scholarly journals Synthesis and Performance Elucidation of Ternary O3-Na0.8Fe0.4Mn0.3Co0.2O2 Layered Positive Electrode for Sodium Ion Batteries

2021 ◽  
pp. 54-65
Author(s):  
M. Alam Khan ◽  
Sunil Singh
Keyword(s):  
Transition Metal ◽  
Substantial Reduction ◽  
Positive Electrode ◽  
Sodium Ion ◽  
Cyclic Voltammograms ◽  
Teller Distortion ◽  
Jahn Teller ◽  
And Performance ◽  
Discharge Capacities ◽  
Charge Discharge

We report here a combination of transition metal-based ternary sodium magnate layered cathodes with the compositions of Na0.8Fe0.4Mn0.3Co0.2O2, Na0.8Fe0.4Mn0.3Ni0.2O2, Na0.8Fe0.4Mn0.3V0.2O2, Na0.8Fe0.4Mn0.3Ti0.2O2, in order to elucidate the precise metal contents for the superb performing positive electrode. Based on their stoichiometry, the transition metal combination of Na0.8Fe0.4Mn0.3Co0.2O2, O3-type crystal structure with R3m space group possess superior electrochemical behavior under the test of sodium-ion battery. When the charge-discharge capacities in the range of 2.0-4.2 V at 0.1 C are measured, it shows the comparatively higher performance of the first and second charge capacities of 162 mAhg-1, 170 mAhg-1 and discharge capacities of 157 mAhg-1, 154 mAhg-1, respectively. Moreover, it was remarkable to observe that the increasing/decreasing Co constituent substantially affects the performance and stability, but using the ternary combination in cathodes, a substantial reduction of Jahn-Teller distortion and increased biphasic characteristics were observed. The as-synthesized samples were characterized by FE-SEM, XRD, charge-discharge curve, EIS and cyclic voltammograms.

Synthesis of O3-Na0.8Fe0.6Mn0.3O2 Positive Electrode and Its Application to Sodium Ion Batteries

2021 ◽  
pp. 1-15
Author(s):  
M. Alam Khan
Keyword(s):  
Substantial Reduction ◽  
Group Behavior ◽  
Teller Distortion ◽  
Space Group ◽  
High Performing ◽  
Vacancy Ordering ◽  
Jahn Teller ◽  
P Type ◽  
Jahn Teller Distortion ◽  
Discharge Capacities

Herein, we report precise variation of Fe and Mn constituent in the sodium magnate layered cathodes with the compositions of Na0.8Fe0.4Mn0.5O2, Na0.8Fe0.5Mn0.4O2, Na0.8Fe0.6Mn0.3O2, Na0.8Fe0.6Mn0.4O2, Na0.8Fe0.7Mn0.4O2, Na0.9Fe0.6Mn0.3O2 in order to attain a high performing cathode. Based on this transition metal stoichiometry, an interesting sodium magnate combination of Na0.8Fe0.6Mn0.3O2, with O3-type crystal phase, possess R3m space group along with the superior electrochemical behavior is obtained. On charge-discharge capacities in the range of 2.0-3.8 V at 0.1 C, it shows the comparatively higher performance of the first and the second charge capacity of 115 and 180 mAhg-1 and discharge capacity of 184 and 181 mAhg-1, respectively. The best sample was then compared with the closely related Na0.8Fe0.6Mn0.4O2, Na0.9Fe0.6Mn0.3O2 combination in terms of valence ratio and influence of excess sodium for the structure robustness, stability along with purity. The best sample with the composition Na0.8Fe0.6Mn0.3O2 does not show detectable impure phase while Na0.8Fe0.6Mn0.4O2 and Na0.9Fe0.6Mn0.3O2 shows a tendency of P-type (Cmca space group) behavior with 30.8% and 32.8%, respectively. The enhancement of iron constituent increases not only the performances but also the stabilization of sodium vacancy ordering and substitution of Mn with a substantial reduction of Jahn-Teller distortion, mounting biphasic characteristics and high peak intensity of 41.5 °.

scholarly journals Chemical Modulation of Local Transition Metal Environment Enables Reversible Oxygen Redox in Mn-Based Layered Cathodes

2021 ◽  
Author(s):  
Muhammad Mominur Rahman ◽  
Scott McGuigan ◽  
Shaofeng Li ◽  
Lina Gao ◽  
Dong Hou ◽  
...  
Keyword(s):  
Transition Metal ◽  
Metal Layer ◽  
Chemical Transformations ◽  
Teller Distortion ◽  
Structural Stabilization ◽  
Factors Affecting ◽  
Jahn Teller ◽  
Chemical Modulation ◽  
Jahn Teller Distortion ◽  
Layered Cathodes

