共查询到20条相似文献,搜索用时 31 毫秒
1.
Dr. Shuang Li Dr. Zhenpeng Yao Prof. Jianming Zheng Dr. Maosen Fu Dr. Jiajie Cen Dr. Sooyeon Hwang Prof. Huile Jin Prof. Alexander Orlov Prof. Lin Gu Prof. Shun Wang Prof. Zhongwei Chen Prof. Dong Su 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2020,132(49):22276-22283
Ni-rich LiNi1−x−yMnxCoyO2 (NMC) layered compounds are the dominant cathode for lithium ion batteries. The role of crystallographic defects on structure evolution and performance degradation during electrochemical cycling is not yet fully understood. Here, we investigated the structural evolution of a Ni-rich NMC cathode in a solid-state cell by in situ transmission electron microscopy. Antiphase boundary (APB) and twin boundary (TB) separating layered phases played an important role on phase change. Upon Li depletion, the APB extended across the layered structure, while Li/transition metal (TM) ion mixing in the layered phases was detected to induce the rock-salt phase formation along the coherent TB. According to DFT calculations, Li/TM mixing and phase transition were aided by the low diffusion barriers of TM ions at planar defects. This work reveals the dynamical scenario of secondary phase evolution, helping unveil the origin of performance fading in Ni-rich NMC. 相似文献
2.
Suppressing the P2–O2 Phase Transition of Na0.67Mn0.67Ni0.33O2 by Magnesium Substitution for Improved Sodium‐Ion Batteries 下载免费PDF全文
Peng‐Fei Wang Ya You Dr. Ya‐Xia Yin Yue‐Sheng Wang Prof. Li‐Jun Wan Prof. Lin Gu Prof. Yu‐Guo Guo 《Angewandte Chemie (International ed. in English)》2016,55(26):7445-7449
Room‐temperature sodium‐ion batteries (SIBs) have shown great promise in grid‐scale energy storage, portable electronics, and electric vehicles because of the abundance of low‐cost sodium. Sodium‐based layered oxides with a P2‐type layered framework have been considered as one of the most promising cathode materials for SIBs. However, they suffer from the undesired P2–O2 phase transition, which leads to rapid capacity decay and limited reversible capacities. Herein, we show that this problem can be significantly mitigated by substituting some of the nickel ions with magnesium to obtain Na0.67Mn0.67Ni0.33?xMgxO2 (0≤x≤0.33). Both the reversible capacity and the capacity retention of the P2‐type cathode material were remarkably improved as the P2–O2 phase transition was thus suppressed during cycling. This strategy might also be applicable to the modulation of the physical and chemical properties of layered oxides and provides new insight into the rational design of high‐capacity and highly stable cathode materials for SIBs. 相似文献
3.
《中国化学快报》2023,34(6):107718
The Ni-rich LiNi0.8Co0.1Mn0.1O2 (NCM811) layered cathodes endow Li-ion batteries (LIBs) with high energy density. However, they usually suffer from limited ion-diffusion and structural instability during cycling. Although doping strategy can effectively alleviate these issues, the coupling effects of multi-element doping and the corresponding performance enhancement mechanism have been yet unclear. Here, we report a Zr/Ti dual-doped NCM811 cathode material (ZT-NCM811), in which Zr-ion is doped into both transition metal (TM) layers and lithium layers and Ti-ion is only distributed in TM layers. The dual-doping can effectively enhance crystal structure stability via inhibiting the lattice collapse along c-axis and decreasing the Li/Ni disorder. Meantime, the lattice oxygen escape is also greatly reduced due to the presence of stronger Zr-O and Ti-O bonds, further mitigating the crystal surface parasitic reactions with electrolyte. The resultant ZT-NCM811 exhibits high specific capacity of 124 mAh/g at even 10 C, much higher than undoped and single-doped NCM811, and a retention of 98.8% at 1 C after 100 cycles. The assembled ZT-NCM811/graphite full cell also delivers superior battery performances and durability. 相似文献
4.
Zhang Zhi-Ying 《中国化学》1986,4(1):7-19
On the basis of the experimental data reported in literature, the contributions of cation mass (m) and molar volume (V) to lattice heat capacity (C) were analyzed. The volumetric-mass formula, Cx=(l —f)·C1+f·C2+Cm·(mx — mx′), was presented for estimating the heat capacities of rare-earth compounds. In the formula C1 and C2 represent the lattice heat capacities of two reference substances respectively, f = Vx—V1/V2—V1 and Cm represents the lattice heat capacity variation with the variation 1 g of cation mass. The equation relating the Cm with temperatures was derived as follows: Cm = 0.084 e ?0.0074T ?0.27 e ?0.045T, and mx and mx′ (= (1 - f) m1+f m2) represent the practical and “assumed” cation masses of the substance in question respectively. 相似文献
5.
