究领域:
材料科学
·
电化学
✓ 已验证
产品关联
DOI
高影响因子
Energies
·
2020
·Vol. 13
·期 21
·5729
·
IF 2.702
Chen Cheng,Manling Ding,Tianran Yan,Kehua Dai,Jing Mao,Nian Zhang,Liang Zhang,Jinghua Guo
P2-type sodium layered transition metal oxides have been intensively investigated as promising cathode materials for sodium-ion batteries (SIBs) by virtue of their high specific capacity and high operating voltage. However, they suffer from problems of voltage decay, capacity fading, and structural deterioration, which hinder their practical application. Therefore, a mechanistic understanding of the cationic/anionic redox activity and capacity fading is indispensable for the further improvement of electrochemical performance. Here, a prototype cathode material of P2-type Na0.6Mg0.3Mn0.7O2is comprehensively investigated, which presents both cationic and anionic redox behaviors during the cycling process. By a combination of soft X-ray absorption spectroscopy and electroanalytical methods, we unambiguously reveal that only oxygen redox reaction is involved in the initial charge process, then both oxygen and manganese participate in the charge compensation in the following discharge process. In addition, a gradient distribution of Mn valence state from surface to bulk is disclosed, which could be mainly related to the irreversible oxygen activity during the charge process. Furthermore, we find that the average oxidation state of Mn is reduced upon extended cycles, leading to the noticeable capacity fading. Our results provide deeper insights into the intrinsic cationic/anionic redox mechanism of P2-type materials, which is vital for the rational design and optimization of advanced cathode materials for SIBs.Keywords:sodium-ion batteries;P2-tpye oxides;charge compensation mechanism;X-ray absorption spectroscopy;electronic structure
研究领域:
材料科学
·
电化学
✓ 已验证
DOI
高影响因子
JOURNAL OF COLLOID AND INTERFACE SCIENCE
·
2025
·
IF 9.7
YuKai Hua,MingPei Tan,Ming Liu,Xiao Yu,Donghai Wang,Yong Liu
P2-type layered metal oxides are promising cathode materials for Na-ion batteries (NIBs), but they suffer from Na + /vacancy ordering and P2-O2 phase transitions during charge–discharge processes, resulting in rapid capacity decay and poor rate performance. In this study, a non-equimolar five-component medium-entropy strategy was employed to design a Na 0.67 Ni 0.19 Cu 0.07 Zn 0.07 Mn 0.60 Ti 0.07 O 2 (NNCZMT) material. Unlike equimolar high-entropy designs, Ni and Mn remain as the main components, with Ni providing high capacity through the Ni 2+ /Ni 4+ redox couple and Mn stabilizing the P2 structure. The introduction of Cu 2+ , Zn 2+ , and Ti 4+ , which have slightly larger ionic radii and the same valence states as Ni 2+ and Mn 4+ , respectively, allows for mutual substitution, synergistically promoting a solid-solution reaction and excellent Na + diffusion kinetics. The NNCZMT electrode delivers a high reversible capacity of 110 mAh g −1 at 10 mA g −1 , an initial Coulombic efficiency of 96.8 %, remarkable cycling stability (94.7 % capacity retention after 100 cycles at 200 mA g −1 ), and excellent rate performance (57.2mAh g −1 at 2000 mA g −1 ).
研究领域:
材料科学
·
能源存储技术
✓ 已验证
产品关联
DOI
PubMed
高影响因子
ACS Applied Materials & Interfaces
·
2020
·
IF 8.758
Jinxu Qiu,Boran Chen,Hongying Hou,Xiaojuan Wang,Xiaoyang Liu,Zaihuan Li,Tingting Liu,Ruicong Chen,Shuai Wang,Bao Li,Dongmei Dai,Bao Wang
Because of their high reversible capacity and wide operation voltage window, P2-type layered transition metal oxides are considered as one type of potential cathode candidate for sodium-ion batteries. However, they still suffer from low kinetics, phase degeneration, and ambiguous mechanism of Na+ diffusion. Here, we synthesized a P2-type Na0.6Li0.07Mn0.66Co0.17Ni0.17O2 with a high Na+ diffusion performance by sintering a nanoplate-structural precursor with alkali metal salt and proposed a possible mechanism for improving Na+ diffusion. The as-prepared P2-type layered oxide presents a quasi-hexagon shape and demonstrates a discharge capacity of 87 mAh g–1 at a current density of 875 mA g–1 (5 C rate), twice that of the sample synthesized from a non-nanoplate particle precursor. Rietveld refinement and results of X-ray photoelectron spectroscopy reveal the probable mechanism that the expanded interplanar spacing along the c-axis orientation would facilitate Na+ diffusion during Na+ intercalation/deintercalation processes, and the expanded interplanar spacing may arise from a high oxidation state of transition metal ions.
