scholarly journals Heat Generation in NMC622 Coin Cells during Electrochemical Cycling: Separation of Reversible and Irreversible Heat Effects

Batteries ◽  
2020 ◽  
Vol 6 (4) ◽  
pp. 55
Author(s):  
Wenjiao Zhao ◽  
Magnus Rohde ◽  
Ijaz Ul Mohsin ◽  
Carlos Ziebert ◽  
Hans J. Seifert
Keyword(s):  
Heat Effect ◽  
Electrochemical Impedance ◽  
Lithium Ion ◽  
Entropy Change ◽  
Change Measurement ◽  
Galvanostatic Intermittent Titration Technique ◽  
Lithium Ion Cell ◽  
Heat Effects ◽  
Electrochemical Cycling ◽  
Current Flows

The thermal behavior of a commercial lithium-ion cell with the cathode material LiNi0.6Mn0.2Co0.2O2 (NMC622) was investigated during the cycling process using a Tian-Calvet calorimeter (C80, SETARAM Instrumentation, France). Various current flows of 42.5, 85, and 170 mA corresponding to charging rates of 0.5, 1, and 2 C, respectively, were applied in the measurements. The corresponding heat flow rates were measured by the C80 calorimeter at 30 °C. The reversible heat effect due to the reversible electrochemical reaction was quantified by the entropy change measurement. The irreversible heat effect due to internal resistances was determined by the electrochemical impedance spectroscopy (EIS) and the galvanostatic intermittent titration technique (GITT). The results were compared with the direct measurement of the heat effect by calorimetry during electrochemical cycling.

scholarly journals Electrochemical Behavior of NH4F-Pretreated Li1.25Ni0.20Fe0.13Co0.33Mn0.33O2 Cathodes for Lithium-ion Batteries

2020 ◽  
Vol 10 (3) ◽  
pp. 1021
Author(s):  
Yonglei Zheng ◽  
Yikai Li ◽  
He Wang ◽  
Siheng Chen ◽  
Xiangxin Guo ◽  
...  
Keyword(s):  
Lithium Ion Batteries ◽  
Electrochemical Impedance ◽  
Lithium Ion ◽  
X Ray Diffraction ◽  
Capacity Retention ◽  
Hierarchical Microspheres ◽  
Electrochemical Cycling ◽  
Novel Method ◽  
Diffraction Patterns ◽  
Discharge Capacities

We report a novel method to fabricate lithium-ion batteries cathodes with the NH4F pretreatment. In this study, NH4F-pretreated Li1.25Ni0.20Fe0.13Co0.33Mn0.33O2 hollow nano-micro hierarchical microspheres were synthesized for use as cathode materials. The X-ray diffraction patterns of NH4F-pretreated Li1.25Ni0.20Co0.33Fe0.13Mn0.33O2 were analyzed with the RIETAN-FP software program, and the results showed that the samples possess a layered α-NaFeO2 structure. The effects of pretreatment with NH4F on the electrochemical performance of the pristine material were evaluated through charge/discharge cycling, the rate performance, and electrochemical impedance spectroscopy (EIS). Pretreatment with NH4F significantly improved the discharge capacities and coulombic efficiencies of Li1.25Ni0.20Co0.33Fe0.13Mn0.33O2 in the first cycle and during subsequent electrochemical cycling. The sample pretreated with an appropriate amount of NH4F (NFCM 90) showed the highest discharge capacity (209.1 mA h g−1) and capacity retention (85.2% for 50 cycles at 0.1 C). The EIS results showed that the resistance of the NFCM 90 sample (76.32 Ω) is lower than that of the pristine one (206.2 Ω).

