Research on CuxSy/CoSz/graphene supercapacitor electrode materials

2020 ◽  
Vol 10 (10) ◽  
pp. 1725-1731
Author(s):  
Xiaobo Duan ◽  
Yanhong Ding ◽  
Meng Yu
Keyword(s):  
Hydrothermal Method ◽  
Electrode Materials ◽  
Retention Rate ◽  
Specific Capacity ◽  
Charge Transfer Resistance ◽  
Diffusion Resistance ◽  
Multilayer Graphene ◽  
Supercapacitor Electrode ◽  
Transfer Resistance ◽  
Two Samples

Multilayer graphene was prepared in this study by microwave burst method. Cu9S5/CoS/graphene and CuS/CoS2/graphene composites were obtained by hydrothermal method to regulate the molecular structure and combination of Cu and Co metal sulfides on graphene substrate. Graphite oxide was doped by hydrothermal method, and then Cu9S5/CoS/graphene composite was prepared by microwave explosion method. Raman, SEM and TEM were used to characterize the self-made graphene. Results showed that the multilayer graphene had a bag-like structure which was beneficial to anchor sulfide. Three graphene-based composites were characterized by scanning electron microscopy, X-ray diffraction, energy spectrum analysis and electrochemical properties. Moreover, results showed that CuS/CoS2/graphene had the best electrochemical performance, and its specific capacity reached 324 F/g when the current density was 1 A · g–1, which was much higher than that of the other two samples. Capacity retention rate, interfacial charge transfer resistance and electrolyte diffusion resistance also have advantages.

Effect of Plating Solutions on Supercapacitor Characteristics of MnO2 Films

2010 ◽  
Vol 113-116 ◽  
pp. 1810-1813
Author(s):  
Fang Xiao ◽  
You Long Xu
Keyword(s):  
Electrode Materials ◽  
Electrochemical Impedance ◽  
Equivalent Circuit Model ◽  
Active Surface ◽  
Charge Transfer Resistance ◽  
Electrochemical Impedance Spectrum ◽  
Active Surface Area ◽  
Cyclic Voltammograms ◽  
Supercapacitor Electrode ◽  
Transfer Resistance

MnO2 films were electrodeposited on the Ti substrates by galvanostatic method in various plating solutions, which was MnCl2, Mn(NO3)2, MnSO4 and Mn(CH3COO)2 solutions, respectively. On X-ray diffraction test, Crystal structures of all MnO2 films were associated to α-MnO2 of tetragonal crystal system. Scanning electron microscopy results show that morphologies of MnO2 films were clearly different. Among them, MnO2 film prepared in Mn(CH3COO)2 solution presented a lot of cracks and holes. According to electrochemical impedance spectrum analysis, this MnO2 film presents the lowest charge-transfer resistance. Additionally, electrochemical active surface areas of MnO2 films were calculated on the basis of equivalent circuit model for impedance data. The result was found that MnO2 film prepared in Mn(CH3COO)2 solution showed the biggest electrochemical active surface area, which was about 382 cm2. Cyclic voltammograms were carried out for all the samples. MnO2 film formed in Mn(CH3COO)2 solution showed the highest special capacitance of 230 F g-1. The results suggest that Mn(CH3COO)2 solution is suitable for electrodepositing MnO2 film using supercapacitor electrode materials.

scholarly journals Carbon-Coated SnO2/Ti3C2 Composites with Enhanced Lithium Storage Performance

2019 ◽  
Vol 2019 ◽  
pp. 1-10
Author(s):  
Zijing Wang ◽  
Fen Wang ◽  
Kaiyu Liu ◽  
Jianfeng Zhu ◽  
Abdul Waras
Keyword(s):  
Electrode Materials ◽  
Hydrothermal Reaction ◽  
Specific Capacity ◽  
Charge Transfer Resistance ◽  
Two Dimensional ◽  
Lithium Storage ◽  
Transfer Resistance ◽  
Calcination Process ◽  
Carbon Coated ◽  
New Research

