Understanding the electrochemical potential and diffusivity of MnO/C nanocomposites at various charge/discharge states

2019 ◽  
Vol 7 (13) ◽  
pp. 7831-7842 ◽  
Author(s):  
Chaofeng Liu ◽  
Haoyu Fu ◽  
Yanyan Pei ◽  
Jiandong Wu ◽  
Vivek Pisharodi ◽  
...  
Keyword(s):  
Electrochemical Impedance Spectroscopy ◽  
Impedance Spectroscopy ◽  
Crystal Field ◽  
Electrochemical Impedance ◽  
Electrochemical Potential ◽  
Field Analysis ◽  
Kinetics Of ◽  
Charge Discharge

Electrochemical potential and lithiation kinetics of MnO/C nanocomposites were investigated by crystal field analysis and electrochemical impedance spectroscopy.

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.

Carbon Nanotubes on the Performance of Al3+ Doped α-Nickel Hydroxide

2011 ◽  
Vol 287-290 ◽  
pp. 1416-1419
Author(s):  
Chang Jiu Liu ◽  
Pei Pei Li ◽  
Liang Hua Huang
Keyword(s):  
Carbon Nanotubes ◽  
Electrochemical Impedance Spectroscopy ◽  
Impedance Spectroscopy ◽  
Electrochemical Performance ◽  
Nickel Hydroxide ◽  
Electrochemical Impedance ◽  
Electrochemical Reaction ◽  
Cycling Stability ◽  
Specific Discharge ◽  
Charge Discharge

The effect of carbon nanotubes (CNTs) addition on the electrochemical performance of Al doped α-nickel hydroxide is studied. The microstructure and electrochemical performance of the prepared samples are characterized by XRD,SEM, electrochemical impedance spectroscopy, charge-discharge at different rate, and Charge-discharge cycling stability tests. The results show that the addition of CNTs could decrease the electrochemical reaction impedance dramatically, increase the specific discharge capacity at higher rate, and improve the Charge-discharge cycling stability reversibility.

Kinetics of Passive Film Growth on 304 Stainless Steel in H2SO4 Pickling Solution under Chemical Oxidation

CORROSION ◽  
10.5006/2680 ◽  
2018 ◽  
Vol 74 (6) ◽  
pp. 705-714 ◽  
Author(s):  
Yingying Yue ◽  
Chengjun Liu ◽  
Edouard Asselin ◽  
Peiyang Shi ◽  
Maofa Jiang
Keyword(s):  
Stainless Steel ◽  
Electrochemical Impedance Spectroscopy ◽  
Impedance Spectroscopy ◽  
Passive Film ◽  
Polarization Resistance ◽  
Film Growth ◽  
Electrochemical Impedance ◽  
304 Stainless Steel ◽  
Passive Film Growth ◽  
Kinetics Of

H2SO4-H2O2 mixtures are a promising and environmentally friendly passivation medium for the stainless-steel pickling process. The corrosion behavior of stainless steel is highly dependent on the kinetics of passive film growth. Long-term electrochemical measurements, including polarization resistance, open circuit potential (OCP), and electrochemical impedance spectroscopy (EIS) measurements were performed to investigate the evolution of the passive state of 304 stainless steel. According to the OCP results, an active-passive transition takes place in 10 ks in 0.5 M H2SO4 solution containing 0.005 M to 0.3 M H2O2. Polarization resistance results indicate that the passive film thickness keeps growing after OCP stabilization in the presence of H2O2. Electrochemical impedance spectroscopy (EIS) results confirmed that the growth of the passive film in H2SO4-H2O2 solutions takes about 9 h. Additionally, according to the Point Defect Model (PDM) and Mott–Schottky analysis, the semiconductor properties of the passive film on 304 stainless steel in H2SO4-H2O2 solution were studied. The results indicate that the passive film is an n-type semiconductor. The donor density is in the range of 1.6 × 10−21 cm−3 to 24 and decreases exponentially with increasing film formation potential (this potential coincides with the final OCP in the corresponding H2SO4-H2O2 solutions). By postulating that most donors are oxygen vacancies, the point defect properties including diffusivity and electrical field strength are obtained.

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