scholarly journals An Amazingly Simple, Fast and Green Synthesis Route to Polyaniline Nanofibers for Efficient Energy Storage

Polymers ◽  
2020 ◽  
Vol 12 (10) ◽  
pp. 2212
Author(s):  
Sami ur Rahman ◽  
Philipp Röse ◽  
Anwar ul Haq Ali Shah ◽  
Ulrike Krewer ◽  
Salma Bilal
Keyword(s):  
Coulombic Efficiency ◽  
Rate Capability ◽  
High Specific Capacitance ◽  
Charge Transfer Resistance ◽  
Toxic Chemicals ◽  
Transfer Resistance ◽  
Synthesis Time ◽  
Supercapacitor Performance ◽  
Solution Resistance ◽  
Charge Discharge

The major drawbacks of the conventional methods for preparing polyaniline (PANI) are the large consumptions of toxic chemicals and long process durations. This paper presents a remarkably simple and green route for the chemical oxidative synthesis of PANI nanofibers, utilizing sodium phytate as a novel and environmentally friendly plant derived dopant. The process shows a remarkable reduction in the synthesis time and usage of toxic chemicals with good dispersibility and exceedingly high conductivity up to 10 S cm−1 of the resulting PANI at the same time. A detailed characterization of the PANI samples has been made showing excellent relationships between their structure and properties. Particularly, the electrochemical properties of the synthesized PANI as electrode material for supercapacitors were analyzed. The PANI sample, synthesized at pre-optimized conditions, exhibited impressive supercapacitor performance having a high specific capacitance (Csp) (832.5 Fg−1 and 528 Fg−1 at 1 Ag−1 and 40 Ag−1, respectively) as calculated from galvanostatic charge/discharge (GCD) curves. A good rate capability with a capacitance retention of 67.6% of its initial value was observed. The quite low solution resistance (Rs) value of 281.0 × 10−3 Ohm and charge transfer resistance value (Rct) of 7.44 Ohm represents the excellence of the material. Further, a retention of 95.3% in coulombic efficiency after 1000 charge discharge cycles, without showing any significant degradation of the material, was also exhibited.

Electrochemical Properties of Electrodeposited MnO2 Nanoparticles

2015 ◽  
Vol 1113 ◽  
pp. 550-553 ◽  
Author(s):  
Gomaa Abdelgawad Mohammed Ali ◽  
Mashitah M. Yusoff ◽  
Kwok Feng Chong
Keyword(s):  
Electrochemical Properties ◽  
High Specific Capacitance ◽  
Xrd Analysis ◽  
Charge Transfer Resistance ◽  
Electrochemical Studies ◽  
Galvanostatic Charge ◽  
Transfer Resistance ◽  
Electrodeposited Film ◽  
Solution Resistance ◽  
Charge Discharge

The present study shows the electrodeposition of MnO2 from KMnO2 solution and its electrochemical studies. XRD analysis shows the electrodeposited MnO2 has nano-sized particle of 18 nm. The electrochemical properties have been investigated using the cyclic voltammetry, galvanostatic charge/discharge and impedance techniques. The electrodeposited MnO2 shows good electrochemical behavior with high specific capacitance value of ca. 306 F g-1. Moreover, it shows high capacitance stability of 90% over 1000 charge/discharge cycles. Impedance result shows low solution resistance and charge transfer resistance, an indication of the conductive nature for the electrodeposited film.

scholarly journals Directly Grown Multiwall Carbon Nanotube and Hydrothermal MnO2 Composite for High-Performance Supercapacitor Electrodes

Nanomaterials ◽  
2019 ◽  
Vol 9 (5) ◽  
pp. 703 ◽  
Author(s):  
Li Li ◽  
Lihui Chen ◽  
Weijin Qian ◽  
Fei Xie ◽  
Changkun Dong
Keyword(s):  
Charge Transfer ◽  
High Performance ◽  
Rate Capability ◽  
High Specific Capacitance ◽  
Charge Transfer Resistance ◽  
Multiwall Carbon Nanotube ◽  
Ni Foam ◽  
Multiwalled Carbon ◽  
Transfer Resistance ◽  
Supercapacitor Application

MnO2–MWNT–Ni foam supercapacitor electrodes were developed based on directly grown multiwalled carbon nanotubes (MWNTs) and hydrothermal MnO2 nanostructures on Ni foam substrates. The electrodes demonstrated excellent electrochemical and battery properties. The charge transfer resistance dropped 88.8% compared with the electrode without MWNTs. A high specific capacitance of 1350.42 F·g−1 was reached at the current density of 6.5 A·g−1. The electrode exhibited a superior rate capability with 92.5% retention in 25,000 cycles. Direct MWNT growth benefits the supercapacitor application for low charge transfer resistance and strong MWNT–current collector binding.