Tin-based anode materials including oxides, composites oxides, and tin-based alloys are identified as promising candidates for energy storage attributed to the highest theoretical specific capacity. We introduce Ti3C2-MXene as structural skeletons and amorphous carbon as conductive networks for tin oxide in this work. Herein, carbon-coated kernel-like SnO2 coupling with two-dimensional (2D) layered structure Ti3C2-MXene (C@SnO2/Ti3C2) composites were prepared by a hydrothermal reaction and a further calcination process. The fabricated C@SnO2/Ti3C2 nanocomposites exhibit smaller charge transfer resistance, larger Li+ diffusion coefficient, and better cycling stability than SnO2/Ti3C2 and pure Ti3C2. Most of all, C@SnO2/Ti3C2 nanocomposites display excellent initial capacity of 1531.5 mAh g−1 at current density of 100 mA g−1 and show outstanding rate performance of 540 mAh g−1even after 200 cycles. In our work, we will provide a new research idea for the composite materials of metal oxides and two-dimensional layered materials in the field of electrode materials for 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.

scholarly journals Collaborative Improvement Electrochemical Properties of Supercapacitor Electrodes by Loading MoS2 Nanosheets on Biomass Hierarchical Porous Carbon

2022 ◽  
Author(s):  
Qiao Jing Lin ◽  
Jing Mei Wang ◽  
Jian Hua Chen ◽  
Qian Yang ◽  
Li Jun Fang ◽  
...  
Keyword(s):  
Porous Carbon ◽  
Electrode Materials ◽  
Retention Rate ◽  
Synergistic Effects ◽  
Specific Capacity ◽  
Metal Sulfide ◽  
Mos2 Nanosheets ◽  
Hierarchical Porous Carbon ◽  
Supercapacitor Electrode ◽  
Hierarchical Porous

Abstract MoS2, a typical two-dimensional transition metal sulfide nanomaterial, has attracted much attention for supercapacitor electrode materials due to its high theoretical capacity. Herein, MoS2 nanosheets growing on a hierarchical porous carbon (HPGC) derived from pomelo peel are prepared via hydrothermal method. The curled MoS2 nanosheets uniformly grow and distribute on the conductive hierarchical porous carbon matrix, which made the electrodes materials possess a high specific surface area (320.2 m2/g). Simultaneously, the novel structure enhances the conductivity of MoS2, alleviates capacity attenuation and guarantees the interface stability. Furthermore, the MoS2/HPGC show a great enhancement in supercapacitor performance and deliver a remarkable specific capacitance of 411.4 F/g at the current density of 0.5 A/g. The initial capacitance retention rate is approximately 94.3% after 2000 cycles. It turns out that the synergistic effects between the MoS2 nanosheets and HPGC contribute to high specific capacity, excellent rate performance and ultra-long cycle life. This work provides a new idea for the design and development of MoS2 composites as the electrode materials of supercapacitors.

scholarly journals Effect of nanostructured carbon coatings on the electrochemical performance of Li1.4Ni0.5Mn0.5O2+ x -based cathode materials

2016 ◽  
Vol 7 ◽  
pp. 1960-1970 ◽  
Author(s):  
Konstantin A Kurilenko ◽  
Oleg A Shlyakhtin ◽  
Oleg A Brylev ◽  
Dmitry I Petukhov ◽  
Alexey V Garshev
Keyword(s):  
Diffusion Coefficient ◽  
Charge Transfer ◽  
Specific Capacity ◽  
Charge Transfer Resistance ◽  
Poly Vinyl Alcohol ◽  
Nanostructured Carbon ◽  
Transfer Resistance ◽  
Carbon Coatings ◽  
Lithium Diffusion Coefficient ◽  
Electrochemical Cycling

Nanocomposites of Li1.4Ni0.5Mn0.5O2+ x and amorphous carbon were obtained by the pyrolysis of linear and cross-linked poly(vinyl alcohol) (PVA) in presence of Li1.4Ni0.5Mn0.5O2+ x . In the case of linear PVA, the formation of nanostructured carbon coatings on Li1.4Ni0.5Mn0.5O2+ x particles is observed, while for cross-linked PVA islands of mesoporous carbon are located on the boundaries of Li1.4Ni0.5Mn0.5O2+ x particles. The presence of the carbon framework leads to a decrease of the polarization upon cycling and of the charge transfer resistance and to an increase in the apparent Li+ diffusion coefficient from 10−16 cm2·s−1 (pure Li1.4Ni0.5Mn0.5O2+ x ) to 10−13 cm2·s−1. The nanosized carbon coatings also reduce the deep electrochemical degradation of Li1.4Ni0.5Mn0.5O2+ x during electrochemical cycling. The nanocomposite obtained by the pyrolysis of linear PVA demonstrates higher values of the apparent lithium diffusion coefficient, a higher specific capacity and lower values of charge transfer resistance, which can be related to the more uniform carbon coatings and to the significant content of sp2-hybridized carbon detected by XPS and by Raman spectroscopy.

