scholarly journals Improved Electrochemical Performance of 0.5Li2MnO3·0.5LiNi0.5Mn0.5O2 Cathode Materials for Lithium Ion Batteries Synthesized by Ionic-Liquid-Assisted Hydrothermal Method

2020 ◽  
Vol 8 ◽  
Author(s):  
Yanhong Xiang ◽  
Youliang Jiang ◽  
Saiqiu Liu ◽  
Jianhua Wu ◽  
Zhixiong Liu ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Ionic Liquid ◽  
Electrochemical Performance ◽  
Hydrothermal Method ◽  
Cathode Materials ◽  
Electrochemical Impedance ◽  
Rate Capability ◽  
Lithium Ion ◽  
Charge Transfer Resistance ◽  
Transfer Resistance

Well-dispersed Li-rich Mn-based 0.5Li2MnO3·0.5LiNi0.5Mn0.5O2 nanoparticles with diameter ranging from 50 to 100 nm are synthesized by a hydrothermal method in the presence of N-hexyl pyridinium tetrafluoroborate ionic liquid ([HPy][BF4]). The microstructures and electrochemical performance of the prepared cathode materials are characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and electrochemical measurements. The XRD results show that the sample prepared by ionic-liquid-assisted hydrothermal method exhibits a typical Li-rich Mn-based pure phase and lower cation mixing. SEM and TEM images indicate that the extent of particle agglomeration of the ionic-liquid-assisted sample is lower compared to the traditional hydrothermal sample. Electrochemical test results indicate that the materials synthesized by ionic-liquid-assisted hydrothermal method exhibit better rate capability and cyclability. Besides, electrochemical impedance spectroscopy (EIS) results suggest that the charge transfer resistance of 0.5Li2MnO3· 0.5LiNi0.5Mn0.5O2 synthesized by ionic-liquid-assisted hydrothermal method is much lower, which enhances the reaction kinetics.

Concentration-Controlled and Phytic Acid-Assisted Synthesis of Self-Assembled LiFePO4 as Cathode Materials for Lithium-Ion Battery

NANO ◽  
2020 ◽  
Vol 15 (01) ◽  
pp. 2050003
Author(s):  
Yin Li ◽  
Keyu Zhang ◽  
Zhengjie Chen ◽  
Yunke Wang ◽  
Li Wang ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Diffusion Coefficient ◽  
Electrochemical Performance ◽  
Phytic Acid ◽  
Cathode Materials ◽  
Electrochemical Impedance ◽  
Lithium Ion ◽  
Precursor Concentration ◽  
Phosphorus Source ◽  
Self Assembled

The olivine LiFePO4 with various morphologies and different growth lattice planes was prepared by a controllable hydrothermal method with changing precursor concentration and using phytic acid as phosphorus source. The microstructure, crystal orientation and electrochemical performance of the prepared samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), high-resolution transmission electron microscopy (HR-TEM) and charge–discharge tests. The results show that the morphologies of all samples change from spindle-like to hierarchical plate-like and then to long plate-like shape, and the main exposed facets transform from (100) to (001). This indicates that the precursor concentration and phytic acid play important roles in exposing facets and controlling the morphology of LiFePO4. In order to illustrate these phenomena, a reasonable assembly process is provided and the formation is explained. Li ion diffusion coefficient along [100] and [001] directions was calculated by using electrochemical impedance spectroscopy (EIS). The results show that the diffusion coefficient of (100) facet is higher than that of (001) facet, indicating a good electrochemical performance for (100) facet. In addition, the capacity test is carried out, which also confirms the above results. With the precursor concentration of 0.5[Formula: see text]M, the obtained LiFePO4 with self-assembled hierarchical structure, smaller size and (100) facet shows the best electrochemical performance: 162.1[Formula: see text]mAh/g at 0.1[Formula: see text]C and 112.4[Formula: see text]mAh/g at 10[Formula: see text]C. Using phytic acid as phosphorus source and controlling precursor concentration to prepare high performance LiFePO4 open up a new prospect for the production of cathode materials for lithium ion batteries.

