ELECTROCHIMICA ACTA
·
2015
·
IF 4.504
Xinhe Yang,Zicheng Zuo,Haiyan Wang,Quanbin Chen,Hui Zhang,Zhenlei Huang,Borong Wu,Henghui Zhou
A one-step synthesis method is developed to prepare the Li[Ni 0.5 Co 0.2 Mn 0.3 ]O 2 (NCM 523) cathode with uniform tungsten-coating layer for lithium-ion battery . Such modified material shows similar properties with the bare NCM 523 in terms of the primary particles, secondary structure , and specific capacity. With W coating layer , the NCM 523 gives remarkable improvement in the long-term capacity retention in the half-cell testing, which is sharply inconsistent with the result from the full-battery tests, indicating a contradiction between the half-cell and full-battery tests in some case. After further investigations, such conflict between the half-cell and full-cell tests in evaluating the W-coating strategy is attributed to the dissolution of Li 2 WO 4 layer in the electrolyte, which probably destroys the solid electrolyte interface (SEI) on the graphite anode and irreversibly consumes the active lithium ions for renovating SEI in full-cell testing. These results will benefit researchers in the area of lithium-ion batteries to fully understand the differences between the half-cell and full-cell testing, and develop the effective strategies for cathode modifications.
研究领域:
电化学
·
材料科学
·
能源存储
·
电池技术
·
表面改性
·
固态离子学
✓ 已验证
DOI
高影响因子
JOURNAL OF MATERIALS SCIENCE
·
2017
·Vol. 52
·期 19
·11569-11579
·
IF 2.599
Lan Jin-Le,Ma Wenqiang,Deng Chengjie,Ren Guang-Kun,Lin Yuan-Hua,Yang Xiaoping
A series of K-doped Bi 1− x
K
x
CuSeO (0 ≤ x ≤ 0.10) compounds were prepared by combustion synthesis combined with spark plasma sintering method. Phase composition and microstructure analysis indicate almost single BiCuSeO phase in low doping level, while phase separation appears in heavy doping level. The thermoelectric properties of the Bi 1− x
K
x
CuSeO compounds have been measured in the temperature range of 323–823 K. The electrical conductivity is greatly enhanced by almost three times from 8.70 to 26.2 S/cm at 323 K by the substitution of Bi with K due to the large decrease of the activation energy. The overall thermal conductivity decreases significantly due to the strong point defect scattering by K doping and possibly enhanced interface scattering on the secondary phase. The maximum ZT reaches 0.6 at 823 K for the sample of x = 0.02, which is about 50% higher than that of the pristine sample. Our work offers a fast and more efficient approach for the fabrication of BiCuSeO-based materials.
研究领域:
材料科学
·
无机非金属材料
·
热电材料
·
固态化学
·
纳米复合材料
✓ 已验证
DOI
高影响因子
MATERIALS RESEARCH BULLETIN
·
2023
·
IF 5.4
Yu Zhang,Kai Li,Xuelian Zhou,Kaixuan Wang,Ze Wang,Sur Lig,Kefu Chao,Fengqi Zhao
Cr 3+ -doped near-infrared phosphors have recently attracted a wide attention. Here, NIR Ca 1- y Sr y Al 12- x Ga x O 19 :0.12Cr 3+ phosphors are obtained by a high-temperature solid-phase method. First, a series of CaAl 7.88 Ga 4 O 19 :0.12Cr 3+ samples is studied and shows that the crystal field strength can be tuned by cation substitutions, until achieving a sharp emission at 692 nm and a broad emission at 780 nm under a 400 nm excitation, and an internal quantum yield of 90.73%. A further substitution by an appropriate amount of Sr 2+ is suggested to be beneficial to increase the rigidity of the crystal structure by Debye temperature calculations. Experimentally, it is observed that Sr 2+ for Ca 2+ substitutions did not affect the luminescence wavelength and resulted in a significant increase of the thermal stability. When 0.7 Sr 2+ substitute Ca 2+ , the thermal stability at 450 K increased by 28% compared to the samples without Sr 2+ .