Yameng Fan Dr. Emilia Olsson Dr. Gemeng Liang Dr. Zhijie Wang Dr. Anita M. D'Angelo Dr. Bernt Johannessen Dr. Lars Thomsen Dr. Bruce Cowie Jingxi Li Fangli Zhang Dr. Yunlong Zhao Dr. Wei Kong Pang Dr. Qiong Cai Prof. Zaiping Guo 《Angewandte Chemie (International ed. in English)》2023,62(5):e202213806
The application of Li-rich layered oxides is hindered by their dramatic capacity and voltage decay on cycling. This work comprehensively studies the mechanistic behaviour of cobalt-free Li1.2Ni0.2Mn0.6O2 and demonstrates the positive impact of two-phase Ru doping. A mechanistic transition from the monoclinic to the hexagonal behaviour is found for the structural evolution of Li1.2Ni0.2Mn0.6O2, and the improvement mechanism of Ru doping is understood using the combination of in operando and post-mortem synchrotron analyses. The two-phase Ru doping improves the structural reversibility in the first cycle and restrains structural degradation during cycling by stabilizing oxygen (O2−) redox and reducing Mn reduction, thus enabling high structural stability, an extraordinarily stable voltage (decay rate <0.45 mV per cycle), and a high capacity-retention rate during long-term cycling. The understanding of the structure-function relationship of Li1.2Ni0.2Mn0.6O2 sheds light on the selective doping strategy and rational materials design for better-performance Li-rich layered oxides. 相似文献
6.
M. Akhilash P. S. Salini Bibin John S. Sujatha T. D. Mercy 《Chemical record (New York, N.Y.)》2023,23(11):e202300132
Nickel-rich (Ni-rich) layered oxides are considered as the most promising cathode candidates for lithium-ion cells owing to their high theoretical specific capacity. However, the higher nickel content endows structural deformation through unwanted phase transitions and parasitic side reactions that lead to capacity fading upon prolonged cycling. Hence, a deep understanding of the chemistry and structural behaviour is essential for developing Ni-rich Lithium Nickel Cobalt Manganese oxide (NCM) cathode-based high-energy batteries. The present review focuses on the different challenges associated with Ni-rich NCM materials and surface modification as a strategy to solve the issues associated with NCM materials, assessment of several coating materials, and the recent developments in the surface modification of Ni-rich NCMs, with an in-depth discussion on the impact of coating on the degradation mechanism. 相似文献
7.
Dr. Biyu Jin Zehao Cui Prof. Arumugam Manthiram 《Angewandte Chemie (International ed. in English)》2023,62(15):e202301241
The practical viability of high-nickel layered oxide cathodes is compromised by the interphasial and structural degradations. Herein, we demonstrate that by applying an in situ interweaved binder, the cycling stability of high-nickel cathodes can be significantly improved. Specifically, the results show that the resilient binder network immobilizes the transition-metal ions, suppresses electrolyte oxidative decomposition, and mitigates cathode particles pulverization, thus resulting in suppressed cathode-to-anode chemical crossover and ameliorated chemistry and architecture of electrode-electrolyte interphases. Pouch full cells with high-mass-loading LiNi0.8Mn0.1Co0.1O2 cathodes achieve 0.02 % capacity decay per cycle at 1 C rate over 1 000 deep cycles at 4.4 V (vs. graphite). This work demonstrates a rational structural and compositional design strategy of polymer binders to mitigate the structural and interphasial degradations of high-Ni cathodes in lithium-ion batteries. 相似文献
8.
Jibin Zhang Yanjun Zhong Xiaxing Shi Zhuo Zheng Weibo Hua Yanxiao Chen Wenyuan Liu Benhe Zhong 《中国化学》2015,33(11):1303-1309
Porous structure Li[Ni1/3Co1/3Mn1/3]O2 has been synthesized via a facile carbonate co‐precipitation method using Li2CO3 as template and lithium‐source. The physical and electrochemical properties of the materials were examined by many characterizations including TGA, XRD, SEM, EDS, TEM, BET, CV, EIS and galvanostatic charge‐discharge cycling. The results indicate that the as‐synthesized materials by this novel method own a well‐ordered layered structure α‐NaFeO2 [space group: R‐3m(166)], porous morphology, and an average primary particle size of about 150 nm. The porous material exhibits larger specific surface area and delivers a high initial capacity of 169.9 mAh·g?1 at 0.1 C (1 C=180 mA·g?1) between 2.7 and 4.3 V, and 126.4, 115.7 mAh·g?1 are still respectively reached at high rate of 10 C and 20 C. After 100 charge‐discharge cycles at 1 C, the capacity retention is 93.3%, indicating the excellent cycling stability. 相似文献
9.