Preparation and Electrochemical Performance of Mg2 + Doped Li4Ti5O12 Anode Materials for Lithium-Ion Batteries

2019 ◽  
Vol 960 ◽  
pp. 238-243
Author(s):  
Ming Wang ◽  
Xue Ming Zhang ◽  
Ying Bo Wang ◽  
Li Li Cheng ◽  
Xue Lei Wang ◽  
...  
Keyword(s):  
Electrochemical Performance ◽  
Electrochemical Impedance ◽  
Solid Phase ◽  
Retention Rate ◽  
Specific Capacity ◽  
Lithium Ion ◽  
Charge Transfer Resistance ◽  
Solid Phase Reaction ◽  
Phase Reaction ◽  
Transfer Resistance

Spinel Li4Ti5O12 (LTO) doped with Mg2+ was synthesized by solid-phase reaction method. The Mg2+ doping quantity was 3%, 6%, 9%, and 12%, respectively. The structure and electrochemical performance of the prepared LTO composites were investigated by X-ray diffraction (XRD), Scanning Electron Microscopy (SEM), Electrochemical Impedance Spectroscopy (EIS), and galvanostatic charge-discharge tests. It was found that the doped Mg ion did not change the structure of Li4Ti5O12, and it was evenly distributed around Li4Ti5O12. When Mg2+ doping quantity increased from 3% to 12%, the internal resistance and charge transfer resistance of the composite both decreased. The first discharge specific capacity of 6%-Mg2+ doped LTO composite was 168 mAh/g, which was close to the theoretical capacity of pure lithium titanate (175 mAh/g), and the capacity retention rate was 98% after 100 cycles.

Improved electrochemical performance of LiNi0.8Co0.15Al0.05O2/LiMn1∕3Ni1∕3Co1∕3O2 with core-shell structure synthesized by a coprecipitation and spray pyrolysis process

2018 ◽  
Vol 11 (04) ◽  
pp. 1850083 ◽  
Author(s):  
Hongyong Ouyang ◽  
Xinhai Li ◽  
Zhixing Wang ◽  
Huajun Guo ◽  
Wenjie Peng ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Electrochemical Performance ◽  
Spray Pyrolysis ◽  
Electrochemical Impedance ◽  
Rate Capability ◽  
Lithium Ion ◽  
Cycling Performance ◽  
Core Shell ◽  
Pyrolysis Process ◽  
Spray Pyrolysis Process

Core-shell composite material LiNi[Formula: see text]Co[Formula: see text]Al[Formula: see text]O2/LiMn[Formula: see text]Ni[Formula: see text]Co[Formula: see text]O2 (NCA/NCM) was synthesized via a coprecipitation and spray pyrolysis process. The properties of pristine LiNi[Formula: see text]Co[Formula: see text]Al[Formula: see text]O2 (NCA) and Core-shell NCA/NCM were investigated by scanning electron microscopy, transmission electron microscopy, Galvanostatic cell cycling and electrochemical impedance spectroscopy. Results showed that the Core-shell NCA/NCM exhibited enhanced rate capability and cycling performance than the pristine NCA. The improved electrochemical performance is due to the fact that the NCM layer can stabilize the crystal structure of materials and suppress the deterioration of lithium ion diffusing ability during electrode process.

Synthesis of LiMn0.7Fe0.3PO4/C Composite Cathode Materials for Lithium-Ion Batteries

2013 ◽  
Vol 634-638 ◽  
pp. 2617-2620
Author(s):  
Na Chi ◽  
Jian Gang Li ◽  
Lei Wang ◽  
Jie Si Fu
Keyword(s):  
Electrochemical Performance ◽  
Electrochemical Impedance ◽  
Lithium Ion ◽  
Solid State Reaction Method ◽  
Composite Cathode ◽  
Charge Transfer Resistance ◽  
Electrochemical Impedance Spectra ◽  
Transfer Resistance ◽  
Cation Order ◽  
Increasing Temperature

