α -Fe2 O3 /TiO2 Hybrids with Tunable Morphologies as Efficient Photocatalysts and Positive Electrodes for Supercapacitors

2018 ◽  
Vol 3 (11) ◽  
pp. 3284-3294 ◽  
Author(s):  
Mayukh Chakravarty ◽  
Anupam Das ◽  
Chitralee Sarma ◽  
Poulomi Roy
Keyword(s):  
Positive Electrodes ◽  
Electrodes For Supercapacitors

Controllable synthesis of hierarchical NiCo2S4@Ni3S2 core–shell nanotube arrays with excellent electrochemical performance for aqueous asymmetric supercapacitors

RSC Advances ◽  
2016 ◽  
Vol 6 (99) ◽  
pp. 97352-97362 ◽  
Author(s):  
Taobin He ◽  
Senlin Wang ◽  
Fengxia Lu ◽  
Mucan Zhang ◽  
Xiao Zhang ◽  
...  
Keyword(s):  
Electrochemical Performance ◽  
Hydrothermal Reaction ◽  
Nanotube Arrays ◽  
Core Shell ◽  
Controllable Synthesis ◽  
Ni Foam ◽  
Asymmetric Supercapacitors ◽  
Positive Electrodes ◽  
Excellent Electrochemical Performance ◽  
Electrodes For Supercapacitors

Unique NiCo2S4@Ni3S2 core–shell nanotube arrays with a hierarchical structure, as promising positive electrodes for supercapacitors, were designed and synthesized on the surface of Ni foam via a hydrothermal reaction and electrodeposition method.

Capacitive matching of pore size and ion size in the negative and positive electrodes for supercapacitors

2011 ◽  
Vol 56 (25) ◽  
pp. 9248-9256 ◽  
Author(s):  
Gangwei Sun ◽  
Wenhua Song ◽  
Xiaojun Liu ◽  
Donghui Long ◽  
Wenming Qiao ◽  
...  
Keyword(s):  
Pore Size ◽  
Positive Electrodes ◽  
Ion Size ◽  
Electrodes For Supercapacitors

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>

Cellulose Separators with Integrated Carbon Nanotube Interlayers for Lithium-Sulfur Batteries: An Investigation into the Complex Interplay Between Cell Components

2019 ◽  
Author(s):  
Yu-Chuan Chien ◽  
Ruijun Pan ◽  
Ming-Tao Lee ◽  
Leif Nyholm ◽  
Daniel Brandell ◽  
...  
Keyword(s):  
Coulombic Efficiency ◽  
Solid Electrolyte Interphase ◽  
Holistic Approach ◽  
Cycle Life ◽  
Complex Interplay ◽  
Positive Electrodes ◽  
Lithium Sulfur Batteries ◽  
Cell Components ◽  
Redox Shuttle ◽  
Lithium Sulfur

This work aims to address two major roadblocks in the development of lithium-sulfur (Li-S) batteries: the inefficient deposition of Li on the metallic Li electrode and the parasitic "polysulfide redox shuttle". These roadblocks are here approached, respectively, by the combination of a cellulose separator with a cathode-facing conductive porous carbon interlayer, based on their previously reported individual benefits. The cellulose separator increases cycle life by 33%, and the interlayer by a further 25%, in test cells with positive electrodes with practically relevant specifications and a relatively low electrolyte/sulfur (E/S) ratio. Despite the prolonged cycle life, the combination of the interlayer and cellulose separator increases the polysulfide shuttle current, leading to reduced Coulombic efficiency. Based on XPS analyses, the latter is ascribed to a change in the composition of the solid electrolyte interphase (SEI) on Li. Meanwhile, electrolyte decomposition is found to be slower in cells with cellulose-based separators, which explains their longer cycle life. These counterintuitive observations demonstrate the complicated interactions between the cell components in the Li-S system and how strategies aiming to mitigate one unwanted process may exacerbate another. This study demonstrates the value of a holistic approach to the development of Li-S chemistry.<br>

Highly thermally conductive graphene-based electrodes for supercapacitors with excellent heat dissipation ability

2017 ◽  
Vol 1 (10) ◽  
pp. 2145-2154 ◽  
Author(s):  
Bo Zhao ◽  
Xian-Zhu Fu ◽  
Rong Sun ◽  
Ching-Ping Wong
Keyword(s):  
Heat Dissipation ◽  
Cycling Performance ◽  
Thermally Conductive ◽  
Rate Capacity ◽  
Electrodes For Supercapacitors

The highly thermally conductive graphene-based electrodes for supercapacitors exhibit great heat dissipation ability as well as excellent cycling performance and rate capacity.

scholarly journals The Equilibrium Phase Formation and Thermodynamic Properties of Functional Tellurides in the Ag–Fe–Ge–Te System

Energies ◽  
2021 ◽  
Vol 14 (5) ◽  
pp. 1314
Author(s):  
Mykola Moroz ◽  
Fiseha Tesfaye ◽  
Pavlo Demchenko ◽  
Myroslava Prokhorenko ◽  
Nataliya Yarema ◽  
...  
Keyword(s):  
Electromotive Force ◽  
Equilibrium Phase ◽  
Stoichiometric Composition ◽  
Negative Electrode ◽  
Electrochemical Cells ◽  
Thermodynamic Quantities ◽  
Positive Electrodes ◽  
Gibbs Energies ◽  
Buffer Region ◽  
First Time

Equilibrium phase formations below 600 K in the parts Ag2Te–FeTe2–F1.12Te–Ag2Te and Ag8GeTe6–GeTe–FeTe2–AgFeTe2–Ag8GeTe6 of the Fe–Ag–Ge–Te system were established by the electromotive force (EMF) method. The positions of 3- and 4-phase regions relative to the composition of silver were applied to express the potential reactions involving the AgFeTe2, Ag2FeTe2, and Ag2FeGeTe4 compounds. The equilibrium synthesis of the set of phases was performed inside positive electrodes (PE) of the electrochemical cells: (−)Graphite ‖LE‖ Fast Ag+ conducting solid-electrolyte ‖R[Ag+]‖PE‖ Graphite(+), where LE is the left (negative) electrode, and R[Ag+] is the buffer region for the diffusion of Ag+ ions into the PE. From the observed results, thermodynamic quantities of AgFeTe2, Ag2FeTe2, and Ag2FeGeTe4 were experimentally determined for the first time. The reliability of the division of the Ag2Te–FeTe2–F1.12Te–Ag2Te and Ag8GeTe6–GeTe–FeTe2–AgFeTe2–Ag8GeTe6 phase regions was confirmed by the calculated thermodynamic quantities of AgFeTe2, Ag2FeTe2, and Ag2FeGeTe4 in equilibrium with phases in the adjacent phase regions. Particularly, the calculated Gibbs energies of Ag2FeGeTe4 in two different adjacent 4-phase regions are consistent, which also indicates that it has stoichiometric composition.

Alginate Biopolymer Effect on the Electrodeposition of Manganese Dioxide on Electrodes for Supercapacitors

2021 ◽  
Author(s):  
Kethaki Wickramaarachchi ◽  
Manickam Minakshi Sundaram ◽  
David J. Henry ◽  
Xiangpeng Gao
Keyword(s):  
Manganese Dioxide ◽  
Electrodes For Supercapacitors
Sign in / Sign up

Export Citation Format

Share Document