scholarly journals Enhancement of the Electrochemical Performance of LiNi1/3Co1/3Mn1/3O2 Cathode Material by Double-Layer Coating with Graphene Oxide and SnO2 for Lithium-Ion Batteries

2019 ◽  
Vol 2019 ◽  
pp. 1-10
Author(s):  
Yuxin Ma ◽  
Ping Cui ◽  
Dan Zhan ◽  
Bing Gan ◽  
Youliang Ma ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Graphene Oxide ◽  
Cathode Material ◽  
Electrochemical Impedance ◽  
Coating Layer ◽  
Rate Capability ◽  
Electrode Polarization ◽  
Transfer Resistance ◽  
X Ray ◽  
Double Coating

The graphene oxide-coated SnO2-Li1/3Co1/3Mn1/3O2 (GO-SnO2-NCM) cathode material was successfully synthesized via a facile wet chemical method. The pristine NCM and GO-SnO2-NCM were characterized by X-ray diffraction, scanning electron microscopy, energy-dispersive spectroscopy, transmission electron microscopy, and X-ray photoelectron spectroscopy. The results showed that the double-coating layer did not destroy the NCM crystal structure, with multiple nano-SnO2 particles and GO uniformly covering the NCM surface. Electrochemical tests indicated that GO-SnO2-NCM exhibited excellent cycling performance, with 90.7% capacity retention at 1 C after 100 cycles, which was higher than 74.3% for the pristine NCM at the same cycle. The rate capability showed that the double-coating layer enhanced surface electronic–ionic transport. Electrochemical impedance spectroscopy results confirmed that the GO-SnO2-coating layer effectively suppressed the increased electrode polarization and charge transfer resistance during cycling.

Ternary Composite of Molybdenum Disulfide-Graphene Oxide-Polyaniline for Supercapacitor

2021 ◽  
Author(s):  
Ke Qu ◽  
Yuqi Bai ◽  
Miao Deng
Keyword(s):  
Graphene Oxide ◽  
Molybdenum Disulfide ◽  
Photoelectron Spectroscopy ◽  
Electrochemical Impedance ◽  
Light Emitting Diode ◽  
Rate Capability ◽  
Energy Storage And Conversion ◽  
Carbon Paper ◽  
Power Sources ◽  
X Ray

Abstract The ever-increasing need for small and lightweight power sources for use in portable or wearable electronic devices has spurred the development of supercapacitors as a promising energy storage and conversion system. In this work, a simple, facile and easy-to-practice method has been developed to employ carbon paper (CP) as the support to coat molybdenum disulfide (MoS2) and graphene oxide (GO), followed by electrodeposition of polyaniline (PANI) to render CP/MoS2-GO-PANI. The preparation parameters, such as amounts of MoS2, GO and number of aniline electropolymerization cycles, have been optimized to render CP/MoS2-GO-PANI the best capacitive performance. The as-prepared optimal CP/MoS2-GO-PANI is characterized by X-ray powder diffraction, scanning electron microscopy, energy-dispersive spectroscopy, and X-ray photoelectron spectroscopy. The supercapacitive properties of CP/MoS2-GO-PANI as an electrode have been evaluated electrochemically via cyclic voltammetry, galvanostatic charge/discharge, and electrochemical impedance spectroscopy testing. CP/MoS2-GO-PANI delivers a specific capacitance of 255.1 F/g at 1.0 A/g and exhibits excellent rate capability under larger current densities. Moreover, a symmetrical supercapacitor is assembled and three are connected in series to power a light-emitting diode for ~15 minutes, demonstrating the promising application potential of CP/MoS2-GO-PANI-based supercapacitor.

scholarly journals Improved Electrochemical Performance of Li1.25Ni0.2Co0.333Fe0.133Mn0.333O2 Cathode Material Synthesized by the Polyvinyl Alcohol Auxiliary Sol-Gel Process for Lithium-Ion Batteries

