Progress in Natural Science-Materials International
·
2024
·
IF 4.8
Min Dong,Qingya Sun,Zhihua Wang,Zixin Rui,Zhe Zhang,He Zhu,Si Lan
Layered LiNi x Co y Mn z O 2 (NCM) cathode materials have emerged as the best choice for high-energy-density lithium-ion batteries for powering electric vehicles. Despite significant research efforts, the understanding of complex structural dynamics during lithium (de-) intercalation still remains a subject of debate, especially in scenarios where morphology and composition vary. In this study, we carried out in situ high-energy synchrotron X-ray diffraction experiments on commercial NCM523 cathode materials in both single crystal and polycrystalline forms to probe the structural changes during charging and discharging in detail. Our findings reveal that both single crystal and polycrystalline materials exhibit typical H1–H2–H3 phase transitions. However, in polycrystalline NCM532, a monoclinic intermediate phase emerges between the H1 and H2 phases. During this process, symmetry reduces from R -3 m to C 2/ m , which is attributed to a shear distortion along the ab plane. In contrast, for single crystal materials, the H1 phase directly transforms into the H2 phase without the monoclinic phase. The observed monoclinic distortion significantly impacts structural stability and material cycling performance. This study provides new insight into the structural dynamics in NCM532 cathode materials, particularly concerning morphology-dependent behaviors, which could deepen our understanding of the relationship between NCM material structures and their performance.
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 Today Communications
·
2024
·
IF 3.7
Teng Li,Ruizi Wang,Zikang Cai,Wenzhe Liu,Jiwei Song,Xixi Wu,Chunyan Cao,Liangjie Yuan
To date, LiCoO 2 has received extensive attention as a cathode material because of its unique characteristics. To satisfy the strong demand for high energy density , the cut-off voltage of LiCoO 2 is continuously increased. However, the structural instability of LiCoO 2 at a high cut-off voltage leads to capacity decay and many safety issues, which hinder further application of LiCoO 2 . Herein, YPO 4 is used to achieve a better electrochemical performance for LiCoO 2 at 4.55 V. In the synthesis process, YPO 4 is transformed into the Li 3 PO 4 and Y 2 O 3 phases, which are basically uniformly incorporated into the particle and form a composite with LiCoO 2 . Owing to the synergistic modification of Li 3 PO 4 and Y 2 O 3 phases, YPO 4 -modified LiCoO 2 materials show enhanced structural stability and excellent cycling performance. Particularly, 1.5% YPO 4 modified LiCoO 2 not only exhibits a reversible discharge capacity of 171.6 mAh g −1 over 500 cycles with 91.7% capacity retention, but also delivers a capacity of 144.5 mAh g −1 at 5 C (1 C = 274 mAh g −1 ). This work suggests that using rare-earth metal phosphates can be an effective strategy to improve the cycling performance of LiCoO 2 at 4.55 V.
研究领域:
材料科学
·
电化学
✓ 已验证
产品关联
DOI
高影响因子
IONICS
·
2021
·Vol. 27
·期 7
·2867-2876
·
IF 2.817
Yu Juan,Peng Jiaxin,Huang Wenlong,Wang Lejie,Wei Yinbo,Yang Naixing,Li Linbo
A Li 2 MoO 4 -coated LiNi 0.8 Co 0.1 Mn 0.1 O 2 cathode material was successfully synthesized by introducing Mo source during the lithium mixing process. The influence of Li 2 MoO 4 -coating on the structure, morphology, and electrochemical performance related to LiNi 0.8 Co 0.1 Mn 0.1 O 2 has been studied. The results of the cyclic voltammetry (CV) and differential voltage curve measurement show that the electrode polarization and irreversible capacity of the modified LiNi 0.8 Co 0.1 Mn 0.1 O 2 are smaller than the virgin material. Meanwhile, the capacity retention of LiNi 0.8 Co 0.1 Mn 0.1 O 2 increases from 64.6 to 90.59% after the 100th cycle at 1 C (1 C=200 mA g −1 ). Additionally, compared with the recycled materials, a thinner solid electrolyte interface (SEI) film was formed on the modified LiNi 0.8 Co 0.1 Mn 0.1 O 2 material. The improvement of the electrochemical performance for LiNi 0.8 Co 0.1 Mn 0.1 O 2 is mainly due to the existence of the Li 2 MoO 4 protective shell that improves the structural stability of the core material, avoids direct contact between the electrolyte and the active material, and suppresses the occurrence of side reaction.