研究领域:
材料科学
·
无机化学
·
固体物理
·
光学材料
·
功能材料
✓ 已验证
DOI
高影响因子
SURFACE & COATINGS TECHNOLOGY
·
2019
·
IF 3.192
Lu Zhu,Yousen Zhu,Xuanru Ren,Ping Zhang,Jianghao Qiao,Peizhong Feng
MoSi 2 -MoB-ZrO 2 composite powders are one-step synthesized prepared by self-propagating high-temperature synthesis (SHS), which are further utilized to prepare the oxidation protective coatings by spark plasma sintering (SPS) method on molybdenum substrate. Microstructure and properties of the coatings were investigated and determined. Oxidation behavior of the coatings at high temperature was also studied. The results showed that the composite coating is dense and crack-free due to the addition of ZrO 2 , which is beneficial for the decrease of mismatch in coefficient of thermal expansion, and no void exists in the diffusion layer owing to the diffusion of Si, which is inhibited by adding MoB. Compared with the pure MoSi2 coating, the high hardness of the composite coating is enhanced by about 20% while the fracture toughness of the composite coating is improved by about 25%, which makes the occurrence of intergranular fracture , crack deflection and crack bridging. After oxidation at 1400 °C for 80 h, MoSi 2 coating failed while xMoSi 2 -MoB-3ZrO 2 (x = 3, 4, 5) composite coating still kept its protective effect. Only a little substrate is consumed during oxidation and improved oxidation resistance is gained by MoSi 2 -MoB-ZrO 2 composite coating. 3MoSi 2 -MoB-3ZrO 2 coating shows the relatively best oxidation resistance due to the formation of crack-free oxide film on the surface of the coating.
研究领域:
材料科学
·
表面工程
·
高温氧化
·
陶瓷涂层
·
粉末冶金
✓ 已验证
DOI
高影响因子
SOLID STATE IONICS
·
2019
·
IF 2.886
Fan Deng,Yongmin Wu,Weiping Tang,Shufeng Song,Zhaoyin Wen,Masashi Kotobuki,Li Lu,Jianyao Yao,Ning Hu,Janina Molenda
The use of garnet-type conductors as electrolytes for safe lithium solid-state batteries is impeded by the lack of critical processing strategy to stabilize and densify the cubic lithium garnets. The synthesis and processing of dense cubic lithium garnets are typically depending on solid state reaction as a result of unintentional Al contamination from the alumina crucibles at temperatures up to 1230 °C. High Al concentration is also believed to induce the sluggish migration of lithium ions . Here, we demonstrate an ultrathin, conformal γ-Al 2 O 3 surface coating on garnet solids by a hybrid microemulsion solid-state method for accomplishing rational and controllable synthesis and processing of dense cubic garnets with low Al concentration. The γ-Al 2 O 3 coating demonstrates fast-ion conducting Al-doped Li 6.75 La 3 Zr 1.75 Ta 0.25 O 12 phase with low Al concentration (~0.17 mol per formula unit), low tetragonal-to-cubic phase transformation temperature of 500 °C, and total conductivity of ~4.4 × 10 − 4 S cm − 1 . Specifically, the desired microstructures of the sintered pellets with uniform grains are revealed. As a proof-of-concept, we demonstrate that the nanoscale γ-Al 2 O 3 modification garnet conductor Li 6.75 La 3 Zr 1.75 Ta 0.25 O 12 is available to suppress lithium dendrites in symmetric Li/γ-Al 2 O 3 coating Li 6.75 La 3 Zr 1.75 Ta 0.25 O 12 /Li cells during lithium plating/stripping at room temperature, with current densities of 0.026 to 0.5 mA cm − 2 . The Li/γ-Al 2 O 3 coating Li 6.75 La 3 Zr 1.75 Ta 0.25 O 12 /LiNi 0.5 Co 0.2 Mn 0.3 O 2 cell delivered a high initial discharge capacity of ~164.2 mAh g − 1 , more importantly, an outstanding cycling performance with a capacity retention of 90.16% after 30 cycles at 0.1C and room temperature. This new synthesis route and the utilization of nanoscale γ-Al 2 O 3 surface modification could open up new avenue to lithium garnet conductors with reliable synthesis for all-solid-state lithium batteries application.
研究领域:
材料科学
·
电化学
·
固态离子学
·
能源存储
·
纳米材料
·
电池技术
✓ 已验证
DOI
高影响因子
JOURNAL OF ANALYTICAL AND APPLIED PYROLYSIS
·
2023
·
IF 6
Bingyang Li,Meiqian Chen
Massive spent ion exchange resins (SIERs) containing radionuclides are produced in nuclear power plants , which need to be treated reasonably. The migration mechanism of nuclides in SIER in both pyrolysis and gasification was evaluated from the chemical equilibrium analysis based on the Gibbs free energy minimization. The maximum volatility degrees of Co, Sr and Cs at 400–600 °C and 0.1 MPa were 0.01%, 0% and 0.1% in the pyrolysis . The maximum volatility degrees of Co, Sr and Cs were 0.015%, 0% and 100% at 600–1300 °C and 0.1 MPa in the gasification, and the steam concentration should be set mainly how to limit the volatilization of radionuclides . To reduce the volatility of nuclides as much as possible, the temperatures should be kept below 600 °C and 870 °C in the pyrolysis and gasification, respectively. The volatilization of Cs was greatly inhibited with lifting the pressure from 0.1 MPa to 1.5 MPa, which decreased from 0.103% to 0.007% in the pyrolysis (600 °C) and from 4.80% to 0.30% in the gasification (715 °C), respectively. Based on preventing the nuclides leakage, the negative pressure in the gasification should be controlled between 0.097 and 0.099 MPa. The volatilization of radionuclides was effectively weakened by adding a fixative, Zr(HPO 4 ) 2 ·H 2 O, since it could be helpful to reduce the gaseous cesium-based products in the pyrolysis and gasification. The volatility degree of Cs was close to 0 if Zr/Cs was great than or equal to 0.5. This study could provide basic data for the pyrolysis and gasification treatment of SIER.
