scholarly journals The effect of electrochemical cycling on the strength of LiCoO2

2018 ◽  
Vol 102 (1) ◽  
pp. 372-381 ◽  
Author(s):  
Lin Feng ◽  
Xuefeng Lu ◽  
Tingting Zhao ◽  
Shen Dillon
Keyword(s):  
Electrochemical Cycling

Anionic and Cationic Redox Processes in β-Li2IrO3 and Their Structural Implications on Electrochemical Cycling in Li-Ion Cell

2019 ◽  
Author(s):  
Paul Pearce ◽  
Gaurav Assat ◽  
Antonella Iadecola ◽  
François Fauth ◽  
Rémi Dedryvère ◽  
...  
Keyword(s):  
Analytical Techniques ◽  
Charge Compensation ◽  
Coupling Mechanism ◽  
Redox Processes ◽  
Positive Electrodes ◽  
X Ray ◽  
Electrochemical Cycling ◽  
Li Ion ◽  
Electrochemical Instability ◽  
High Degree

The recent discovery of anionic redox as a means to increase the energy density of transition metal oxide positive electrodes is now a well established approach in the Li-ion battery field. However, the science behind this new phenomenon pertaining to various Li-rich materials is still debated. Thus, it is of paramount importance to develop a robust set of analytical techniques to address this issue. Herein, we use a suite of synchrotron-based X-ray spectroscopies as well as diffraction techniques to thoroughly characterize the different redox processes taking place in a model Li-rich compound, the tridimentional hyperhoneycomb β-Li2IrO3. We clearly establish that the reversible removal of Li+ from this compound is associated to a previously described reductive coupling mechanism and the formation of the M-(O-O) and M-(O-O)* states. We further show that the respective contributions to these states determine the spectroscopic response for both Ir L3-edge X-ray absorption spectroscopy (XAS) and X-ray photoemissions spectroscopy (XPS). Although the high covalency and the robust tridimentional structure of this compound enable a high degree of reversibile delithiation, we found that pushing the limits of this charge compensation mechanism has significant effects on the local as well as average structure, leading to electrochemical instability over cycling and voltage decay. Overall, this work highlights the practical limits to which anionic redox can be exploited and sheds some light on the nature of the oxidized species formed in certain lithium-rich compounds.<br>

Anionic and Cationic Redox Processes in β-Li2IrO3 and Their Structural Implications on Electrochemical Cycling in Li-Ion Cell

2019 ◽  
Author(s):  
Paul Pearce ◽  
Gaurav Assat ◽  
Antonella Iadecola ◽  
François Fauth ◽  
Rémi Dedryvère ◽  
...  
Keyword(s):  
Analytical Techniques ◽  
Charge Compensation ◽  
Coupling Mechanism ◽  
Redox Processes ◽  
Positive Electrodes ◽  
X Ray ◽  
Electrochemical Cycling ◽  
Li Ion ◽  
Electrochemical Instability ◽  
High Degree

The recent discovery of anionic redox as a means to increase the energy density of transition metal oxide positive electrodes is now a well established approach in the Li-ion battery field. However, the science behind this new phenomenon pertaining to various Li-rich materials is still debated. Thus, it is of paramount importance to develop a robust set of analytical techniques to address this issue. Herein, we use a suite of synchrotron-based X-ray spectroscopies as well as diffraction techniques to thoroughly characterize the different redox processes taking place in a model Li-rich compound, the tridimentional hyperhoneycomb β-Li2IrO3. We clearly establish that the reversible removal of Li+ from this compound is associated to a previously described reductive coupling mechanism and the formation of the M-(O-O) and M-(O-O)* states. We further show that the respective contributions to these states determine the spectroscopic response for both Ir L3-edge X-ray absorption spectroscopy (XAS) and X-ray photoemissions spectroscopy (XPS). Although the high covalency and the robust tridimentional structure of this compound enable a high degree of reversibile delithiation, we found that pushing the limits of this charge compensation mechanism has significant effects on the local as well as average structure, leading to electrochemical instability over cycling and voltage decay. Overall, this work highlights the practical limits to which anionic redox can be exploited and sheds some light on the nature of the oxidized species formed in certain lithium-rich compounds.<br>

scholarly journals In situ XRD and operando spectra-electrochemical investigation of tetragonal WO3-x nanowire networks for electrochromic supercapacitors

2021 ◽  
Vol 13 (1) ◽  
Author(s):  
Shen Wang ◽  
Hongbo Xu ◽  
Tingting Hao ◽  
Peiyuan Wang ◽  
Xiang Zhang ◽  
...  
Keyword(s):  
Reaction Mechanism ◽  
Electronic Device ◽  
High Capacity ◽  
Optical Modulation ◽  
Function Evaluation ◽  
Dual Function ◽  
Electrochemical Performances ◽  
Electrochemical Cycling ◽  
Nanowire Networks

AbstractElectrochromic supercapacitors (ESCs) are appealing for smart electronic device applications due to their advantages of dual-function integration. Unfortunately, the synchronous dual-function evaluation and the essential reaction mechanism are ambiguous. Herein, we constructed a 3D WO3-x nanowire networks/fluorine-doped tin oxide (WO3-x NWNs/FTO) bifunctional electrode for ESCs by a solvothermal self-crystal seeding method. The synchronous correspondence relationship between the optical and electrochemical performances of the WO3-x NWNs/FTO electrode was explored using an operando spectra-electrochemical characterization method. It reveals an excellent areal capacity of 57.57 mF cm−2 with a high corresponding optical modulation (ΔT) of 85.05% and high optical-electrochemical cycling stability. Furthermore, the synergistic reaction mechanism between the Al3+ ion intercalation behavior and the surface pseudocapacitance reaction during electrochemical cycling is revealed utilizing in situ X-ray diffraction. Based on these results, an ESC device was constructed by pairing WO3-x/FTO as the cathode with V2O5 nanoflowers/FTO (V2O5 NFs/FTO) as the anode, which simultaneously deliver high capacity and large optical modulation. Moreover, the energy storage level of the ESC device could be visually monitored by rapid and reversible color transitions in real time. This work provides a promising pathway to developing multi-functional integrated smart supercapacitors.

