Electrochemical Characterization of Graphene–LiMn2O4 Composite Cathode Material for Aqueous Rechargeable Lithium Batteries

2021 ◽  
Vol 23 (09) ◽  
pp. 967-980
Author(s):  
K.C. Mahesh ◽  
◽  
G.S. Suresh ◽  
Keyword(s):  
Cathode Material ◽  
Charge Transfer Resistance ◽  
Active Surface Area ◽  
Electrochemical Performances ◽  
Composite Electrodes ◽  
Rechargeable Lithium Batteries ◽  
Lithium Storage ◽  
Transfer Resistance ◽  
Graphene Layers ◽  
Active Nanoparticles

A series of graphene– LiMn2O4 composite electrodes were prepared by physical mixing of graphene powder and LiMn2O4 cathode material. LiMn2O4was synthesized by reactions under autogenic pressure at elevated temperature method. CV, galvanostatic charge-discharge experiments and EIS studies revealed that the addition of graphene significantly decreases the charge-transfer resistance of LiMn2O4 electrodes. 5 wt. % graphene–LiMn2O4 composite electrode exhibits better electrochemical performance by increasing the reaction reversibility and capacity compared to that of the pristine LiMn2O4 electrode. Improved electrochemical performances are thus achieved, owing to the synergic effect between graphene and the LiMn2O4 active nanoparticles. The ultrathin flexible graphene layers can provide a support for anchoring well-dispersed active cathode particles and work as a highly conductive matrix for enabling good contact between them. At the same time, the anchoring of active nanoparticles on graphene effectively reduces the degree of restacking of graphene sheets and consequently keeps a highly active surface area which increases the lithium storage capacity and cycling performance.

Facile Preparation of NiO/Ni Nanocomposite and its Electrochemical Capacitive Behaviors

2011 ◽  
Vol 306-307 ◽  
pp. 134-138 ◽  
Author(s):  
Wei Dong Yin ◽  
Gui Lian Li ◽  
Xian Ming Liu
Keyword(s):  
Specific Capacitance ◽  
Oxidation Process ◽  
Aqueous Electrolyte ◽  
High Specific Capacitance ◽  
Cycling Performance ◽  
Charge Transfer Resistance ◽  
Electrochemical Performances ◽  
Composite Electrodes ◽  
Galvanostatic Charge ◽  
Transfer Resistance

NiO/Ni nanocomposites were prepared by chemically reduction-oxidation process in tetra-ethylene glycol (TEG) solution. The structure and morphology of the samples were examined by XRD and SEM. The results indicated the composite consisted of NiO and Ni and exhibited spherical morphology with diameter of 50-200 nm. The electrochemical performances of composite electrodes used in electrochemical capacitors were studied. The electrochemical measurements were carried out using cyclic voltammetry, galvanostatic charge/discharge and impedance spectroscopy in 6M KOH aqueous electrolyte using three-electrode Swagelok systems. The results showed that the composite had a high specific capacitance and excellent capacitive behavior. The specific capacitance of the composite decreased to 192F/g after 500 cycles. Due to the existance of Ni, the charge transfer resistance is lower than 1Ω. It revealed that the composite exhibited good cycling performance.

Facile Synthesis of Polypyrrole Nanofibers/Co-MOF Composite and Its Lithium Storage Properties

2020 ◽  
Vol 12 (4) ◽  
pp. 486-491
Author(s):  
Jinlei Wang ◽  
Na Cao ◽  
Huiling Du ◽  
Xian Du ◽  
Hai Lu ◽  
...  
Keyword(s):  
Electrode Materials ◽  
Rate Capability ◽  
Lithium Ion ◽  
Reversible Capacity ◽  
Cycling Performance ◽  
Charge Transfer Resistance ◽  
Growth Strategy ◽  
Composite Electrodes ◽  
Lithium Storage ◽  
Transfer Resistance

Metal-organic frameworks (MOFs) have recently emerged as promising electrode materials for lithium-ion batteries (LIBs). However, poor electrical conductivity in most MOFs limits their electrochemical performance. In this work, the integration of flaky cobalt 1,4-benzenedicarboxylate (Co-BDC) MOF with conductive polypyrrole (PPy) nanofibers via in-situ growth strategy was explored for developing novel anode materials for LIBs. Electrochemical studies showed that PPy/Co-BDC composites exhibited enhanced cycling performance (a reversible capacity of ca. 364 mA h g–1 at a current density of 50 mA g–1 after 100 cycles) and rate capability, com- pared with the pristine Co-BDC. The well dispersion of Co-BDC on polypyrrole nanofibers and the decrease in charge-transfer resistance of the composite electrodes accounted for the improvement of electrochemical properties.

scholarly journals Synthesis and Characterization of Electrodeposited C-PANI-Pd-Ni Composite Electrocatalyst for Methanol Oxidation