LiMn0.7Fe0.3PO4/C composite cathode material was prepared by using a solid state reaction method. The effects of annealing temperatures on the structural and electrochemical performance of LiMn0.7Fe0.3PO4/C were investigated by using X-ray diffraction (XRD), scanning electron microscope (SEM), charge–discharge tests and electrochemical impedance spectra (EIS). The results showed that all of samples have pure ordered olivine phase with orthorhombic Pnma structure. The electrochemical performance of LiMn0.7Fe0.3PO4/C can be improved remarkably with increasing temperature from 550oC to 650 oC due to increased crystallization, cation-order and decreased charge transfer resistance. However, increase temperature to 700 oC leads to bigger crystal particle size and decreased cation-order, thus higher resistance and deteriorated electrochemical properties. The sample prepared at optimized temperature of 650 oC presents a remarkable improved electrochemical performance. It delivers an initial capacity of 125.1 mAhg-1 at 0.2C, 95 mAhg-1 at 5C, and a capacity retention of 98.0% after 30 cycles.

Carbon Nanotube Paper as Anode for Flexible Lithium-Ion Battery

NANO ◽  
2016 ◽  
Vol 11 (11) ◽  
pp. 1650120 ◽  
Author(s):  
Xiaogang Sun ◽  
Zhenhong Liu ◽  
Neng Li ◽  
Xiaoyong Wu ◽  
Yanyan Nie ◽  
...  
Keyword(s):  
Carbon Nanotube ◽  
Electrochemical Performance ◽  
Lithium Ion Battery ◽  
Electrochemical Impedance ◽  
Negative Electrode ◽  
Lithium Ion ◽  
Charge Transfer Resistance ◽  
Electrochemical Performances ◽  
Multiwalled Carbon ◽  
Transfer Resistance

In this investigation, multiwalled carbon nanotube (MWCNT) paper consists of MWCNTs and cellulose was fabricated by traditional paper-making method. It was applied directly as negative electrode in flexible lithium ion battery to replace ordinary electrode which is combined with anode material and current collector. The electrochemical performances of the as-produced MWCNT paper (AMP) and carbonized MWCNT paper (CMP) were evaluated in this study. The morphology and structure of the MWCNT papers were observed by scanning electron microscopy (SEM). The electrochemical performance of the battery was operated by cell test and electrochemical impedance spectroscopy (EIS) measurement. The charging and discharging results indicated that the CMP behaves with higher capacity than AMP. And the EIS analysis showed that a lower charge transfer resistance can be obtained in the CMP. The excellent electrochemical performance verifies the feasibility of MWCNT papers as a promising candidate for the anode in flexible lithium ion battery.

scholarly journals Role of TiO2 Phase Composition Tuned by LiOH on The Electrochemical Performance of Dual-Phase Li4Ti5O12-TiO2 Microrod as an Anode for Lithium-Ion Battery

Energies ◽  
2020 ◽  
Vol 13 (20) ◽  
pp. 5251
Author(s):  
Lukman Noerochim ◽  
Wahyu Caesarendra ◽  
Abdulloh Habib ◽  
Widyastuti ◽  
Suwarno ◽  
...  
Keyword(s):  
Phase Composition ◽  
Electrochemical Performance ◽  
Specific Capacity ◽  
Rate Capability ◽  
Lithium Ion ◽  
Charge Transfer Resistance ◽  
Dual Phase ◽  
Retention Capacity ◽  
Transfer Resistance ◽  
Tio2 Phase