Hyesu Lee Eunmi Jo Dr. Kyung Yoon Chung Prof. Dongjin Byun Dr. Seung Min Kim Dr. Wonyoung Chang 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2020,132(6):2406-2412
The structural stability of cathode materials during electrochemical reactions, in particular, under high-rate discharge, is pertinent to the design and development of new electrode materials. This study investigates the structural inhomogeneity that develops within a single LiNi0.835Co0.15Al0.015O2 (NCA83) particle during a fast discharging process under different cutoff voltages. Some of the NCA83 particles discharged from a high cutoff voltage (4.8 V) developed surface areas in which the layered structure was recovered, although the interiors retained the degraded spinel structure. These micro- and nano-scale structural inversions from high cutoff voltage seem highly correlated with structural evolutions in the initial charged state, and may ultimately degrade the cycling stability. This study advances understanding of the structural inhomogeneity within primary particles during various electrochemical processes and may facilitate the development of new Ni-rich cathode materials. 相似文献
10.
Soft Phonon Modes Leading to Ultralow Thermal Conductivity and High Thermoelectric Performance in AgCuTe 下载免费PDF全文
Subhajit Roychowdhury Manoj K. Jana Jaysree Pan Satya N. Guin Prof. Dirtha Sanyal Prof. Umesh V. Waghmare Prof. Kanishka Biswas 《Angewandte Chemie (International ed. in English)》2018,57(15):4043-4047
Crystalline solids with intrinsically low lattice thermal conductivity (κL) are crucial to realizing high‐performance thermoelectric (TE) materials. Herein, we show an ultralow κL of 0.35 Wm?1 K?1 in AgCuTe, which has a remarkable TE figure‐of‐merit, zT of 1.6 at 670 K when alloyed with 10 mol % Se. First‐principles DFT calculation reveals several soft phonon modes in its room‐temperature hexagonal phase, which are also evident from low‐temperature heat‐capacity measurement. These phonon modes, dominated by Ag vibrations, soften further with temperature giving a dynamic cation disorder and driving the superionic transition. Intrinsic factors cause an ultralow κL in the room‐temperature hexagonal phase, while the dynamic disorder of Ag/Cu cations leads to reduced phonon frequencies and mean free paths in the high‐temperature rocksalt phase. Despite the cation disorder at elevated temperatures, the crystalline conduits of the rigid anion sublattice give a high power factor. 相似文献
11.
Dr. Wengao Zhao Dr. Kuan Wang Prof. Xinming Fan Fucheng Ren Xieyu Xu Dr. Yangyang Liu Dr. Shizhao Xiong Dr. Xiangsi Liu Zhengfeng Zhang Mayan Si Ruizhuo Zhang Dr. Wessel van den Bergh Prof. Pengfei Yan Dr. Corsin Battaglia Dr. Torsten Brezesinski Prof. Yong Yang 《Angewandte Chemie (International ed. in English)》2023,62(32):e202305281
Single-crystal LiNixCoyMnzO2 (SC-NCM, x+y+z=1) cathodes are renowned for their high structural stability and reduced accumulation of adverse side products during long-term cycling. While advances have been made using SC-NCM cathode materials, careful studies of cathode degradation mechanisms are scarce. Herein, we employed quasi single-crystalline LiNi0.65Co0.15Mn0.20O2 (SC-NCM65) to test the relationship between cycling performance and material degradation for different charge cutoff potentials. The Li/SC-NCM65 cells showed >77 % capacity retention below 4.6 V vs. Li+/Li after 400 cycles and revealed a significant decay to 56 % for 4.7 V cutoff. We demonstrate that the SC-NCM65 degradation is due to accumulation of rock-salt (NiO) species at the particle surface rather than intragranular cracking or side reactions with the electrolyte. The NiO-type layer formation is also responsible for the strongly increased impedance and transition-metal dissolution. Notably, the capacity loss is found to have a linear relationship with the thickness of the rock-salt surface layer. Density functional theory and COMSOL Multiphysics modeling analysis further indicate that the charge-transfer kinetics is decisive, as the lower lithium diffusivity of the NiO phase hinders charge transport from the surface to the bulk. 相似文献
12.