研究领域:
核化学
·
环境工程
·
放射化学
·
废物处理
·
热力学分析
✓ 已验证
DOI
高影响因子
Journal of Materials Chemistry A
·
2021
·Vol. 9
·期 38
·22064-22071
·
IF 12.732
Wenda Zhang,Jie Feng,Fengqi Lu,Alberto J. Fernández-Carrión,Hui Fu,Xiaojun Kuang
Na-doped melilite-type silicate Sr2MgSi2O7 was reported to display high oxide ion conductivity. In this work, through multiple complementary techniques including X-ray diffraction, scanning electron microscopy, transmission electron microscopy, solid-state 29Si and 23Na nuclear magnetic resonance spectroscopy, and DFT calculations of defect formation energies, we found that it is hard to replace Sr with Na in Sr2MgSi2O7, and the Sr2−xNaxMgSi2O7−0.5x compositions formed mixed crystalline Sr2MgSi2O7 and Na-containing glassy phases. AC impedance spectroscopy measurements indicated that the ionic conduction in Sr2−xNaxMgSi2O7−0.5x could be from Na+ ions in the glassy phase, instead of the oxide ions.
研究领域:
材料科学
·
固体离子导体
·
无机非金属材料
·
能源材料
·
电化学
✓ 已验证
DOI
高影响因子
JOURNAL OF ALLOYS AND COMPOUNDS
·
2009
·
IF 1.51
Rongguan Lv,Jun Yang,Pengfei Gao,Yanna NuLi,Jiulin Wang
A mixture of nanoporous and nanofibrous silicon (NPNF-Si) is prepared by the mechanochemical reduction of SiCl 4 using Li 13 Si 4 as reducing agent in the presence of Super P carbon (SP) and the following thermal treatment and washing process. Morphologies and structures of the as-obtained composites are investigated using scanning electron microscopy (SEM), transmission electron microscopy (TEM) and X-ray diffraction (XRD). After carbon coating via pyrolysis of polyvinyl chloride (PVC), the resulting NPNF-Si/SP/C composite is evaluated for the use as anode material in lithium-ion battery. It exhibits the first discharge capacity of 746.6 mAh g −1 at current density of 0.2 mA mg −1 and capacity retention of 91.1% after 30 cycles. The good electrochemical performance arises from the particular Si nano-structure, which can alleviate the volume effect during lithium insertion and extraction.
研究领域:
材料科学
·
电化学
·
纳米科技
·
能源存储
·
锂离子电池
✓ 已验证
DOI
高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2019
·
IF 8.355
Kuan Wu,Gang Xu,Dengyu Pan,Minghong Wu
Combination of high-capacity and flexibility in electrode materials is crucial for flexible electronics. Recently, red phosphorus (P) has caused increasing focus as a hopeful storage material for lithium storage due to its super-high theoretical capacity and low cost. However, the low conductivity of red P and its large volume change during cycling process lead to reduced electrochemical activity. So far, no effective methods have been developed to construct flexible binder-free electrodes using red P as an active material for high-performance lithium-ion batteries (LIBs). Here, a novel hollow three‐dimensional (3D) internet structure as a flexible high-areal-capacity electrode material was fabricated by confining red P nanoparticles into compact MOF-derived carbon-based composite polyhedrons/carbon nanotube internets. The electrode manifests an excellent lithium storage performance for LIBs with a high discharge capacity of 4.78 mAh cm −2 (1920 mAh g −1 ) at 0.1 mA cm −2 and a good capacity retention of 79.2% at 1 mA cm −2 after 300 cycles (73% and 69% capacity retention at 5 and 10 mA cm −2 after 500 cycles, respectively). The novel flexible anode materials can provide excellent Li + storage performance for flexible electronics applications.