Electrochemical Properties of Natural and Modified Pyrite

2012 ◽  
Vol 554-556 ◽  
pp. 379-384
Author(s):  
Da Gang Wang ◽  
Li Ren Fan ◽  
Chou Fan
Keyword(s):  
Electrochemical Impedance ◽  
Specific Capacity ◽  
Charge Transfer Resistance ◽  
Fatty Acid Salt ◽  
Transfer Resistance ◽  
Cyclic Voltammetry Measurement ◽  
Mean Grain Size ◽  
Specific Discharge ◽  
Voltage Plateau ◽  
Natural Pyrite

Pyrite utrafine powder was yielded through processing natural pyrite, including gravity separation, flotation and airflow grinding, which the contents of Fe and S are 45.30wt% and 50.95wt% respectively and the mean grain size is 13μm. Pyrite powder modified by fatty acid salt A was investigated by TG/DSC, XPS and XRD. The results indicate that the phase of powder is mostly pyrite FeS2 coating with organic modifier, and S exists in the form of [S2]2- principally on modified pyrite surface. Furthermore, electrochemical impedance spectroscopy, cyclic voltammetry measurement and galvanotactic current charge and discharge methods were applied to exhibit the electrochemical performance of pyrite sample. The results show that modified pyrite has lower charge transfer resistance and higher conductivity than that of natural pyrite, and the specific discharge capacity is as high as 850mAh/g under 0.354A current at room temperature and the cutoff of 0.5V closing to the theoretical specific capacity of pyrite (890mA•h/g), and the voltage plateau is 1.44V.

Graphene-Wrapped FeOOH Nanorods with Enhanced Performance as Lithium-Ion Battery Anode

NANO ◽  
2020 ◽  
pp. 2150005
Author(s):  
Meng Sun ◽  
Zhipeng Cui ◽  
Huanqing Liu ◽  
Sijie Li ◽  
Qingye Zhang ◽  
...  
Keyword(s):  
High Performance ◽  
Electrode Materials ◽  
Electronic Conductivity ◽  
Rate Capability ◽  
Lithium Ion ◽  
Extraction Process ◽  
Hybrid Structure ◽  
Charge Transfer Resistance ◽  
Transfer Resistance ◽  
Distinctive Structure

FeOOH nanorods (NRs) wrapped by reduced graphene oxide (rGO) were fabricated using a facile solvothermal method. When used as anode materials for lithium-ion batteries (LIBs), the FeOOH NRs/rGO composites show a higher capacity (490[Formula: see text]mAh g[Formula: see text] after 100 cycles at a current density of 100[Formula: see text]mA g[Formula: see text] and better rate capability than pure FeOOH NRs. The enhanced electrochemical performance can be ascribed to the hybrid structure of FeOOH and rGO. On one hand, the introduction of rGO can improve electronic conductivity and reduce charge-transfer resistance for electrode materials. On the other hand, the distinctive structure (FeOOH NRs surrounded by flexible rGO) can effectively buffer large volume change during the Li[Formula: see text] insertion/extraction process. Our work provides a feasible strategy to obtain high-performance LIBs.

scholarly journals Electrochemical Characterization of CVD-Grown Graphene for Designing Electrode/Biomolecule Interfaces

Crystals ◽  
2020 ◽  
Vol 10 (4) ◽  
pp. 241
Author(s):  
Keishu Miki ◽  
Takeshi Watanabe ◽  
Shinji Koh
Keyword(s):  
Electrochemical Properties ◽  
Electrode Materials ◽  
Electrochemical Impedance ◽  
Chemical Vapor ◽  
Charge Transfer Resistance ◽  
Monolayer Graphene ◽  
Transfer Resistance ◽  
Graphene Electrode ◽  
Before And After ◽  
Modified Graphene