2018 ◽  
Vol 2018 ◽  
pp. 1-7
Author(s):  
He Wang ◽  
Mingning Chang ◽  
Yonglei Zheng ◽  
Ningning Li ◽  
Siheng Chen ◽  
...  
Keyword(s):  
Polyvinyl Alcohol ◽  
Cathode Material ◽  
Discharge Capacity ◽  
Electrochemical Impedance ◽  
Coulombic Efficiency ◽  
Sol Gel ◽  
Rate Capability ◽  
Lithium Ion ◽  
Transfer Resistance ◽  
Sol Gel Process

A lithium-rich manganese-based cathode material, Li1.25Ni0.2Co0.333Fe0.133Mn0.333O2, was prepared using a polyvinyl alcohol (PVA)-auxiliary sol-gel process using MnO2 as a template. The effect of the PVA content (0.0–15.0 wt%) on the electrochemical properties and morphology of Li1.25Ni0.2Co0.333Fe0.133Mn0.333O2 was investigated. Analysis of Li1.25Ni0.2Co0.333Fe0.133Mn0.333O2 X-ray diffraction patterns by RIETAN-FP program confirmed the layered α-NaFeO2 structure. The discharge capacity and coulombic efficiency of Li1.25Ni0.2Co0.333Fe0.133Mn0.333O2 in the first cycle were improved with increasing PVA content. In particular, the best material reached a first discharge capacity of 206.0 mAhg−1 and best rate capability (74.8 mAhg−1 at 5 C). Meanwhile, the highest capacity retention was 87.7% for 50 cycles. Finally, electrochemical impedance spectroscopy shows that as the PVA content increases, the charge-transfer resistance decreases.

Electrochemical Properties of Nanocrystalline Y2-xPrxRu2O7 Pyrochlore for Electrodic Application in IT-SOFCS

2006 ◽  
Vol 972 ◽  
Author(s):  
Chiara Abate ◽  
Keith Duncan ◽  
Enrico Traversa ◽  
Eric Wachsman
Keyword(s):  
Cathode Material ◽  
Phase Boundary ◽  
Electrochemical Impedance ◽  
Charge Transfer Resistance ◽  
Nanocrystalline Powders ◽  
Precipitation Method ◽  
Electrode Polarization ◽  
Transfer Resistance ◽  
Triple Phase Boundary ◽  
Co Precipitation

AbstractNanocrystalline powders of Y2-xPrxRu2O7 were prepared by a co-precipitation method, and were tested as electrode on ESB and GDC electrolytes by electrochemical impedance spectroscopy in the 300-750°C temperatures range. The electrode polarization was studied as a function of the amount of praseodymium in the cathode material. Both systems, Y2-xPrxRu2O7/ESB and Y2-xPrxRu2O7/GDC, showed a similar variation of the electrode area specific resistance (ASR). Y1.5Pr0.5Ru2O7 cathode material presented the best performance, with ASR value of 0.19 Ωcm2 on ESB and 4.23 Ωcm2 on GDC at 700°C. Furthermore, the change in ASR with the oxygen partial pressure suggested that the rate limiting step is the surface diffusion of the adsorbed oxygen at the electrode surface to the triple-phase boundary. Thus, the low value of resistivity of the Y1.5Pr0.5Ru2O7 in contact with ESB results from a much lower charge transfer resistance compared to the Y2-xPrxRu2O7/GDC system, and a partial solid diffusion at the interface electrode/electrolyte that increases the effective triple phase boundary length. This suggests that Y2-xPrxRu2O7 is a promising material for cathode application in ESB-based electrolyte for intermediate temperature solid oxide fuel cells (IT-SOFCs).