研究领域:
材料科学
·
电化学
✓ 已验证
产品关联
DOI
高影响因子
APPLIED CLAY SCIENCE
·
2018
·
IF 3.641
Shun Wang,Peixin Du,Peng Yuan,Xuemin Zhong,Yaqi Liu,Dong Liu,Liangliang Deng
This work investigated changes in the chemical composition, structure and porosity of hollow spherical allophane under alkaline conditions, which are significant not only for understanding its fate in natural environment but also for its functional applications. Hollow spherical allophane with a silicon/aluminium (Si/Al) molar ratio of 0.77 was hydrothermally synthesised followed by treatment with dilute sodium hydroxide (NaOH) solutions with different concentrations (indicated by pH values). The allophane and its alkali-treated products were then characterized using a combination of techniques, such as Fourier-transform infrared spectroscopy, nuclear magnetic resonance and nitrogen physisorption analysis. Allophane showed a weak structural stability in alkaline conditions. At pH ≤ 11.0, the framework of allophane particles was almost intact; its polymerised silicates showed only slight dissolution. At a higher pH (> 11.0), desilication and dealumination enhanced, resulting in the destruction of the imogolite local structure (ImoLS) along the edges of defect pores and the formation of amorphous materials . Most of the defect pores increased in size, becoming accessible to nitrogen and the textural parameters of the micropores reached their maximum values at a pH of 12.5. However, the damage to some secondary pores and the collapse of some hollow spherules reduced total pore volume ( V total ). At a pH of 13.0, most of the hollow spherules were observed to have collapsed, resulting in remarkable decrease in the textural parameters. However, some unbroken and/or mildly broken allophane particles might remain, deduced from the relatively high BET specific surface area (SSA) and V total and the considerable proportion of micropores for Allo 13.0 . These results reveal the dissolution behaviour of allophane in alkaline conditions and the mechanism underlying this behaviour, providing essential insights into the mineral's potential applications.
研究领域:
土壤科学
·
矿物学
✓ 已验证
产品关联
DOI
高影响因子
Nanomaterials
·
2022
·Vol. 12
·期 5
·729
·
IF 5.719
Rui Zhang,Hengrui Qiu,Youxiang Zhang
The tungsten-doped (0.5 and 1.0 mol%) LiNi0.88Co0.09Al0.03O2(NCA) cathode materials are manufactured to systematically examine the stabilizing effect of W-doping. The 1.0 mol% W-doped LiNi0.88Co0.09Al0.03O2(W1.0-NCA) cathodes deliver 173.5 mAh g−1even after 100 cycles at 1 C, which is 95.2% of the initial capacity. While the capacity retention of NCA cathodes cycled in identical conditions is 86.3%. The optimal performances of the W1.0-NCA could be ascribed to the suppression of impendence increase and the decrease in anisotropic volume change, as well as preventing the collapse of structures during cycling. These findings demonstrate that the W-doping considerably enhances the electrochemical performance of NCA, which has potential applications in the development of Ni-rich layered cathode materials that can display high capacity with superior cycling stability.Keywords:tungsten doping;phase transition;structural stability;electrochemical performance;LiNi0.88Co0.09Al0.03O2
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
ACS Applied Materials & Interfaces
·
2022
·
IF 10.383
Yanmeng Cai,Yue Wang,Le Zhang,Rongli Fang,Jixiao Wang
Two-dimensional (2D) layered transition-metal carbides (MXenes) are attractive faradic materials for an efficient capacitive deionization (CDI) process owing to their high capacitance, excellent conductivity, and remarkable ion storage capacity. However, the easy restacking property and spontaneous oxidation in solution by the dissolved oxygen of MXenes greatly restrict their further application in the CDI domain. Herein, a three-dimensional (3D) heterostructure (MoS2@MXene) is rationally designed and constructed, integrating the collective advantages of MXene flakes and MoS2 nanosheets through the hydrothermal method. In such a design, the well-dispersed MXene flakes can effectively reduce the aggregation of MoS2 nanosheets, boost electrical conductivity, and provide efficient charge transfer paths. Furthermore, MoS2 nanosheets as the high-capacity interlayer spacer can prevent the self-restacking of MXene flakes and provide more active sites for ion intercalation. Meanwhile, the strong chemical interactions between MXene flakes and MoS2 nanosheets contribute to accelerating the charge transfer kinetics and enhancing structural stability. Consequently, the resulting MoS2@MXene heterostructure electrode possesses high specific capacitance (171.4 F g–1), fast charge transfer and permeation rate, abundant Na+ diffusion channels, and superior electrochemical stability. Moreover, the hybrid CDI cell (AC//MoS2@MXene) with AC as the anode and MoS2@MXene as the cathode delivers outstanding desalination capacity (35.6 mg g–1), rapid desalination rate (2.6 mg g–1 min–1), excellent charge efficiency (90.2%), and good cyclic stability (96% retention rate). Most importantly, the MoS2@MXene electrode can keep good structural integrity after the long-term repeated desalination process due to the effective shielding effect of the MoS2 layer to protect MXenes from being further oxidized. This work presents the flexible structural engineering to realize excellent ion transfer and storage process by constructing the 3D heterostructure.