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.

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.

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.

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 Facilely Synthesized NiCo2O4/NiCo2O4 Nanofile Arrays Supported on Nickel Foam by a Hydrothermal Method and Their Excellent Performance for High-Rate Supercapacitance

Energies ◽  
2019 ◽  
Vol 12 (7) ◽  
pp. 1308 ◽  
Author(s):  
Anil Yedluri ◽  
Eswar Araveeti ◽  
Hee-Je Kim
Keyword(s):  
Electrochemical Performance ◽  
Specific Capacitance ◽  
Nickel Foam ◽  
Rate Capability ◽  
Charge Transfer Resistance ◽  
High Rate ◽  
Transfer Resistance ◽  
Electrons And Ions ◽  
Binary Metal Oxides ◽  
Hydrothermal Approach

NiCo2O4 nanoleaf arrays (NCO NLAs) and NiCo2O4/NiCO2O4 nanofile arrays (NCO/NCO NFAs) material was fabricated on flexible nickel foam (NF) using a facile hydrothermal approach. The electrochemical performance, including the specific capacitance, charge/discharge cycles, and lifecycle of the material after the hydrothermal treatment, was assessed. The morphological and structural behaviors of the NF@NCO NLAs and NF@NCO/NCO NFAs electrodes were analyzed using a range of analysis techniques. The as-obtained nanocomposite of the NF@NCO/NCO NFAs material delivered outstanding electrochemical performance, including an ultrahigh specific capacitance (Cs) of 2312 F g−1 at a current density of 2 mA cm−2, along with excellent cycling stability (98.7% capacitance retention after 5000 cycles at 5 mA cm−2). These values were higher than those of NF@NCO NLAs (Cs of 1950 F g−1 and 96.3% retention). The enhanced specific capacitance was attributed to the large electrochemical surface area, which allows for higher electrical conductivity and rapid transport between the electrons and ions as well as a much lower charge-transfer resistance and superior rate capability. These results clearly show that a combination of two types of binary metal oxides could be favorable for improving electrochemical performance and is expected to play a major role in the future development of nanofile-like composites (NF@NCO/NCO NFAs) for supercapacitor applications.

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.

scholarly journals Optimum dose of Chaetoceros for controlling methanogenesis to improve power production of microbial fuel cell

2021 ◽  
Author(s):  
P. P. Rajesh ◽  
P. Christine ◽  
M. M. Ghangrekar
Keyword(s):  
Fuel Cell ◽  
Microbial Fuel Cell ◽  
Marine Algae ◽  
Coulombic Efficiency ◽  
Charge Transfer Resistance ◽  
Optimum Dose ◽  
Anaerobic Sludge ◽  
Power Performance ◽  
Transfer Resistance ◽  
Lower Charge

Abstract The marine algae Chaetoceros contains hexadecatrienoic acid, which suppresses methanogen development and improves the coulombic efficiency (CE) of microbial fuel cell (MFC). To inhibit the methanogens, optimum concentration of marine algae should be added to the anaerobic sludge to enhance the performance of microbial fuel cell. A varying concentration of Chaetoceros ranging from 1 to 20 mg/mL was carried out for pretreatment of anaerobic mix-consortium to suppress methanogens. MFC inoculated with pretreated anaerobic sludge with 10 mg/mL Chaetoceros showed a maximum power density of 21.62 W/m3 and a maximum CE of 37.25%, which was considerably higher than the treatment with other concentrations. At 10 mg/mL concentration, Tafel analysis of anode in MFC showed a higher exchange current density of 66.35 mA/m2 and a lower charge transfer resistance of 0.97 Ω.m2, revealing higher bio-electrochemical activity. The performance of MFC improved when the concentration of Chaetoceros was increased up to 10 mg/mL, but then began to decline as the concentration increased further. Thus, the optimum dose of Chaetoceros to be added in the mix-anaerobic consortiumto optimize the power performance of MFC is determined, which can be carried out in scaled-up MFCs.

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