IONICS
·
2019
·Vol. 25
·期 10
·4567-4576
·
IF 2.289
Xu Chun-Sheng,Yu Hai-Tao,Guo Chen-Feng,Xie Ying,Ren Ning,Yi Ting-Feng,Zhang Guo-Xu
To improve the stability and performance of the cathode materials, an ionic conductor layer was coated successfully on the surface of Li 1.2 Mn 0.54 Ni 0.13 Co 0.13 O 2 (LMNC) microspheres. The structural analysis confirmed that LiV 3 O 8 coating did not change the basic structure of LMNC, and all obtained materials are solid solutions with a good-layered structure and a good crystallinity. The microscopy measurement showed that the thickness of the coating layer for the LV-3 sample is about 2.5 nm. This appropriate layer is helpful for improving the surface stability of LMNC and the diffusion of lithium, leading to an obvious enhancement of the electrochemical performance. Our result confirmed that the average discharge specific capacities for LV-3 sample at 0.1 C, 0.2 C, 0.5 C, 1 C, and 3 C are respectively 265.9, 219.1, 188.0, 156.3, and 121.5 mAh g −1 , which are much larger than the values of other samples. After 50 cycles at a 1 C rate, the capacity retentions for different samples are 60.7%, 74.0%, 87.6%, and 70.4%, indicating that LV-3 sample exhibits the best performance. Furthermore, EIS measurements showed that the diffusion coefficient for LV-3 sample is calculated to be 1.26 × 10 −15 cm 2 s −1 , which is also the largest value among all considered samples. Our experiments identified that coating an ionic conductive layer on the cathode material surface will significantly improve their rate capacity and cycling stability.
研究领域:
材料科学
·
电化学
·
能源存储
·
无机化学
·
固态离子学
✓ 已验证
DOI
高影响因子
JOURNAL OF POWER SOURCES
·
2017
·
IF 6.395
Haoxiang Yu,Minghe Luo,Hua Lan,Lei Yan,Shangshu Qian,Wuquan Ye,Miao Shui,Nengbing Long,Jie Shu
The preparation and characterization of Pb 1- x Ba x Li 2 Ti 6 O 14 ( x = 0, 1/4, 1/2, 3/4, 1) as anode materials for lithium ion batteries are investigated in this research. The structure, morphology and electrochemical properties are compared with each other by changing the Pb/Ba atomic ratio in Pb 1- x Ba x Li 2 Ti 6 O 14 . It can be observed that each sample shows the same orthorhombic structure with Cmca space group. Moreover, it can also be found that the working potential, conductivity, cycling and rate performances of as-received samples gradually change along with the evolution of x in Pb 1- x Ba x Li 2 Ti 6 O 14 ( x = 0, 1/4, 1/2, 3/4, 1). Electrochemical evaluation shows that the operating potential of the as-received sample gradually decreases with increasing x value in Pb 1- x Ba x Li 2 Ti 6 O 14 and its initial charge capacity increases reversely. Moreover, different Pb/Ba atomic ratio also brings different cycling stability for Pb 1- x Ba x Li 2 Ti 6 O 14 . Especially for Pb 3/4 Ba 1/4 Li 2 Ti 6 O 14 , it presents better electrochemical properties than other samples. After 120 cycles, the reversible capacity of Pb 3/4 Ba 1/4 Li 2 Ti 6 O 14 is maintained at 129.7 mAh g −1 with capacity retention of 88.3%. In addition, its electrochemical reversibility is also demonstrated by in-situ X-ray investigation.
研究领域:
材料科学
·
电化学
·
能源存储
·
无机化学
·
固态化学
✓ 已验证
DOI
高影响因子
ELECTROCHIMICA ACTA
·
2019
·
IF 5.383
Aijia Wei,Wen Li,Qian Chang,Xue Bai,Rui He,Lihui Zhang,Zhenfa Liu,Yanji Wang
Mg 2+ /F − co-doped LiNi 0.5 Mn 1.5 O 4 cathode material was synthesized by a facile one-step solid-state process. The effect of Mg 2+ /F − co-doping on grain morphology, phase structure, and electrochemical properties was studied by a series of characterizations. Scanning-electron-microscopy images show that Mg 2+ /F − co-doped LiNi 0.5 Mn 1.5 O 4 (denoted LNMO-MF) particles grow larger than pure LiNi 0.5 Mn 1.5 O 4 particles. X-ray diffraction, Raman spectra , Fourier transformation infrared spectroscopy , X-ray photoelectron spectroscopy, and cyclic-voltammetry tests indicate that all samples mainly display a Fd -3m space group and more Mn 3+ ions in the LNMO-MF sample after Mg 2+ /F − co-doping, which is conducive to increasing the cationic disorder degree and enhancing the electronic conductivity of electrode material. Results show that the LNMO-MF cathode material delivers an excellent rate performance with discharge capacities of 142, 144, 140 136, 132, 124, 115, and 100 mAh g −1 at 0.2, 0.5, 1, 2, 3, 5, 7, and 10C (1C = 140 mAh g −1 ), respectively. Remarkably, LNMO-MF also shows cycling stability with a capacity retention of 86.2% at 5C after 400 cycles, which is much higher than that of pure LiNi 0.5 Mn 1.5 O 4 (67.7%). The improvement of LNMO-MF's electrochemical properties could be ascribed to the Mg 2+ /F − co-doping, delivering a more stable structure, better crystallinity , the highest Li + diffusion coefficient , and the lowest charge-transfer resistance.