Effect of Zn2+ and F− Co-Modification on the Structure and Electrochemical Performance of Li4Ti5O12 Anode Material

NANO ◽  
2017 ◽  
Vol 12 (05) ◽  
pp. 1750054 ◽  
Author(s):  
Aijia Wei ◽  
Wen Li ◽  
Lihui Zhang ◽  
Xiaohui Li ◽  
Xue Bai ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Photoelectron Spectroscopy ◽  
Coating Layer ◽  
Rate Capability ◽  
Precipitation Method ◽  
Charge Capacity ◽  
X Ray ◽  
Modification Process ◽  
Co Precipitation ◽  
A Charge

Zn[Formula: see text] and F[Formula: see text] ions are successfully used to modify pure Li4Ti5O[Formula: see text] via a co-precipitation method followed by calcination at 400[Formula: see text]C for 5[Formula: see text]h in an Ar atmosphere in order to further investigate the reaction mechanism of the fluoride modification process. Zn[Formula: see text] and F[Formula: see text] co-modified Li4Ti5O[Formula: see text] samples are characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS) and electrochemical measurements. After the modification process, no ZnF2 coating layer is formed on the surface of Li4Ti5O[Formula: see text], instead, F[Formula: see text] ions react with Li4Ti5O[Formula: see text] to generate a new phase, composed of a small amount of anatase TiO2, rutile TiO2, LiF, and Zn[Formula: see text] ions are suspected to form a ZnO coating layer on Li4Ti5O[Formula: see text] particles. The electrolyte reduction decomposition is suppressed in Zn[Formula: see text] and F[Formula: see text] co-modified Li4Ti5O[Formula: see text] due to the ZnO coating layer. 1[Formula: see text]wt.% Zn[Formula: see text] and F[Formula: see text] co-modified Li4Ti5O[Formula: see text] exhibits the best rate capability, which leads to a charge capacity of 236.7, 227.8, 222.1, 202.7, 188.9 and 150.7[Formula: see text]mAh g[Formula: see text] at 0.2C, 0.5C, 1C, 3C, 5C and 10C, respectively, between 0[Formula: see text]V and 3[Formula: see text]V. Furthermore, 1[Formula: see text]wt.% Zn[Formula: see text] and F[Formula: see text] co-modified Li4Ti5O[Formula: see text] exhibits 96.0% charge capacity retention at 3C rate after 200 cycles, which is significantly higher than that of pure Li4Ti5O[Formula: see text] (78.4%).

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.

scholarly journals Doping and Surface Modification Enhance the Applicability of Nanostructured Fullerene-MWCNT Hybrid Draped LiNi0.1Mg0.1Co0.8O2 As High Efficient Cathode Material for Lithium-Ion Batteries

2021 ◽  
Author(s):  
Arockia Shyamala Paniyarasi S ◽  
Suja S K ◽  
Nimma Elizabeth R
Keyword(s):  
Electron Microscopy ◽  
Diffusion Coefficient ◽  
Surface Modification ◽  
Electrochemical Performance ◽  
Cathode Material ◽  
Structural Stability ◽  
Cathode Materials ◽  
Transfer Resistance ◽  
X Ray ◽  
High Efficient

Abstract Development of high performance cathode materials, layer-structured ternary LiNi x Co y M 1-x-y O 2 cathode materials have attracted much attention owing to their larger capacity and higher energy density.Persistent efforts have been devoted to tackling certain issues like low electronic conductivity and poor structural stability. Dual strategy of Mg doping and surface modification of the cathode material was adopted to improve the performance of the battery. Fullerene-Multi-Walled Carbon Nanotube (MWCNT) hybrid draped LiNi 0.1 Mg 0.1 Co 0.8 O 2 nanocomposite was synthesized by a simple chemical route. The fullerene-MWCNT hybrid modifies the surface of pristine LiNi 0.1 Mg 0.1 Co 0.8 O 2 thereby improves the electrochemical performance and maintains the structural stability of the cathode material. Pristine LiNi 0.1 Mg 0.1 Co 0.8 O 2 and LiNi 0.1 Mg 0.1 Co 0.8 O 2 / fullerene-MWCNT nanocomposite were studied using various advanced characterization techniques such as X-ray diffraction (XRD), Micro-Raman spectroscopy, Field Emission Scanning Electron Microscopy (FESEM), X-ray Photoelectron Spectroscopy (XPS), and High-Resolution Transmission Electron Microscopy (HRTEM). It is found that LiNi 0.1 Mg 0.1 Co 0.8 O 2 particles retain their structural integrity after being enveloped with a fullerene-MWCNT hybrid. The electrochemical performance was investigated with cyclic voltammetry(CV), galvanostaticcharge-discharge(GCD) test and electrochemical impedance spectroscopy(EIS). As prepared LiNi 0.1 Mg 0.1 Co 0.8 O 2 , when deployed in the form of LiNi 0.1 Mg 0.1 Co 0.8 O 2 / fullerene-MWCNT composite exhibits a high specific capacity of 208 mAh g -1 .Fullerene-MWCNT hybrid draped LiNi 0.1 Mg 0.1 Co 0.8 O 2 nanocomposite provides an effective Li + and electron channel that significantly increased the Li-ion diffusion coefficient and reduced the charge transfer resistance. Besides,the lithium diffusion coefficient increased from 5.13 x 10 -13 (Li/LiNi 0.1 Mg 0.1 Co 0.8 O 2 ) to 8.313 x 10 -13 cm 2 s -1 due to the improved kinetics of Li insertion/extraction process in Li/LiNi 0.1 Mg 0.1 Co 0.8 O 2 +fullerene-MWCNT cell.