In research on enzyme-based biofuel cells, covalent or noncovalent molecular modifications of carbon-based electrode materials are generally used as a method for immobilizing enzymes and/or mediators. However, the influence of these molecular modifications on the electrochemical properties of electrode materials has not been clarified. In this study, we present the electrochemical properties of chemical vapor deposition (CVD)-grown monolayer graphene electrodes before and after molecular modification. The electrochemical properties of graphene electrodes were evaluated by cyclic voltammetry and electrochemical impedance measurements. A covalently modified graphene electrode showed an approximately 25-fold higher charge transfer resistance than before modification. In comparison, the electrochemical properties of a noncovalently modified graphene electrode were not degraded by the modification.

scholarly journals Electrochemical Impedance Spectroscopy on the Performance Degradation of LiFePO4/Graphite Lithium-Ion Battery Due to Charge-Discharge Cycling under Different C-Rates

Energies ◽  
2019 ◽  
Vol 12 (23) ◽  
pp. 4507 ◽  
Author(s):  
Yusuke Abe ◽  
Natsuki Hori ◽  
Seiji Kumagai
Keyword(s):  
Charge Transfer ◽  
Electrochemical Impedance Spectroscopy ◽  
Impedance Spectroscopy ◽  
Electrochemical Impedance ◽  
Specific Capacity ◽  
Lithium Ion ◽  
Performance Degradation ◽  
Charge Transfer Resistance ◽  
Transfer Resistance ◽  
Charge Discharge

Lithium-ion batteries (LIBs) using a LiFePO4 cathode and graphite anode were assembled in coin cell form and subjected to 1000 charge-discharge cycles at 1, 2, and 5 C at 25 °C. The performance degradation of the LIB cells under different C-rates was analyzed by electrochemical impedance spectroscopy (EIS) and scanning electron microscopy. The most severe degradation occurred at 2 C while degradation was mitigated at the highest C-rate of 5 C. EIS data of the equivalent circuit model provided information on the changes in the internal resistance. The charge-transfer resistance within all the cells increased after the cycle test, with the cell cycled at 2 C presenting the greatest increment in the charge-transfer resistance. Agglomerates were observed on the graphite anodes of the cells cycled at 2 and 5 C; these were more abundantly produced in the former cell. The lower degradation of the cell cycled at 5 C was attributed to the lowered capacity utilization of the anode. The larger cell voltage drop caused by the increased C-rate reduced the electrode potential variation allocated to the net electrochemical reactions, contributing to the charge-discharge specific capacity of the cells.

Increasing Electrical Conductivity of Free-Standing Sulfurized Polyacrylonitrile Cathode for Lithium–Sulfur Batteries

2020 ◽  
Vol 12 (10) ◽  
pp. 1441-1445
Author(s):  
Huihun Kim ◽  
Seon-Hwa Choe ◽  
Milan K. Sadan ◽  
Changhyeon Kim ◽  
Kwon-Koo Cho ◽  
...  
Keyword(s):  
Electrical Conductivity ◽  
Specific Capacity ◽  
Rate Capability ◽  
Charge Transfer Resistance ◽  
Acetylene Black ◽  
Free Standing ◽  
Transfer Resistance ◽  
Lithium Sulfur Batteries ◽  
Multi Walled Carbon Nanotubes ◽  
Lithium Sulfur

Sulfurized polyacrylonitrile (S-PAN) is one of the best materials for addressing some of the intrinsic drawbacks of lithium–sulfur batteries, such as the intrinsic insulating properties of sulfur and the shuttle phenomenon. Moreover, while S-PAN nanofiber composites are flexible, they still presents shortcomings, such as low rate capability, which is due to their semiconductor electrical conductivity. In this study, we prepared S-PAN webs with high electrical conductivity via electrospinning using conducting agents. Additionally, we analyzed the electrochemical properties of the S-PAN webs prepared using various conducting agents (acetylene black, Ketjen black, and multi-walled carbon nanotubes). The specific capacity of the S-PAN web prepared using acetylene black was 740 mAh g–1 at the charge rate of 5 C. The excellent rate capability of S-PAN prepared using acetylene black was attributed to its low electrical resistance and low charge transfer resistance.

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