In this study, a dual-phase Li4Ti5O12-TiO2 microrod was successfully prepared using a modified hydrothermal method and calcination process. The stoichiometry of LiOH as precursor was varied at mol ratio of 0.9, 1.1, and 1.3, to obtain the appropriate phase composition between TiO2 and Li4Ti5O12. Results show that TiO2 content has an important role in increasing the specific capacity of electrodes. The refinement of X-ray diffraction patterns by Rietveld analysis confirm that increasing the LiOH stoichiometry suppresses the TiO2 phase. In the scanning electron microscopy images, the microrod morphology was formed after calcination with diameter sizes ranging from 142.34 to 260.62 nm and microrod lengths ranging from 5.03–7.37 μm. The 0.9 LiOH sample shows a prominent electrochemical performance with the largest specific capacity of 162.72 mAh/g and 98.75% retention capacity achieved at a rate capability test of 1 C. This finding can be attributed to the appropriate amount of TiO2 that induced the smaller crystallite size, and lower charge transfer resistance, enhancing the lithium-ion insertion/extraction process and faster diffusion kinetics.

scholarly journals Enhanced Activity of Hierarchical Nanostructural Birnessite-MnO2-Based Materials Deposited onto Nickel Foam for Efficient Supercapacitor Electrodes

Nanomaterials ◽  
2020 ◽  
Vol 10 (10) ◽  
pp. 1933
Author(s):  
Shang-Chao Hung ◽  
Yi-Rong Chou ◽  
Cheng-Di Dong ◽  
Kuang-Chung Tsai ◽  
Wein-Duo Yang
Keyword(s):  
Electrochemical Performance ◽  
Electrode Materials ◽  
Electrochemical Impedance ◽  
Nickel Foam ◽  
Rate Capability ◽  
Multiwall Carbon Nanotubes ◽  
Charge Transfer Resistance ◽  
Transfer Resistance ◽  
Pore Size Distributions ◽  
Hierarchical Porous

Hierarchical porous birnessite-MnO2-based nanostructure composite materials were prepared on a nickel foam substrate by a successive ionic layer adsorption and reaction method (SILAR). Following composition with reduced graphene oxide (rGO) and multiwall carbon nanotubes (MWCNTs), the as-obtained MnO2, MnO2/rGO and MnO2/rGO-MWCNT materials exhibited pore size distributions of 2–8 nm, 5–15 nm and 2–75 nm, respectively. For the MnO2/rGO-MWCNT material in particular, the addition of MWCNT and rGO enhanced the superb distribution of micropores, mesopores and macropores and greatly improved the electrochemical performance. The as-obtained MnO2/rGO-MWCNT/NF electrode showed a specific capacitance that reached as high as 416 F·g−1 at 1 A·g−1 in 1 M Na2SO4 aqueous electrolyte and also an excellent rate capability and high cycling stability, with a capacitance retention of 85.6% after 10,000 cycles. Electrochemical impedance spectroscopy (EIS) analyses showed a low resistance charge transfer resistance for the as-prepared MnO2/rGO-MWCNT/NF nanostructures. Therefore, MnO2/rGO-MWCNT/NF composites were successfully synthesized and displayed enhanced electrochemical performance as potential electrode materials for supercapacitors.

scholarly journals Corrosion Inhibitive Action and Adsorption Behaviour of Justicia Secunda Leaves Extract as an Eco‐Friendly Inhibitor for Aluminium in Acidic Media

2021 ◽  
Vol 11 (5) ◽  
pp. 13019-13030
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Weight Loss ◽  
Electrochemical Impedance ◽  
Physical Adsorption ◽  
Charge Transfer Resistance ◽  
Aluminum Surface ◽  
Protective Film ◽  
Transfer Resistance ◽  
Scanning Electron

The extract of Justicia secunda (JS) leaves was investigated as an eco‐friendly corrosion inhibitor of aluminum in 0.5 M HCl using weight loss, electrochemical impedance spectroscopy (EIS), potentiodynamic polarization (PDP), and scanning electron microscopy (SEM) techniques. The inhibitor concentrations used ranged from 50 to 250 ppm at 30, 40, and 50oC. Results show that Justicia secunda acts as a good inhibitor for aluminum. Its efficiency increased with increasing inhibitor concentration but decreased with increasing temperature. Maximum inhibition efficiency as high as 94.3% was found at 30°C for 250 ppm of the inhibitor with the weight loss technique. Tafel polarization results show that the extract acts as a mixed-type inhibitor. The Nyquist plots indicated decreasing double-layer capacitance and increasing charge transfer resistance on increasing JS concentration. The inhibition action occurred through the physical adsorption of the extract on the aluminum surface. The adsorption process was found to follow Langmuir adsorption isotherm. The formation of a protective film on the metal surface was confirmed by scanning electron microscopy.