Electroanalytical characterization of F-doped MoS2 cathode material for rechargeable magnesium battery

2019 ◽  
Vol 12 (03) ◽  
pp. 1950041 ◽  
Author(s):  
Gundu Venkateswarlu ◽  
Devarapaga Madhu ◽  
Jetti Vatsala Rani
Keyword(s):  
Cathode Material ◽  
Photoelectron Spectroscopy ◽  
Electrochemical Impedance ◽  
Synergetic Effect ◽  
Solution Process ◽  
Rate Capability ◽  
X Ray Diffraction ◽  
X Ray ◽  
Effective Performance

Fluorine (F)-doped MoS2 was prepared by F-doping into layered MoS2 via chemical solution process with fluoroboric acid. X-ray photoelectron spectroscopy, field emission scanning electron microscopy, energy dispersive X-ray spectroscopy, and X-ray diffraction were applied to conform the effect of F on the structure. The electrochemical performance was investigated by using cyclic voltammetry, electrochemical impedance spectroscopy, and galvanostatic charge/discharge studies. The F-doped MoS2 as cathode material for rechargeable Mg battery exhibited a good discharge capacity of 55[Formula: see text]mAhg[Formula: see text], with a good rate capability and good cycling stability when compared to pristine B-MoS2. The effective performance of F-doped MoS2 are attributed to the unique structure and synergetic effect between layered MoS2.

scholarly journals Improved Capacity Retention of SiO2-Coated LiNi0.6Mn0.2Co0.2O2 Cathode Material for Lithium-Ion Batteries

2019 ◽  
Vol 9 (18) ◽  
pp. 3671 ◽  
Author(s):  
Xiaoxue Lu ◽  
Ningxin Zhang ◽  
Marcus Jahn ◽  
Wilhelm Pfleging ◽  
Hans J. Seifert
Keyword(s):  
Electron Microscopy ◽  
Cathode Material ◽  
Coating Layer ◽  
Condensation Reaction ◽  
Particle Surface ◽  
Rate Capability ◽  
Lithium Ion ◽  
Shielding Effect ◽  
Sio2 Coating

Surface degradation of Ni-enriched layered cathode material Li[Ni0.6Mn0.2Co0.2]O2 (NMC622) is the main reason that leads to large capacity decay during long-term cycling. In the frame of this research, an amorphous SiO2 coating was applied onto the surface of the commercially available NMC622 powder by a wet coating process, through the condensation reaction of tetraethyl orthosilicate. The chemical composition of the coating layer was analyzed by inductively-coupled plasma. The morphology was studied by scanning electron microscopy and transmission electron microscopy. Electrochemical properties, including cyclic voltammetry, galvanostatic cycling, and rate capability measurements in a half-cell configuration, were tested to compare the electrochemical behavior of the non-coated and coated NMC622 materials. It is shown that the rate performance of the NMC622 materials is not affected by the coating layer. After 700 cycles in the range of 3.0–4.3 V at 2 C discharge, the cells with SiO2-coated NMC622 materials retained 80% of their initial capacity, which is higher than the uncoated ones (74%). Physicochemical characterizations, e.g., XRD and SEM, were performed post-mortem to reveal the stabilizing mechanism of the SiO2-coated NMC622 electrodes after long-term cycling. Based on these results, this is due to the shielding effect of the coating between the NMC622 particle surface and the liquid electrolyte, along with its scavenging effect on HF. SiO2 coating is therefore a facile surface modification method that results in potentially significant enhancement of the cyclic stability of Ni-rich NMC materials.