研究领域:
材料科学
·
电化学
·
无机非金属材料
·
能源存储
·
锂离子电池
·
固态化学
·
功能材料
✓ 已验证
DOI
高影响因子
POLYHEDRON
·
2016
·
IF 2.108
Tongguang Sun,Fei Liang,Xinyuan Zhang,Heng Tu,Zheshuai Lin,Guochun Zhang,Yicheng Wu
Single crystals of three new organic–inorganic hybrid compounds, tri[1-(diaminomethylene)uronium] hexachlorobismuthate ((C 2 H 7 N 4 S) 3 BiCl 6 ·H 2 O, HATU-BCH), bis[1-(diaminomethylene)uronium] pentabromobismuthate, ((C 2 H 7 N 4 S) 2 BiBr 5 , HATU-BB), and bis [3,5-diamino-1,2,4-thiadiazol-2-ium] pentaiodobismuthate ((C 2 H 5 N 4 S) 2 BiI 5 , OHATU-BI), have been successfully grown by slow evaporation method. Their structures were determined by single - crystal X-ray diffraction, in which all anion sublattice structures consist of hexahalobismuthates octahedra with different connection modes involving isolated, shared-corner, and shared-edge. The spectra characters were studied by Infrared and Raman spectra, which interpreted by calculation of the density functional theory (DFT) method and diffuse reflectance spectra. Thermal properties were characterized by thermal gravimetric analysis and differential scanning calorimetry.
研究领域:
材料化学
·
晶体工程
·
配位化学
·
光谱学
·
热分析
·
计算化学
✓ 已验证
DOI
高影响因子
PHYSICAL CHEMISTRY CHEMICAL PHYSICS
·
2016
·Vol. 18
·期 29
·19731-19737
·
IF 4.449
Yingna Cui,Jingmei Yin,Changping Li,Shenmin Li,Ailing Wang,Guang Yang,Yingping Jia
The compositions and structures of amine-based functionalized protic ionic liquids (PILs), namely N,N-dimethyl(cyanoethyl)ammonium propionate (DMCEAP) and N,N-dimethyl(hydroxyethyl)ammonium propionate (DMEOAP) have been investigated systematically by IR and 1H NMR spectroscopy and density functional theory (DFT) calculations. Analysis of the IR spectra suggests that both DMCEAP and DMEOAP are composed of neutral and ionized species in the liquid phase, the former one mainly existing in the state of precursor molecules, and the latter mainly as ion-pairs. The ratio of precursor molecules to ion-pairs in the liquid phase depends on the types of precursors, especially the functional groups of cations. 1H NMR spectra indicate that there is a dynamic equilibrium between the neutral and ionized species, probably due to the formation of some intermediates in the PILs. The DFT calculations have been carried out to reveal the conformation, and obtain the corresponding IR and 1H NMR spectra of the neutral and ionized species, so that the theoretical support to the experimental results can be provided. The present study will help understand the properties of PILs and provide guidance for further applications of PILs.
研究领域:
物理化学
·
离子液体化学
·
光谱学
·
理论化学
·
分析化学
·
材料化学
✓ 已验证
DOI
高影响因子
CERAMICS INTERNATIONAL
·
2021
·Vol. 48
·期 3
·3875-3883
·
IF 4.527
Qingliang Shan,Qian Ma,Changrong Chen,Qiankun Xu,Yudong Xue,Hao Xiong,Yewei Wang,Yuqian Zhou,Anze Shui
In this study, the effect of microcrcaks strengthening on damage evolution of Al 2 TiO 5 (AT) flexible ceramics was investigated by acoustic emission (AE). Results reveal that with increasing content of ZrO 2 , the strength of AT flexible ceramics improves gradually and the strain increases at first then decreases. When the content of ZrO 2 is 12% and 8%, the strength and strain at maximum stress are increased by 154.92% and 38.27%, respectively. In addition, thanks to the “strengthening effect” of ZrTiO 4 on grain boundary microcracks, the damage development thresholds ( σ min and σ onset ), elastic modulus and fracture toughness of AT flexible ceramics modified with ZrO 2 are significantly improved. Moreover, the visible transverse cracks and matrix shedding in ATZ-0 are the most, but the cumulative AE damage events in ATZ-8 and ATZ-4 are more than ATZ-0 at late stage, for which the fracture of ZrTiO 4 glass phase and crack branching induced by ZrTiO 4 should be responsible.
研究领域:
材料科学
·
陶瓷学
·
固态物理
·
力学性能
·
结构表征
·
断裂力学
✓ 已验证
DOI
高影响因子
危险品化学品经营许可证（带存储）