<p>Oxygen redox plays a prominent role in enhancing the energy density of Mn-based layered cathodes. However, understanding the factors affecting the reversibility of oxygen redox is nontrivial due to the complicated concurrent structural and chemical transformations. Herein, we show that local Mn‒O symmetry induced structural and chemical evolutions majorly dictate the reversibility of oxygen redox of Na<sub>x</sub>Li<sub>y</sub>Mn<sub>1-y</sub>O<sub>2</sub> in Na cells. We find that Na<sub>x</sub>Li­<sub>y</sub>Mn<sub>1-y</sub>O<sub>2</sub> with Jahn-Teller distorted MnO<sub>6</sub> octahedra undergoes severe Mn dissolution during cycling, which destabilizes the transition metal layer resulting in poor Li retention and irreversible oxygen redox. Jahn-Teller distortion of MnO<sub>6</sub> octahedra can be suppressed by modulating the local charge of Mn and Mn‒O distance through Mg/Ti dual doping. This leads to reduced Mn dissolution resulting in more reversible oxygen redox. Such stabilization significantly improves the electrochemical performance of Mg/Ti dual doped Na<sub>x</sub>Li<sub>y</sub>Mn<sub>1-y</sub>O<sub>2</sub>. Through this work, we show that promoting reversible oxygen redox can benefit from structural stabilization at local length scale, and that modifying the chemical environment through doping chemistry is an efficient strategy to promote local structural stability and thus, oxygen redox.</p>

scholarly journals Mitigation of Jahn–Teller distortion and Na+/vacancy ordering in a distorted manganese oxide cathode material by Li substitution

2021 ◽  
Author(s):  
Yanchen Liu ◽  
Chenchen Wang ◽  
Shuo Zhao ◽  
Lin Zhang ◽  
Kai Zhang ◽  
...  
Keyword(s):  
Cathode Material ◽  
Rate Capability ◽  
Sodium Ion ◽  
Sodium Ion Batteries ◽  
Teller Distortion ◽  
Oxide Cathode ◽  
Vacancy Ordering ◽  
Jahn Teller ◽  
Jahn Teller Distortion ◽  
Li Substitution

Li-Substitution in P′2-Na0.67MnO2 mitigates the anisotropic change of Mn–O bonds and Na/vacancy ordering, and hence significantly promotes its cycling stability and rate capability as a cathode material for sodium-ion batteries.

scholarly journals Electrochemical Modeling and Performance of a Lithium- and Manganese-Rich Layered Transition-Metal Oxide Positive Electrode

2015 ◽  
Vol 162 (4) ◽  
pp. A559-A572 ◽  
Author(s):  
Dennis W. Dees ◽  
Daniel P. Abraham ◽  
Wenquan Lu ◽  
Kevin G. Gallagher ◽  
Martin Bettge ◽  
...  
Keyword(s):  
Transition Metal ◽  
Metal Oxide ◽  
Transition Metal Oxide ◽  
Positive Electrode ◽  
Electrochemical Modeling ◽  
Layered Transition Metal ◽  
And Performance

Three-dimensional nitrogen-doped holey graphene and transition metal oxide composites for sodium-ion batteries

2019 ◽  
Vol 7 (1) ◽  
pp. 363-371 ◽  
Author(s):  
Dongfang Yang ◽  
Binghui Xu ◽  
Qinglan Zhao ◽  
X. S. Zhao
Keyword(s):  
Transition Metal ◽  
Metal Oxide ◽  
Ion Transport ◽  
Three Dimensional ◽  
Sodium Ion ◽  
Graphene Sheets ◽  
Sodium Ion Batteries ◽  
Nitrogen Doped ◽  
Oxide Composites ◽  
Charge Discharge

The unique macroporous architecture in combination with the presence of nanopores in graphene sheets facilitate ion transport during charge/discharge.

scholarly journals Nano-imaging of strain-tuned stripe textures in a Mott crystal

2021 ◽  
Vol 6 (1) ◽  
Author(s):  
A. S. McLeod ◽  
A. Wieteska ◽  
G. Chiriaco ◽  
B. Foutty ◽  
Y. Wang ◽  
...  
Keyword(s):  
Transition Metal ◽  
Transition Metal Oxides ◽  
Electrical Current ◽  
Teller Distortion ◽  
Self Organized ◽  
Imaging Results ◽  
Insulator Metal Transition ◽  
Jahn Teller ◽  
Nano Imaging ◽  
Jahn Teller Distortion

AbstractThe 4d transition metal perovskites Can+1RunO3n+1 have attracted interest for their strongly interacting electronic phases showing pronounced sensitivity to controllable stimuli like strain, temperature, and even electrical current. Through multi-messenger low-temperature nano-imaging, we reveal a spontaneous striped texture of coexisting insulating and metallic domains in single crystals of the bilayer ruthenate Ca3(TixRu1-x)2O7 across its first-order Mott transition at $$T \approx 95$$ T ≈ 95 K. We image on-demand anisotropic nucleation and growth of these domains under in situ applied uniaxial strain rationalized through control of a spontaneous Jahn-Teller distortion. Our scanning nano-susceptibility imaging resolves the detailed susceptibility of coexisting phases to strain and temperature at the transition threshold. Comparing these nano-imaging results to bulk-sensitive elastoresistance measurements, we uncover an emergent “domain susceptibility” sensitive to both the volumetric phase fractions and elasticity of the self-organized domain lattice. Our combined susceptibility probes afford nano-scale insights into strain-mediated control over the insulator-metal transition in 4d transition metal oxides.

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