scholarly journals Modification of Graphene Oxide and Preparation of RuO2 Nanocomposites

2020 ◽  
Author(s):  
Kyeong-Won Park
Keyword(s):  
Electron Microscopy ◽  
Graphene Oxide ◽  
Electrochemical Impedance ◽  
Nano Particles ◽  
Constant Current ◽  
Potential Range ◽  
Electrochemical Characteristics ◽  
X Ray ◽  
Graphene Layers ◽  
13C Nuclear Magnetic Resonance

Graphene-oxide (G) was prepared by the Hummers’ method. A G-COOH layer was synthesised using chloroacetic acid and G. To fabricate carboxylated graphene-RuO2 (G-COORu) nano¬¬-composites, RuO2 nano particles were grown on graphene layers using a one-step thermal method, -COOH(G-COOH), and RuCl3. All materials were characterised using X-ray diffraction, transmission electron microscopy, scanning electron microscopy, 13C-nuclear magnetic resonance as well as X-ray photoelectron, Fourier-transform infrared spectroscopy, and Raman. The electrochemical characteristics of the G-COORu supercapacitors were analysed using electrochemical impedance spectroscopy, cyclic voltammetry, constant current charge–discharge tests, and Nyquist impedance plots. The supercapacitors exhibit a specific capacitance of ~125 F g-1 at 100 mA cm-2 within the potential range of 0–1.0 V. The method used here provides a simple approach for the deposition of RuO2 nano particles on graphene layers and can be widened to the fabrication of other classes of hybrids based on G layers for specific technical applications.

scholarly journals Graphene Oxide Decorated with Titanium Nanoparticles to Reinforce the Anti-Corrosion Performance of Epoxy Coating

Coatings ◽  
2020 ◽  
Vol 10 (2) ◽  
pp. 129 ◽  
Author(s):  
Heng Yuan ◽  
Fugang Qi ◽  
Nie Zhao ◽  
Pengying Wan ◽  
Biao Zhang ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Corrosion Resistance ◽  
Graphene Oxide ◽  
Composite Materials ◽  
Photoelectron Spectroscopy ◽  
Electrochemical Impedance ◽  
Salt Spray ◽  
Corrosion Mechanism ◽  
X Ray ◽  
Ti Particles

Graphene oxide–titanium (GO-Ti) composite materials were fabricated using GO as a precursor and then anchoring nano titanium (Nano-Ti) particles on GO sheets with the help of a silane coupling agent. Then, the coating samples were prepared by dispersing GO, Nano-Ti particles, and GO-Ti in an epoxy resin at a low weight fraction of 1 wt %. The GO-Ti composites were investigated by X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). The dispersibility and anti-corrosion mechanism of the coatings were studied by sedimentation experiments, electrochemical impedance spectroscopy (EIS), SEM, and salt spray tests. The mechanical properties of the coatings were analyzed by friction and wear tests. The results showed that the Nano-Ti particles were successfully loaded on the GO surface by chemical bonds, which made GO-Ti composites exhibit better dispersibility in the epoxy than GO. Compared with Nano-Ti particles and GO, the GO-Ti composite exhibited significant advantages in improving the corrosion resistance of epoxy coatings at the same contents, which was attributed to the excellent dispersibility, inherent corrosion resistance, and sheet structure. Among the different proportions of composite materials, the GO-Ti (2:1) material exhibited the best dispersibility and corrosion resistance. In addition, the composite material also greatly improved the wear resistance of the coating.

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