2014 ◽  
Vol 2014 ◽  
pp. 1-8 ◽  
Author(s):  
S. S. Mahapatra ◽  
S. Shekhar ◽  
B. K. Thakur ◽  
H. Priyadarshi
Keyword(s):  
Methanol Oxidation ◽  
Electrocatalytic Activity ◽  
Electrochemical Impedance ◽  
Synergistic Effects ◽  
Catalytic Performance ◽  
Charge Transfer Resistance ◽  
Pani Film ◽  
Composite Electrodes ◽  
Transfer Resistance ◽  
Onset Potential

Electropolymerization of aniline at the graphite electrodes was achieved by potentiodynamic method. Electrodeposition of Pd (C-PANI-Pd) and Ni (C-PANI-Ni) and codeposition of Pd-Ni (C-PANI-Pd-Ni) microparticles into the polyaniline (PANI) film coated graphite (C-PANI) were carried out under galvanostatic control. The morphology and composition of the composite electrodes were obtained using scanning electron microscopy (SEM) and energy dispersive X-ray analysis (EDX) techniques. The electrochemical behavior and electrocatalytic activity of the electrode were characterized using cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), and chronoamperometric (CA) methods in acidic medium. The C-PANI-Pd-Ni electrode showed an improved catalytic performance towards methanol oxidation in terms of lower onset potential, higher anodic oxidation current, greater stability, lower activation energy, and lower charge transfer resistance. The enhanced electrocatalytic activity might be due to the greater permeability of C-PANI films for methanol molecules, better dispersion of Pd-Ni microparticles into the polymer matrixes, and the synergistic effects between the dispersed metal particles and their matrixes.

scholarly journals New Generation of Electrochemical Sensors Based on Multi-Walled Carbon Nanotubes

2018 ◽  
Vol 8 (10) ◽  
pp. 1925 ◽  
Author(s):  
Thiago Oliveira ◽  
Simone Morais
Keyword(s):  
Carbon Nanotubes ◽  
Electrochemical Sensors ◽  
Industrial Applications ◽  
Charge Transfer Resistance ◽  
Active Surface Area ◽  
Synthesis Methods ◽  
Transfer Resistance ◽  
Multi Walled Carbon Nanotubes ◽  
New Generation ◽  
Walled Carbon Nanotubes

Multi-walled carbon nanotubes (MWCNT) have provided unprecedented advances in the design of electrochemical sensors. They are composed by sp2 carbon units oriented as multiple concentric tubes of rolled-up graphene, and present remarkable active surface area, chemical inertness, high strength, and low charge-transfer resistance in both aqueous and non-aqueous solutions. MWCNT are very versatile and have been boosting the development of a new generation of electrochemical sensors with application in medicine, pharmacology, food industry, forensic chemistry, and environmental fields. This work highlights the most important synthesis methods and relevant electrochemical properties of MWCNT for the construction of electrochemical sensors, and the numerous configurations and successful applications of these devices. Thousands of studies have been attesting to the exceptional electroanalytical performance of these devices, but there are still questions in MWCNT electrochemistry that deserve more investigation, aiming to provide new outlooks and advances in this field. Additionally, MWCNT-based sensors should be further explored for real industrial applications including for on-line quality control.

Ultrathin nickel boride nanosheets anchored on functionalized carbon nanotubes as bifunctional electrocatalysts for overall water splitting

2019 ◽  
Vol 7 (2) ◽  
pp. 764-774 ◽  
Author(s):  
Xuncai Chen ◽  
Zixun Yu ◽  
Li Wei ◽  
Zheng Zhou ◽  
Shengli Zhai ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Charge Transfer ◽  
Active Surface ◽  
Charge Transfer Resistance ◽  
Active Surface Area ◽  
Transfer Resistance ◽  
Functionalized Carbon Nanotubes ◽  
Electrochemically Active ◽  
Metal Borides ◽  
Electrochemically Active Surface

Carbon nanotubes increase electrochemically active surface area and reduce charge transfer resistance of transition metal borides.

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).

scholarly journals From Allergens to Battery Anodes: Nature-Inspired, Pollen Derived Carbon Architectures for Room- and Elevated- Temperature Li-ion Storage

2016 ◽  
Vol 6 (1) ◽  
Author(s):  
Jialiang Tang ◽  
Vinodkumar Etacheri ◽  
Vilas G. Pol
Keyword(s):  
Photoelectron Spectroscopy ◽  
Electrochemical Impedance ◽  
Lithium Ion ◽  
Charge Transfer Resistance ◽  
High Rate ◽  
Energy Storage Devices ◽  
Lithium Storage ◽  
Transfer Resistance ◽  
Carbonaceous Particles ◽  
X Ray