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
ADVANCED FUNCTIONAL MATERIALS
·
2024
·
IF 18.5
Liu Gao,Fujie Li,Guangrong Zeng,Xin Jin,Zhenyou Li,Chao Wang
Elevating the charging cut-off voltage is an effective strategy to increase the energy density of LiCoO 2 . However, unstable interfacial structures and unfavorable phase transitions in bulk are inevitably triggered during deep de-lithiation at high voltage. Herein, an integrated surface-to-bulk Ti-modification strategy is applied to LiCoO 2 , enabling uniform Li 2 TiO 3 coating on the surface and gradient Ti-doping toward the structural bulk. The resultant Ti-modified LiCoO 2 (T-LCO) electrode can be stably cycled up to 4.6 V, providing a high-rate capability of 137 mAh g −1 at 5C and a long-life stability with 80.5% capacity retention after 400 cycles at 1C, far outperforming the unmodified LiCoO 2 electrode with only 50.7% capacity retention. In situ X-ray diffraction characterization and density functional theory calculation reveal that the synergistic modification of T-LCO enhances Li + diffusion, facilitates the construction of high-quality cathode/electrolyte interphase, reduces the phase transition from O3 to H1-3 and Co3d/O2p band overlap, and restrains layer-to-spinel phase distortion, thus improving structural stability at 4.6 V. This work presents a “two birds one step” strategy to enhance the cycling stability and achievable capacity of high-voltage LiCoO 2 for developing high energy density lithium-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
Journal of Physical Chemistry C
·
2017
·
IF 4.536
Chaonan Mu,Kaixiang Lei,Haixia Li,Fujun Li,Jun Chen
Tunnel-type Li3VO4 (LVO) has become of great interest as a promising anode material for lithium-ion batteries owing to its large capacity, low cost, and safe potentials. However, the poor conductivity of LVO limits its wide applications. Here, LVO was doped with 0.05 unit of Ti4+ in each formula (LTVO) via a solid-state synthetic method to increase its conductivity and structural stability. The partial replacement of V5+ with Ti4+ leads to formation of additional interstitial Li+ ions in the octahedrons between MO4 (M = Li, V) tetrahedrons and hence improves Li+ ion diffusion kinetics. The resultant LTVO electrode exhibits a high discharge/charge capacity of ∼376 mAh g–1 at 20 mA g–1. Good cycling stability over 500 cycles with small polarization is achieved at 1000 mA g–1. This makes it a promising anode for Li-ion batteries.
研究领域:
材料科学
·
电化学
✓ 已验证
DOI
高影响因子
Frontiers of Environmental Science & Engineering
·
2013
·Vol. 8
·期 2
·162-168
·
IF 0.886
Xie Jiangkun,Yan Naiqiang,Liu Fei,Qu Zan,Yang Shijian,Liu Ping
Porous ZIF-7 with the sodalite (SOD) cage structure (ZIF, Zeolitic imidazolate framework) were synthesized by the solvothermal method. Synthesized material was characterized by powder X-ray diffraction (PXRD), thermal gravity (TG), scanning electron microscopy (SEM) and N 2 adsorption analysis. ZIF-8 with the SOD structure and a little larger pore window was synthesized in a similar way and was characterized for comparisons. Thermal stability and structural stability of ZIF-7 were tested through PXRD analysis, and the capability of the material for CO 2 capture from simulated flue gas was investigated through physical adsorption method. The results showed that CO 2 adsorption capacity on ZIF-7 was about 48 mL·g −1 while the capacity on ZIF-8 was about 18 mg·g −1 (at 12°C and 0.98 P / P
0 relative pressure). Furthermore, the impact of flue gas components on adsorption capacity of ZIF-7 and the selectivity of CO 2 against N 2 on ZIF-7 was also investigated in this work.
