Carbon Transition‐metal Oxide Electrodes: Understanding the Role of Surface Engineering for High Energy Density Supercapacitors

2020 ◽  
Vol 15 (11) ◽  
pp. 1628-1647 ◽  
Author(s):  
Gracita M. Tomboc ◽  
Bekelcha Tesfaye Gadisa ◽  
Minki Jun ◽  
Nitin K. Chaudhari ◽  
Hern Kim ◽  
...  
Keyword(s):  
Energy Density ◽  
Transition Metal ◽  
Metal Oxide ◽  
Surface Engineering ◽  
Transition Metal Oxide ◽  
High Energy ◽  
High Energy Density ◽  
Oxide Electrodes

scholarly journals Oxygen Redox Activity in Cathodes – a Common Phenomenon Calling for Density-Based Descriptors

2020 ◽  
Author(s):  
Daniel Koch ◽  
Sergei Manzhos
Keyword(s):  
Transition Metal ◽  
Metal Oxide ◽  
Charge Density ◽  
Density Of States ◽  
Transition Metal Oxide ◽  
High Energy ◽  
High Energy Density ◽  
Redox Activity ◽  
Spherical Approximation ◽  
Redox Active

Lithium-excess transition metal oxide materials are promising cathode candidates for future secondary batteries due to their relatively high energy density, which is commonly related to redox-active oxygen centers. First-principle computations are crucial for the understanding of the underlying redox mechanism in these compounds, with plane-wave density functional theory being the most frequently used setup. An important tool for the assignment of the redox-active species is the projected density of states, although the atomic contributions postulated this way do not strictly correspond to any observable physical quantity. By directly analyzing the computed real-space charge density changes, on the other hand, oxygen redox activity can be found to be substantial in most transition metal oxide compounds, although a projection onto atomic states would suggest otherwise. This can be linked to the shortcomings of the commonly employed spherical approximation for ions in crystalline compounds used to compute the projected density of states, which fails to describe the charge density topology in covalent transition metal oxides and leads to a qualitatively different picture from a charge density-based approach, specifically, the underrepresentation of oxygen contributions and exaggeration of transition metal contributions to the density of states The density based approach, due to the non-spherical nature of Bader domains, is more apt to properly describe oxygen redox contributions. This raises the question how meaningful the descriptors of oxygen redox activity are and how it should be acknowledged for transition metal oxide compounds in general.

Mixed solvent exfoliated transition metal oxides nanosheets based flexible solid state supercapacitor devices endowed with high energy density

2019 ◽  
Vol 43 (31) ◽  
pp. 12385-12395 ◽  
Author(s):  
Shibsankar Dutta ◽  
Shreyasi Pal ◽  
Sukanta De
Keyword(s):  
Solid State ◽  
Energy Density ◽  
Transition Metal ◽  
Metal Oxide ◽  
Metal Oxides ◽  
Specific Capacitance ◽  
Transition Metal Oxides ◽  
Mixed Solvent ◽  
High Energy ◽  
High Energy Density

Mixed solvent exfoliated transition metal oxide nanosheet/SWCNT composite based flexible supercapacitors demonstrate large specific capacitance and high energy density.

scholarly journals Oxygen Redox Activity in Cathodes – a Common Phenomenon Calling for Density-Based Descriptors

2020 ◽  
Author(s):  
Daniel Koch ◽  
Sergei Manzhos
Keyword(s):  
Transition Metal ◽  
Metal Oxide ◽  
Charge Density ◽  
Density Of States ◽  
Transition Metal Oxide ◽  
High Energy ◽  
High Energy Density ◽  
Redox Activity ◽  
Spherical Approximation ◽  
Redox Active

Lithium-excess transition metal oxide materials are promising cathode candidates for future secondary batteries due to their relatively high energy density, which is commonly related to redox-active oxygen centers. First-principle computations are crucial for the understanding of the underlying redox mechanism in these compounds, with plane-wave density functional theory being the most frequently used setup. An important tool for the assignment of the redox-active species is the projected density of states, although the atomic contributions postulated this way do not strictly correspond to any observable physical quantity. By directly analyzing the computed real-space charge density changes, on the other hand, oxygen redox activity can be found to be substantial in most transition metal oxide compounds, although a projection onto atomic states would suggest otherwise. This can be linked to the shortcomings of the commonly employed spherical approximation for ions in crystalline compounds used to compute the projected density of states, which fails to describe the charge density topology in covalent transition metal oxides and leads to a qualitatively different picture from a charge density-based approach, specifically, the underrepresentation of oxygen contributions and exaggeration of transition metal contributions to the density of states The density based approach, due to the non-spherical nature of Bader domains, is more apt to properly describe oxygen redox contributions. This raises the question how meaningful the descriptors of oxygen redox activity are and how it should be acknowledged for transition metal oxide compounds in general.

New Transition Metal Oxide Electrodes for Lithium Batteries

2000 ◽  
pp. 241-261 ◽  
Author(s):  
A. Gal La Salle ◽  
A. Verbaere ◽  
Y. Piffard ◽  
D. Guyomard
Keyword(s):  
Transition Metal ◽  
Metal Oxide ◽  
Lithium Batteries ◽  
Transition Metal Oxide ◽  
Oxide Electrodes
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