The AMPIX electrochemical cell: a versatile apparatus forin situX-ray scattering and spectroscopic measurements

2012 ◽  
Vol 45 (6) ◽  
pp. 1261-1269 ◽  
Author(s):  
Olaf J. Borkiewicz ◽  
Badri Shyam ◽  
Kamila M. Wiaderek ◽  
Charles Kurtz ◽  
Peter J. Chupas ◽  
...  
Keyword(s):  
Electrochemical Cell ◽  
Function Analysis ◽  
Kinetic Studies ◽  
Spectroscopic Measurements ◽  
Battery Materials ◽  
X Ray ◽  
Complex Processes ◽  
Electrochemical Cycling ◽  
Ray Scattering

This article presents a versatile easy-to-use electrochemical cell suitable forin operando,in situmeasurements of battery materials during electrochemical cycling using a variety of X-ray techniques. Argonne's multi-purposein situX-ray (AMPIX) cell provides reliable electrochemical cycling over extended periods owing to the uniform stack pressure applied by rigid X-ray windows and the formation of a high-fidelity hermetic seal. The suitability of the AMPIX cell for a broad range of synchrotron-based X-ray scattering and spectroscopic measurements has been demonstrated with studies at eight Advanced Photon Source beamlines to date. Compatible techniques include pair distribution function analysis, high-resolution powder diffraction, small-angle scattering and X-ray absorption spectroscopy. These techniques probe a broad range of electronic, structural and morphological features relevant to battery materials. The AMPIX cell enables experiments providing greater insight into the complex processes that occur in operating batteries by allowing the electrochemical reactions to be probed at fine reaction intervals with greater consistency (within the charge–discharge cycle and between different methodologies) with potential for new time-dependent kinetic studies or studies of transient species. Representative X-ray and electrochemical data to demonstrate the functionality of the AMPIX cell are presented.

Real-time monitoring of stress development during electrochemical cycling of electrode materials for Li-ion batteries: overview and perspectives

2019 ◽  
Vol 7 (41) ◽  
pp. 23679-23726 ◽  
Author(s):  
Manoj K. Jangid ◽  
Amartya Mukhopadhyay
Keyword(s):  
Real Time ◽  
Electrode Materials ◽  
Electrochemical Potential ◽  
Li Ion Batteries ◽  
Stress Development ◽  
Electrochemical Cycling ◽  
Li Ion ◽  
Real Time Information ◽  
Time Information

Monitoring stress development in electrodes in-situ provides a host of real-time information on electro-chemo-mechanical aspects as functions of SOC and electrochemical potential.

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.

Cu2O Nanoparticles and Multi-Branched Nanowires as Anodes for Lithium-Ion Batteries

NANO ◽  
2018 ◽  
Vol 13 (09) ◽  
pp. 1850103 ◽  
Author(s):  
Xu Chen ◽  
Chunxin Yu ◽  
Xiaojiao Guo ◽  
Qinsong Bi ◽  
Muhammad Sajjad ◽  
...  
Keyword(s):  
Lithium Ion Batteries ◽  
Anode Materials ◽  
Hydrothermal Process ◽  
Specific Capacity ◽  
Lithium Ion ◽  
Discharge Process ◽  
Electrochemical Cycling ◽  
One Step ◽  
Cu2o Nanoparticles ◽  
Enhanced Electrochemical Performance

Novelty Cu2O multi-branched nanowires and nanoparticles with size ranging from [Formula: see text]15[Formula: see text]nm to [Formula: see text]60[Formula: see text]nm have been synthesized by one-step hydrothermal process. These Cu2O nanostructures when used as anode materials for lithium-ion batteries exhibit the excellent electrochemical cycling stability and reduced polarization during the repeated charge/discharge process. The specific capacity of the Cu2O nanoparticles, multi-branched nanowires and microscale are maintained at 201.2[Formula: see text]mAh/g, 259.6[Formula: see text]mAh/g and 127.4[Formula: see text]mAh/g, respectively, under the current density of 0.1[Formula: see text]A/g after 50 cycles. The enhanced electrochemical performance of the Cu2O nanostructures compared with microscale counterpart can be attributed to the larger contact area between active Cu2O nanostructures/electrolyte interface, shorter diffusion length of Li[Formula: see text] within nanostructures and the improved stress release upon lithiation/delithiation.

Sers of H2O, pyridine and halides adsorbed on Ag electrodes during electrochemical cycling

1983 ◽  
Vol 150 (1-2) ◽  
pp. 389-398 ◽  
Author(s):  
J.F. Owen ◽  
T.T. Chen ◽  
R.K. Chang ◽  
B.L. Laube
Keyword(s):  
Ag Electrodes ◽  
Electrochemical Cycling
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