研究领域:
材料科学
·
环境科学
✓ 已验证
DOI
高影响因子
APPLIED SURFACE SCIENCE
·
2021
·
IF 6.707
Yue Wu,Yangwen Chen,Shouqiang Huang,Guobiao Li,Shunping Sun,Yong Jiang,Guobin Liang,Songjian Zhao,Weiqiao Liu
The chloride (Cl − ) ions in wastewater are difficult to remove, since there is a lack of effective and recyclable chloride removal agents. In this study, the bismuth ferrites (BFO) are first explored as chloride removal agents, and their oxidation or precipitation effects on the Cl − removal are studied. In the BFO samples, the crystal phases of BiFeO 3 and Bi 2 FeO 4 have very limited contributions to the Cl − removal, while the enhanced removal ability is exhibited with the increase of Bi 25 FeO 40 . When the mass percentage of Bi 25 FeO 40 reaches 70%, high Cl − removal efficiencies of 80–90% are achieved, which even exceeds 95% for pure Bi 25 FeO 40 . The morphology and structure characterizations reveal that the excellent Cl − removal performance of Bi 25 FeO 40 is determined by its unstable chemical structure due to the sharing of Bi 5+ and Fe 3+ ions in the tetrahedral positions. The density of states and electron localization function of Bi 25 FeO 40 demonstrate that its Fe and O bonding is weaker than those of BiFeO 3 and Bi 2 FeO 4 , resulting in the easier breaking of the Fe 3+ /Bi 5+ -O bonds to release Bi 5+ ions, which have oxidation ability for the formation of OH and Cl radicals to enhance the Cl − removal efficiency.
研究领域:
环境科学
·
材料科学
✓ 已验证
DOI
高影响因子
RSC Advances
·
2016
·Vol. 6
·期 112
·111539-111548
·
IF 3.289
Hui Deng,Shi-Xi Zhao,Xia Wu,Lei Wei,Yu-Feng Deng,Ce-Wen Nan
The chief drawback of Li2MnSiO4 cathode materials is structural instability deriving from the transformation of [MnO4] tetrahedra to [MnO6] octahedra during oxidation from Mn(II) to Mn(III) and the Jahn–Teller effect especially from Mn(III) to Mn(IV). Based on the theory that Ni2+ could keep the [NiO4] ligand unchanged and stable during oxidation/reduction, [NiO4] tetrahedra may behave as a regional structural framework to support the total crystal lattice and alleviate structural distortion partially. In this paper we synthesize nano-Li2Mn1−xNixSiO4/C samples with a small amount of Ni as the dopant via a hydrothermal route. Firstly, we discuss the existential state of Ni through XPS spectra, and demonstrate that both Ni2+ and metallic Ni coexist, especially Ni2+ could improve structural stability. The influence of Ni doping on morphology, structural stability, and electrochemical performance is discussed through Raman spectroscopy and electrochemical tests below. It is confirmed that there exists an optimal Ni content under which the optimal performance is displayed. In our work, the optimum Ni content is 5.0%, and the maximal discharge capacity achieved is 235 mA h g−1 for the 5.0% Ni doped sample in the first cycle.
研究领域:
材料科学
·
电化学
✓ 已验证
DOI
高影响因子
JOURNAL OF NUCLEAR MATERIALS
·
2018
·
IF 2.447
Shuyang Li,Xiaoyong Yang,Jian Liu,Xiaofeng Zhao,Shahid Hussain,Yi Ding,Yong Yi,Tao Duan
Using Ce atom as the surrogate for tetravalence actinides, the structure stability, chemical bonding and solubility of Zr 1- x Ce x SiO 4 have been investigated by combing first principles calculations and static leach test (MCC-1) experimentally to understand the effect of actinides on stability of ZrSiO 4 . The structural analysis indicates that the high symmetry of [CeO 8 ] polyhedron could well maintain the structural stability of Zr 1- x Ce x SiO 4 . However, due to the longer and weaker Ce O bond than Zr O bond, LR Ce is slightly higher than LR Zr . Besides, the LR Zr and LR Ce are highest in acid leaching solution , followed in alkaline leaching solution and deionized water system. Worth noted, the negative solution energy of −22.254 eV indicates the pre-existing Zr vacancy is energetically favorite to accommodate actinides surrogate Ce impurities or quadrivalent actinides with slight structural deformation, showing the strong structural and chemical stabilities of ZrSiO 4 .
研究领域:
材料科学
·
核化学与放射化学
✓ 已验证
DOI
高影响因子
危险品化学品经营许可证（带存储）