研究领域:
材料科学
·
电化学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2025
·
IF 13.2
Dawei Chen,Bin He,Shuai Jiang,Xilong Wang,Jie Song,Hao Chen,Dan Xiao,Qian Zhao,Yan Meng,Yujue Wang
Modifications through doping at both the anion site and the transition metal site within P2-type layered oxide cathodes for sodium-ion batteries typically exhibit a synergistic effect, which enhances the performance of these sodium-ion batteries. In this study, a prominent enhancement in the performance of P2-Na 0.67 Ni 0.15 Fe 0.20 Mn 0.65 O 2 (NFM) was achieved through a Zn/F dual-site doping strategy. The doped material P2-Na 0.67 Zn 0.05 Ni 0.15 Fe 0.20 Mn 0.60 O 1.95 F 0.05 (ZNFMF), prepared by co-precipitation followed by solid-state mixing and calcination method, exhibits superior cycling stability and rate performance in electrochemical tests. The doping of Zn/F optimizes the local electronic structure of the material, reduces the valence state of transition metal (TM) elements, enhances the binding energy between lattice oxygen and TM elements, shortens the TM-O bond length, effectively suppresses structural distortion, and improves the cycling performance and structural stability of the material. In-situ XRD and Raman also confirm the improved structural reversibility of the material during the cycling process. The nano-indentation test further confirms that the Young’s modulus and hardness of the ZNFMF is significantly improved compared to NFM during the cycling process. This research successfully improves the structural stability, electrochemical performance, and air stability of the sodium-ion battery cathode material through Zn/F dual-site doping, providing new ideas and methods for the further research and development of sodium-ion battery cathode materials.
研究领域:
材料科学
·
电化学
✓ 已验证
产品关联
DOI
高影响因子
Sustainable Energy & Fuels
·
2024
·Vol. 8
·期 6
·1304-1313
·
IF 5
Hongfeng Liu,Yingshuai Wang,Xiangyu Ding,Yusong Wang,Feng Wu,Hongcai Gao
Layered transition metal oxides are the most promising cathode materials for sodium-ion batteries, however, the cycling stability and rate performance of this type of cathode materials are very limited. Herein, a solid-state reaction method is developed to synthesize micrometer-sized bulk crystals of the P2-type cathode of Na0.85Li0.12Ni0.198Be0.011Mg0.011Mn0.66O2 (denoted as NLNBMMO-5%) via configurational entropy. The high-entropy layered oxide cathode exhibits superior rate capability, delivers a high reversible capacity of 102.6 mA h g−1 at 1C with a capacity retention of 94.2% after 100 cycles, and maintains a capacity of 78.2 mA h g−1 at 5C with a capacity retention of 78.3% after 300 cycles. This new strategy reduces the ratio of Mn3+/Mn4+, which alleviates the Jahn-Teller distortion effect and enhances the structural stability. Moreover, it expands the interlayer spacing that ensures the excellent rate performance of the cathode, as confirmed by the XPS, the Rietveld refinement of the XRD and the GITT measurement. This work demonstrates that the new composition cathode NLNBMMO-5% is promising for rechargeable sodium-ion batteries with a long cycling life and excellent rate performance.
研究领域:
材料科学
·
电化学
·
能源存储
✓ 已验证
产品关联
DOI
高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2017
·
IF 6.216
Jin-Yue Li,Hong-Yan Lü,Xiao-Hua Zhang,Yue-Ming Xing,Guang Wang,Hong-Yu Guan,Xing-Long Wu
Layered P2-type Na 0.53 MnO 2 nanorods is prepared by a simple solution reaction. When used as cathode material for sodium ion batteries, the P2-Na 0.53 MnO 2 delivers a high reversible capacity up to 135.7 mA h g −1 (theoretical capacity is 140 mA h g −1 ) at 0.1 C in the voltage range of 2–4.3 V vs. Na + /Na, corresponding to 0.51 mol of Na insertion/extraction. It presents good cycling performance and high rate capabilities. After 50 cycles, the capacity is just fading about 6.8% at the rate of 2 C. The significant behaviour of fast charging makes it be very attractive for practical application. The electrochemical impedance spectroscopy and galvanostatic intermittent titration technique are employed to investigate its sodium diffusion kinetics. The ex-situ X-ray diffraction technology is also used to study the intercalation/de-intercalation of sodium ions and the phase transition in the charging/discharging processes.