scholarly journals Enhanced Structural Integrity and Electrochemical Performance of AlPO4-Coated MoO2 Anode Material for Lithium-Ion Batteries

2014 ◽  
Vol 2014 ◽  
pp. 1-12 ◽  
Author(s):  
José I. López-Pérez ◽  
Edwin O. Ortiz-Quiles ◽  
Khaled Habiba ◽  
Mariel Jiménez-Rodríguez ◽  
Brad R. Weiner ◽  
...  
Keyword(s):  
Surface Modification ◽  
Electrochemical Performance ◽  
Anode Material ◽  
Structural Integrity ◽  
Electrochemical Impedance ◽  
Lattice Structure ◽  
Rate Capability ◽  
Lithium Ion ◽  
Microscopy Imaging ◽  
Voltage Range

AlPO4 nanoparticles were synthesized via chemical deposition method and used for the surface modification of MoO2 to improve its structural stability and electrochemical performance. Structure and surface morphology of pristine and AlPO4-coated MoO2 anode material were characterized by electron microscopy imaging (SEM and TEM) and X-ray diffraction (XRD). AlPO4 nanoparticles were observed, covering the surface of MoO2. Surface analyses show that the synthesized AlPO4 is amorphous, and the surface modification with AlPO4 does not result in a distortion of the lattice structure of MoO2. The electrochemical properties of pristine and AlPO4-coated MoO2 were characterized in the voltage range of 0.01–2.5 V versus Li/Li+. Cyclic voltammetry studies indicate that the improvement in electrochemical performance of the AlPO4-coated anode material was attributed to the stabilization of the lattice structure during lithiation. Galvanostatic charge/discharge and electrochemical impedance spectroscopy (EIS) studies reveal that the AlPO4 nanoparticle coating improves the rate capability and cycle stability and contributes toward decreasing surface layer and charge-transfer resistances. These results suggest that surface modification with AlPO4 nanoparticles suppresses the elimination of oxygen vacancies in the lattice structure during cycling, leading to a better rate performance and cycle life.

Hydrothermal synthesis MoO3@CoMoO4 hybrid as an anode material for high performance lithium rechargeable batteries

2019 ◽  
Vol 12 (01) ◽  
pp. 1850104 ◽  
Author(s):  
Jinggao Wu ◽  
Qi Lai ◽  
Canyu Zhong
Keyword(s):  
Current Density ◽  
High Performance ◽  
High Current Density ◽  
Rate Capability ◽  
Lithium Ion ◽  
Charge Transfer Resistance ◽  
Rechargeable Batteries ◽  
Transfer Resistance ◽  
Lithium Rechargeable Batteries ◽  
One Step

MoO3@CoMoO4 hybrid is fabricated by a facile one-step hydrothermal method and is used as anode for lithium-ion battery (LIB). Compared to pristine MoO3, galvanostatic charge–discharge tests show that the hybrid electrode delivered a remarkable rate capability of 586.69[Formula: see text]mAh[Formula: see text]g[Formula: see text] at the high current density of 1000[Formula: see text]mA[Formula: see text]g[Formula: see text] and a greatly enhanced cyclic capacity of 887.36[Formula: see text]mA[Formula: see text]h[Formula: see text]g[Formula: see text] after 140 cycles at the current density of 200[Formula: see text]mA[Formula: see text]g[Formula: see text] (with capacity retention, 85.3%). The superior electrochemical properties could be ascribed to the synergistic effect of MoO3 and CoO nanostructure that results in the lower charge transfer resistance and the higher Li[Formula: see text] diffusion coefficient, thus leading to high performance Li[Formula: see text] reversibility storage.

Sign in / Sign up

Export Citation Format

Share Document