A study on the impact of lithium-ion cell relaxation on electrochemical impedance spectroscopy

2015 ◽  
Vol 280 ◽  
pp. 74-80 ◽  
Author(s):  
Anup Barai ◽  
Gael H. Chouchelamane ◽  
Yue Guo ◽  
Andrew McGordon ◽  
Paul Jennings
Keyword(s):  
Electrochemical Impedance Spectroscopy ◽  
Impedance Spectroscopy ◽  
Electrochemical Impedance ◽  
Lithium Ion ◽  
Lithium Ion Cell ◽  
The Impact

scholarly journals The Electrochemical Stability of Starch Carbon as an Important Property in the Construction of a Lithium-Ion Cell

Entropy ◽  
2021 ◽  
Vol 23 (7) ◽  
pp. 861
Author(s):  
Beata Kurc ◽  
Marita Pigłowska ◽  
Łukasz Rymaniak
Keyword(s):  
Activation Energy ◽  
Electrochemical Impedance ◽  
Lithium Ion ◽  
Interface Layer ◽  
Cell System ◽  
Electrochemical Stability ◽  
Lithium Ion Cell ◽  
Cell Element ◽  
Different Temperatures ◽  
Anode Electrode

This paper shows use of starch-based carbon (CSC) and graphene as the anode electrode for lithium-ion cell. To describe electrochemical stability of the half-cell system and kinetic parameters of charging process in different temperatures, electrochemical impedance spectroscopy (EIS) measurement was adopted. It has been shown that smaller resistances are observed for CSC. Additionally, Bode plots show high electrochemical stability at higher temperatures. The activation energy for the SEI (solid–electrolyte interface) layer, charge transfer, and electrolyte were in the ranges of 24.06–25.33, 68.18–118.55, and 13.84–15.22 kJ mol−1, respectively. Moreover, the activation energy of most processes is smaller for CSC, which means that this electrode could serve as an eco-friendly biodegradable lithium-ion cell element.

scholarly journals Hydrothermally Synthesized Nanostructured LiMnxFe1-xPO4 (x = 0-0.3) Cathode Materials With Enhanced Properties for Lithium-Ion Batteries

2021 ◽  
Author(s):  
Dung V. Trinh ◽  
Mai T. T. Nguyen ◽  
Hue T. M. Dang ◽  
Dung T. Dang ◽  
Hang T. T. Le ◽  
...  
Keyword(s):  
Cathode Materials ◽  
Electrochemical Impedance ◽  
Lithium Ion ◽  
Slight Reduction ◽  
X Ray Diffraction ◽  
Hydrothermal Route ◽  
X Ray ◽  
Capacity Loss ◽  
Galvanostatic Intermittent Titration Technique ◽  
Mn Doped

Abstract Nanostructured cathode materials based on Mn-doped olivine LiMnxFe1-xPO4 (x = 0, 0.1, 0.2, and 0.3) were successfully synthesized via a hydrothermal route. X-ray diffraction (XRD), energy-dispersive X-ray spectroscopy (EDS), field-emission scanning electron microscopy (SEM), and Raman spectroscopy indicated that the synthesized samples possessed a sphere-like nanostructure and a relatively homogeneous size distribution in the range of 100 - 200 nm. Electrochemical experiments and analysis showed that the Mn doping increased the redox potential and boosted the capacity. While the undoped olivine (LiFePO4) had a capacity of 169 mAh g-1 with a slight reduction (10%) in the initial capacity after 50 cycles (150 mAh g-1), the Mn-doped olivine samples (LiMnxFe1-xPO4) demonstrated reliable cycling tests with negligible capacity loss, reaching 151, 147, and 157 mAh g-1 for x = 0.1, 0.2, and 0.3, respectively. The results from electrochemical impedance spectroscopy (EIS) accompanied by the galvanostatic intermittent titration technique (GITT) confirmed that the Mn substitution for Fe promoted the charge transfer process and hence the rapid Li transport. These findings indicate that the LiMnxFe1-xPO4 nanostructures are promising cathode materials for lithium ion battery applications.

Electrochemical impedance study of LiCoO2 cathode reactions in a lithium ion cell incorporating a reference electrode

2015 ◽  
Vol 19 (4) ◽  
pp. 1203-1210 ◽  
Author(s):  
Omar Samuel Mendoza-Hernandez ◽  
Hiroaki Ishikawa ◽  
Yuuki Nishikawa ◽  
Yuki Maruyama ◽  
Yoshitsugu Sone ◽  
...  
Keyword(s):  
Electrochemical Impedance ◽  
Reference Electrode ◽  
Lithium Ion ◽  
Impedance Study ◽  
Lithium Ion Cell ◽  
Licoo2 Cathode

scholarly journals Hydrothermally synthesized nanostructured LiMnxFe1−xPO4 (x = 0–0.3) cathode materials with enhanced properties for lithium-ion batteries