Yongjiang Sun Changhong Wang Wenjin Huang Genfu Zhao Lingyan Duan Qing Liu Shimin Wang Adam Fraser Hong Guo Xueliang Sun 《Angewandte Chemie (International ed. in English)》2023,62(20):e202300962
Nickel-rich (Ni≥90 %) layered cathodes are critical materials for achieving higher-energy-density and lower-cost next-generation Li-ion batteries (LIBs). However, their bulk and interface structural instabilities significantly impair their electrochemical performance, thus hindering their widespread adoption in commercial LIBs. Exploiting Ti and Mo diffusion chemistry, we report one-step calcination to synthesize bulk-to-surface modified LiNi0.9Co0.09Mo0.01O2 (NCMo90) featuring a 5 nm Li2TiO3 coating on the surface, a Mo-rich Li+/Ni2+ superlattice at the sub-surface, and Ti-doping in the bulk. Such a multi-functional structure effectively maintains its structural integrity upon cycling. As a result, such NCMo90 exhibits a high initial capacity of 221 mAh g−1 at 0.1 C, excellent rate performance (184 mAh g−1 at 5 C), and high capacity retention of 94.0 % after 500 cycles. This work opens a new avenue to developing industry-applicable Ni-rich cathodes for next-generation LIBs. 相似文献
13.
Preparation and Characterization of TiO2-pillared Layered HNb3O8 总被引:1,自引:0,他引:1
IntroductionThelayeredcompoundssuchassmectiteclays,me-tallicphosphatesandtransitionmetaloxidespillaredwithinorganicoxideshavebeenattractingmoreandmoreattentionfrombothacademicandindustrialfieldsduetotheirpotentialapplicationsinadsorption,separa-tion,conductionandparticularlycatalysis.1-7NiobatessuchasKNb3O8andK4Nb6O17,andthecorrespondingprotonicoxides,HNb3O8andH4Nb6O17,aremembersofthefamilyoflayeredtransitionmetaloxidesbasedonoctahedralframeworkstructure,inwhichK+orH+liesbetweenlayersbuil… 相似文献
14.
SUN Junli JIAO Lifang LIU Li WEI Xin YANG Lin LIU Sichen YUAN Huatang WANG Yongmei 《中国化学》2009,27(5):863-867
溶胶凝胶法合成了层状的LiTiyV3-0.8yO8(y=0, 0.04, 0.06, 0.08)正极材料,这些材料因为掺杂Ti量的不同,而具有了不同的形貌特征(形状,粒径,比表面积)以及电化学性质(首次充放电容量, 循环容量等)。XRD,SEM, CV,及充放电测试对该正极材料的结构和电化学性能进行了表征,结果表明当y=0.04时,该正极材料拥有最高的首次放电容量(348.9mAhg-1)和最好的容量循环性能。 相似文献
15.
We report a method to eliminate the irreversible capacity of 0.4Li_2MnO_3·0.6LiNi_(0.5)Mn_(0.5)O_2(Li_(1.17)Ni_(0.25)Mn_(0.583)O_2) by decreasing lithium content to yield integrated layered-spinel structures.XRD patterns,High-resolution TEM image and electrochemical cycling of the materials in lithium cells revealed features consistent with the presence of spinel phase within the materials.When discharged to about 2.8 V,the spinel phase of LiM_2O_4(M=Ni,Mn) can transform to rock-salt phase of Li_2M_2O_4(M=Ni,Mn) during which the tetravalent manganese ions are reduced to an oxidation state of 3.0.So the spinel phase can act as a host to insert back the extracted lithium ions(from the layered matrix) that could not embed back into the layered lattice to eliminate the irreversible capacity loss and increase the discharge capacity.Their electrochemical properties at room temperature showed a high capacity(about 275 mAh g~(-1) at 0.1 C) and exhibited good cycling performance. 相似文献
16.
: The air-stable phosphide, ZnCu2P8, was synthesized from its elements in gram amounts. It crystallizes in the Cu2.5In0.5P8 structure type [C2/c, Z = 4, a = 1110.8(2) pm, b = 964.7(2) pm, c = 752.7(1) pm, β = 110.027(3)°], and is the first ternary phosphide in the system Zn/Cu/P. Its crystal structure consists of two-dimensional, layered polyphosphide-anions, separated by tetrahedrally-coordinated cations. 135 symmetry independent configurations, each with a different and specific Zn2+ and Cu+ arrangement, where explored with density functional methods. Whereby, each of the 135 cation ordering pattern has a diverse bandgap, and the total energies vary in the range of 1 eV. As several configurations with low energy are close in energy, an intrinsic disorder is discussed as origin of the promising low lattice thermal conductivity, observed. 相似文献
17.