研究领域:
材料科学
·
电化学
✓ 已验证
DOI
高影响因子
JOURNAL OF ALLOYS AND COMPOUNDS
·
2023
·
IF 6.2
Xinyu Zhang,Hongxia Chen,Shuangwu Xu,Mengcheng Zhou,Rihuang Nie,Yutian Yang,Cheng Li,Hongming Zhou
P2-type layered transition metal oxides are considered one of the ideal cathode materials for sodium ion batteries because of its high working voltage and excellent theoretical specific capacity. P2-Na 0.67 Ni 0.33 Mn 0.67 O 2 electrodes deliver a theoretical specific capacity of 173 mAh g -1 , which is dependent on Ni 2+ /Ni 3+ /Ni 4+ charge compensation. High operating voltage leads to higher specific capacity and energy density , which are better adapted to practical development needs, but at the same time it causes the material to undergo a destructive P2-O2 phase transition, which greatly affect cycle stability and Na + diffusion kinetics. In this study, we propose Zn 2+ doping and spherical morphology modification strategy. The spherical morphology not only reduces the distance of Na + diffusion and improves the rate performance, but also the spherical structure can alleviate the volume change during Na + intercalation/extraction. Furthermore, the doping of Zn 2+ changes the valence distribution of Mn, suppressing the phase transition at high voltage and further improving the cycling stability. At a high cut-off voltage of 4.4 V, the cathode material with Zn 2+ doping and spherical shaped possesses an average operating voltage of up to 3.6 V and exhibits 90% capacity retention after 30 cycles (compared to only 56% for the pristine material). Above that, the rate performance is also greatly improved, with the modified material contributing an excellent specific capacity of 95 mAh g -1 , even at a high current density of 5 C (1 C = 170 mA g -1 ).
研究领域:
材料科学
·
电化学
✓ 已验证
产品关联
DOI
高影响因子
MATERIALS LETTERS
·
2019
·
IF 3.019
Miao Guan,Jiabin Chen,Xiaoping Zhang,Liu Yang,Binjue Wang,Shengkui Zhong
Yarn-ball-shaped P2-Na 2/3 Fe 1/2 Mn 1/2 O 2 nanofiber cathode material is synthesized by a magnetic-assisted electrospinning method. Based on the electrospinning method, an electromagnetic-field is performed to keep the nanofibers rotating to form the yarn-ball-like architecture. XRD result indicates that the sample is a pure P2-type Na 2/3 Fe 1/2 Mn 1/2 O 2 phase with good crystallization. SEM results show that the diameter of the balls is about 10–50 µm, and the balls are composed of nanofibers with a diameter of 200–400 nm. This special architecture is beneficial to increase the Na + diffusion speed and tap-density of nanofiber material. Electrochemical tests show that the sample has a high discharge specific capacity of 218.6 mAh g −1 at 0.1 C rate, and exhibits good rate capability and excellent cycling performance.
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
CHEMICAL ENGINEERING JOURNAL
·
2025
·
IF 13.2
Yu Duan,Jia-xuan He,Zi-han Ma,Shu-wen Chen,Ying-ying Huang,Shuo Bao,Jin-lin Lu
Sodium-ion batteries (SIBs) are gaining traction for large-scale energy storage due to sodium's abundance and cost efficiency, yet the structural instability and slow ion transport of P2-type cathodes remain critical challenges. This study employs a high-temperature solid-state approach to develop K/Cu co-doped cathodes, demonstrating that co-doping preserves the P2 phase while optimizing lattice parameters to expand interlayer spacing. The reduction in Mn 3+ content suppresses the Jahn-Teller effect and mitigates P2-O2 phase transitions, enhancing structural reversibility. The optimal K 0.05 Na 0.7 Ni 0.23 Mn 0.67 Cu 0.1 O 2 exhibits a high initial discharge capacity of 123.8 mAh·g −1 at 20 mA·g −1 and maintains 96.80 % capacity after 200 cycles at 200 mA·g −1 , outperforming single K-doped samples (89.83 % retention). Kinetic analyses reveal a sodium-ion diffusion coefficient of 1.06 × 10 −10 cm 2 ·s −1 , attributed to enlarged interlayers and reduced charge transfer resistance. In-situ XRD confirms minimal (002) peak shift (0.42°) during cycling, validating structural stability from K + -pinned interlayers. DFT calculations indicate that Cu doping induces spin-polarized half-metallic behavior, enhancing electron conductivity by increasing density of states near the Fermi level. This work presents a “dual-functional co-doping” strategy in which K + stabilizes interlayers and Cu 2+ optimizes the electronic structure, thereby simultaneously suppressing phase transitions and enhancing ion/electron transport. The proposed approach provides a scalable route for developing high-performance SIBs cathodes, which is crucial for advancing affordable and durable energy storage solutions.
研究领域:
材料科学
·
电化学
·
能源存储
·
固态化学
·
计算材料学
✓ 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）