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Dung V. Trinh ◽  
Mai T. T. Nguyen ◽  
Hue T. M. Dang ◽  
Dung T. Dang ◽  
Hang T. T. Le ◽  
...  
Keyword(s):  
Cathode Materials ◽  
Electrochemical Impedance ◽  
Lithium Ion ◽  
Slight Reduction ◽  
Hydrothermal Route ◽  
X Ray ◽  
Capacity Loss ◽  
Galvanostatic Intermittent Titration Technique ◽  
Mn Doped ◽  
Titration Technique

AbstractNanostructured cathode materials based on Mn-doped olivine LiMnxFe1−xPO4 (x = 0, 0.1, 0.2, and 0.3) were successfully synthesized via a hydrothermal route. The field-emission scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDS) analyzed results indicated that the synthesized LiMnxFe1−xPO4 (x = 0, 0.1, 0.2, and 0.3) samples possessed a sphere-like nanostructure and a relatively homogeneous size distribution in the range of 100–200 nm. Electrochemical experiments and analysis showed that the Mn doping increased the redox potential and boosted the capacity. While the undoped olivine (LiFePO4) had a capacity of 169 mAh g−1 with a slight reduction (10%) in the initial capacity after 50 cycles (150 mAh g−1), the Mn-doped olivine samples (LiMnxFe1−xPO4) demonstrated reliable cycling tests with negligible capacity loss, reaching 151, 147, and 157 mAh g−1 for x = 0.1, 0.2, and 0.3, respectively. The results from electrochemical impedance spectroscopy (EIS) accompanied by the galvanostatic intermittent titration technique (GITT) have resulted that the Mn substitution for Fe promoted the charge transfer process and hence the rapid Li transport. These findings indicate that the LiMnxFe1−xPO4 nanostructures are promising cathode materials for lithium ion battery applications.

scholarly journals Simplified Pouch Cell Method for 3-electrode Re-testing of Harvested Double-sided Electrodes from Commercial Lithium-ion Batteries

2020 ◽  
pp. 1-19
Author(s):  
Martin A. Dann ◽  
Michael P. Hladky ◽  
Partha P. Mukherjee ◽  
Mukul Parmananda ◽  
Hanwei Zhou ◽  
...  
Keyword(s):  
Lithium Ion Batteries ◽  
Cell Function ◽  
Ethylene Carbonate ◽  
Lithium Ion ◽  
Potential Range ◽  
Counter Electrodes ◽  
Cell Method ◽  
Lithium Ion Cell ◽  
Electrochemical Cycling ◽  
Electrical Connections

Abstract A pouch cell method for retesting double-sided electrodes harvested from commercial lithium-ion batteries in a 3-electrode cell arrangement has been developed. By relying on pressure from restraint plates to make tab electrical connections, this method (1) requires no welding, (2) does not require a dry room, (3) does not require precision sealing equipment inside of an inert-gas glove box, and (4) does not require removal of composite material off of one side of the electrode which may compromise the composite to be tested on the other side. Lithium chips pressed onto copper mesh serve as the reference and counter electrodes and the electrolyte used was 1.0M LiPF6 1:1 ethylene carbonate (EC):Diethyl carbonate (DEC) v/v. Electrochemical cycling of electrodes from a commercial 3.6 Ah 18650 lithium-ion cell demonstrated cell function and showed stable capacity and potential charge/discharge profiles after 2 cycles for the cathode and 4 cycles for the anode. The areal capacity of the anode and cathode was determined to be 5.50 ± 0.31 and 5.50 ± 0.30 mAh/cm2, respectively, based on a potential range of 0.005-1.5 V vs. Li/Li+ for the anode and 3.0-4.25 V vs. Li/Li+ for the cathode. High frequency, 500 kHz impedance measurements of the anode and cathode cells shows a real impedance of 1.55 Ohms and 2.17 Ohms, respectively, which is similar to prior studies on pouch cells with continuous tabs of similar capacity.

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