Justin Mark Michael P. Hanrahan Dr. Katherine E. Woo Shannon Lee Prof. Dr. Aaron J. Rossini Prof. Dr. Kirill Kovnir 《Chemistry (Weinheim an der Bergstrasse, Germany)》2019,25(25):6392-6401
Lithiation of van der Waals tetrel-arsenides, GeAs and SiAs, has been investigated. Electrochemical lithiation demonstrated large initial capacities of over 950 mAh g−1 accompanied by rapid fading over successive cycling in the voltage range 0.01–2 V. Limiting the voltage range to 0.5–2 V achieved more stable cycling, which was attributed to the intercalation process with lower capacities. Ex situ powder X-ray diffraction confirmed complete amorphization of the samples after lithiation, as well as recrystallization of the binary tetrel-arsenide phases after full delithiation in the voltage range 0.5–2 V. Solid-state synthetic methods produce layered phases, in which Si-As or Ge-As layers are separated by Li cations. The first layered compounds in the corresponding ternary systems were discovered, Li0.9Ge2.9As3.1 and Li3Si7As8, which crystallize in the Pbam (No. 55) and P2/m (No. 10) space groups, respectively. Semiconducting layered GeAs and SiAs accommodate the extra charge from Li cations through structural rearrangement in the Si-As or Ge-As layers and eventually by replacement of the tetrel dumbbells with sets of Li atoms. Ge and Si monoarsenides demonstrated high structural flexibility and a mild ability for reversible lithiation. 相似文献
18.
Shangyun Ye Yongyao Xia Pingwei Zhang Zhiyu Qiao 《Journal of Solid State Electrochemistry》2007,11(6):805-810
A series of the mixed transition metal compounds, Li[(Ni1/3Co1/3Mn1/3)1–x-y
Al
x
B
y
]O2-z
F
z
(x = 0, 0.02, y = 0, 0.02, z = 0, 0.02), were synthesized via coprecipitation followed by a high-temperature heat-treatment. XRD patterns revealed that
this material has a typical α-NaFeO2 type layered structure with R3-
m space group. Rietveld refinement explained that cation mixing within the Li(Ni1/3Co1/3Mn1/3)O2 could be absolutely diminished by Al-doping. Al, B and F doped compounds showed both improved physical and electrochemical
properties, high tap-density, and delivered a reversible capacity of 190 mAh/g with excellent capacity retention even when
the electrodes were cycled between 3.0 and 4.7 V. 相似文献
19.
Synthesis Pb1‐xBi4+xTi4‐xMnxO15 compounds (0 ≤ × ≤ 1) were carried out by molten salts method using eutectic mixture of Na2SO4/K2SO4 salts (1:1 molar ratio) as the flux. The samples were characterized by X‐ray powder diffraction and refined by Le Bail method using Rietica program. The refinement results revealed that the compounds with the composition 0 ≤ x ≤ 0.6 formed Aurivillius phase with the space group A21am while the other composition (x ≥ 0.8) showed another phase beside A21am. The ratio b/a of the lattices constants for all the samples are larger than 1 indicating the direction of the orthorhombic along the b axis of their cells. The lattice parameters and volume of the unit cells decrease as the Mn content increasing from x = 0 to 0.6, for x ≥ 0.8 a second phase were observed. The morphologies of Pb1‐xBi4+xTi4‐xMnxO15 samples were observed by SEM and show plate‐like aggregate crystals, typical of layered compounds belonging to the Aurivillius phase. 相似文献
20.
Xiangsi Liu Wenhua Zuo Bizhu Zheng Yuxuan Xiang Ke Zhou Zhumei Xiao Peizhao Shan Jingwen Shi Qi Li Guiming Zhong Riqiang Fu Yong Yang 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2019,131(50):18254-18263
Sodium layered P2‐stacking Na0.67MnO2 materials have shown great promise for sodium‐ion batteries. However, the undesired Jahn–Teller effect of the Mn4+/Mn3+ redox couple and multiple biphasic structural transitions during charge/discharge of the materials lead to anisotropic structure expansion and rapid capacity decay. Herein, by introducing abundant Al into the transition‐metal layers to decrease the number of Mn3+, we obtain the low cost pure P2‐type Na0.67AlxMn1?xO2 (x=0.05, 0.1 and 0.2) materials with high structural stability and promising performance. The Al‐doping effect on the long/short range structural evolutions and electrochemical performances is further investigated by combining in situ synchrotron XRD and solid‐state NMR techniques. Our results reveal that Al‐doping alleviates the phase transformations thus giving rise to better cycling life, and leads to a larger spacing of Na+ layer thus producing a remarkable rate capability of 96 mAh g‐1 at 1200 mA g‐1. 相似文献