Abstract The conversion of allergic pollen grains into carbon microstructures was carried out through a facile, one-step, solid-state pyrolysis process in an inert atmosphere. The as-prepared carbonaceous particles were further air activated at 300 °C and then evaluated as lithium ion battery anodes at room (25 °C) and elevated (50 °C) temperatures. The distinct morphologies of bee pollens and cattail pollens are resembled on the final architecture of produced carbons. Scanning Electron Microscopy images shows that activated bee pollen carbon (ABP) is comprised of spiky, brain-like and tiny spheres; while activated cattail pollen carbon (ACP) resembles deflated spheres. Structural analysis through X-ray diffraction and Raman spectroscopy confirmed their amorphous nature. X-ray photoelectron spectroscopy analysis of ABP and ACP confirmed that both samples contain high levels of oxygen and small amount of nitrogen contents. At C/10 rate, ACP electrode delivered high specific lithium storage reversible capacities (590 mAh/g at 50 °C and 382 mAh/g at 25 °C) and also exhibited excellent high rate capabilities. Through electrochemical impedance spectroscopy studies, improved performance of ACP is attributed to its lower charge transfer resistance than ABP. Current studies demonstrate that morphologically distinct renewable pollens could produce carbon architectures for anode applications in energy storage devices.

scholarly journals A Low Cost Fe3O4–Activated Biochar Electrode Sensor by Resource Utilization of Excess Sludge for Detecting Tetrabromobisphenol A

Micromachines ◽  
2022 ◽  
Vol 13 (1) ◽  
pp. 115
Author(s):  
Suxing Luo ◽  
Meizhi Yang ◽  
Yuanhui Wu ◽  
Jiang Li ◽  
Jun Qin ◽  
...  
Keyword(s):  
Electrochemical Sensors ◽  
Low Cost ◽  
Active Surface ◽  
Charge Transfer Resistance ◽  
Tetrabromobisphenol A ◽  
Active Surface Area ◽  
Excess Sludge ◽  
Transfer Resistance ◽  
Activated Biochar ◽  
Bet Analysis

Owing to its ubiquity in natural water systems and the high toxicity of its accumulation in the human body, it is essential to develop simple and low-cost electrochemical sensors for the determination of 3,3′,5,5′-tetrabromobisphenol A (TBBPA). In this work, Fe3O4–activated biochar, which is based on excess sludge, was prepared and characterized using scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), Fourier transform infrared spectroscopy (FTIR) and BET analysis to analyze its basic features. Subsequently, it was used to fabricate an electrochemical sensor for the detection of TBBPA. The electrochemical test results revealed that the Fe3O4–activated biochar film exhibited a larger active surface area, a lower charge transfer resistance and a higher accumulation efficiency toward TBBPA. Consequently, the peak current of TBBPA was significantly enhanced on the surface of the Fe3O4–activated biochar. The TBBPA sensing platform developed using the Fe3O4–activated biochar composite film, with relatively a lower detection limit (3.2 nM) and a wider linear range (5–1000 nM), was successfully utilized to determine TBBPA levels in water samples. In summary, the effective application of Fe3O4–activated biochar provided eco-friendly and sustainable materials for the development of a desirable high-sensitivity sensor for TBBPA detection.

Enhanced Electrochemical Performances of LiFePO4/C Cathode Materials by Deposited with Ge Film

2014 ◽  
Vol 936 ◽  
pp. 480-485
Author(s):  
Yan Dan Huang ◽  
Ying Bin Lin ◽  
Zhi Gao Huang
Keyword(s):  
Impedance Spectroscopy ◽  
Electrochemical Impedance ◽  
Active Material ◽  
Rate Capability ◽  
Film Surface ◽  
Charge Transfer Resistance ◽  
Electrochemical Performances ◽  
Cyclic Voltammograms ◽  
Transfer Resistance ◽  
Surface Modified

LiFePO4/C-Ge electrodes were prepared with vacuum thermal evaporation deposition by depositing Ge films on as-prepared LiFePO4/C electrodes. The effect of Ge film on the electrochemical performances of LiFePO4/C cells was investigated systematically by charge/discharge testing, cyclic voltammograms and AC impedance spectroscopy, respectively. It was found that Ge-film-surface modified LiFePO4/C showed excellent electrochemical performances compared to that of the pristine one in terms of cyclability and rate capability. At 60°C, LiFePO4/C-Ge film exhibited outstanding cyclability with less than 5% capacity fade after 50 cycles while the pristine one suffers 15%. Analysis from the electrochemical measurements showed that the presence of Ge film on the LiFePO4/C electrode would protect active material from HF generated by the decomposition of LiPF6 in the electrolyte and stabilize the surface structure of active material during the charge and discharge cycle. Electrochemical impedance spectroscopy (EIS) results indicated that Ge film mainly reduced the charge transfer resistance Rct of LiFePO4/C electrode, resulting from the suppression of the solid electrolyte interfacial (SEI) film.

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