研究领域:
材料科学
·
电化学
·
纳米材料
·
能源存储
·
功能材料
·
先进电池技术
✓ 已验证
DOI
高影响因子
Journal of Environmental Chemical Engineering
·
2024
·Vol. 12
·期 5
·114091
·
IF 7.4
Xiaolong Dai,Tiangui Qi,Xiaobin Li,Zhihong Peng,Guihua Liu,Qiusheng Zhou,Yilin Wang,Leiting Shen
In recent years, lithium iron phosphate (LFP) batteries have been widely used in the electric vehicle industry. The recycling of spent LFP will be propitious to conserving resources and alleviating the environmental risks it poses. In this study, a selective extraction method for lithium from spent LFP was proposed using nitric acid . Lithium leached into the liquid phase, while P and Fe remained in the leaching residue. Under the conditions of 120°C, HNO 3 /Li molar ratio of 2, and time of 2 h, the leaching efficiency of lithium reached 99.5 %, with a selectivity reaching 82.1 %. Initially, LFP was decomposed to liberate Li, Fe, and P in the liquid phase. Subsequently, ferrous ions were oxidized to trivalent, high-valent iron ions re-precipitated as FePO 4 ·2 H 2 O. Thermodynamic calculations indicate that the temperature and pH value of the extraction system have significant influence on both the oxidation and reprecipitation steps. An imbalance of Fe/P ratio (<1) in the raw material hinders the selectivity of lithium extraction , and supplementing this portion of Fe can enhance the selectivity to over 90 %. Additionally, LiCO 3 and anhydrous FePO 4 were effectively regenerated from the leachate and residue. This study provides a novel approach for the recycling of spent LFP and probably contributes to the sustainability of the lithium ion battery industry.
研究领域:
环境科学
·
冶金工程
·
材料回收
·
可持续能源
·
化学工程
✓ 已验证
DOI
高影响因子
MATERIALS RESEARCH BULLETIN
·
2015
·
IF 2.288
J.L. Wang,E.H. Song,M. Wu,W.B. Dai,S. Ye,Q.Y. Zhang
Selectively enhanced green upconversion (UC) and near-infrared (NIR) downconversion (DC) emissions of Er 3+ by Yb 3+ -Mn 2+ dimer sensitizing have been demonstrated in Er 3+ /Yb 3+ /Mn 2+ tri-doped spinel MgGa 2 O 4 upon excitation of 980 nm laser diode (LD). By optimizing the doping rate of Mn 2+ , the intensity ratio of green to red UC emission intensities of Er 3+ (G/R) could be enhanced about 10 times. Meanwhile, the 1.5 μm NIR DC emission could also be increased about 3.6 times in this system. The DC and UC emission properties, UC mechanism, as well as the enhancing mechanism have been investigated and discussed in detail. A selectively enhancing mechanism based on Yb 3+ -Mn 2+ dimer sensitizing is proposed to explain the selectively enhancing phenomena. This work could inspire the design of novel UC materials for various applications, such as temperature sensors and optical transmission, etc.
研究领域:
光学材料
·
生物医学光子学
·
无机功能材料
·
分子影像
·
转化医学
✓ 已验证
DOI
高影响因子
Desalination and Water Treatment
·
2024
·
IF 1
Yan-zhen Shen,Xun-liang Wang,Yu-xiang Jia,Meng Wang
The endowment of perm-selectivity for specific ions will further extend the applications of heterogeneous membrane. In this work, a side-chain type weak cationic polyelectrolyte, PVDF-g-PVP, was synthesized for surface hydrophobilization of heterogeneous anion-exchange membrane (AEM) in order to impart perm-selectivity between specific anions with different Gibbs hydration energy. After microstructure observation and chemical composition analyses by SEM, AFM, EA and FTIR, the perm-selectivity between specific anions, electrical resistance, transport number, limiting current density, surface homogeneity, as well as salt permeability of the modified AEMs were investigated. Series of electrodialysis experiments in SO 4 2– /Cl – system indicated that a significant perm-selectivity was indeed achieved by the attachment of PVDF-g-PVP coating. In particular, it was worth noting that only a small loss of membrane conductivity was observed after the functionalization. This should be closely related to the micro-phase separation morphology of the coating layer which was induced by the polarity difference between the main chains and side chains of PVDF-g-PVP. Besides, the chronopotentiometric analyses indicated surface homogeneity of the heterogeneous AEM was significantly enhanced and then effectively ameliorated concentration polarization behaviors at the membrane-solution interface. Meanwhile, the perm-selectivity for co-ions was also improved and suppressed back diffusion behaviors of salt driven by concentration gradient. In brief, the modifying scheme proposed in this work can effectively improve comprehensive transport properties of conventional heterogeneous AEM.
研究领域:
膜科学与技术
·
高分子材料化学
·
分离科学
·
电化学工程
·
功能材料
✓ 已验证
DOI
高影响因子
危险品化学品经营许可证（带存储）