Oxygen activity and peroxide formation as charge compensation mechanisms in Li2MnO3

2017 ◽  
Vol 5 (29) ◽  
pp. 15183-15190 ◽  
Author(s):  
Anika Marusczyk ◽  
Jan-Michael Albina ◽  
Thomas Hammerschmidt ◽  
Ralf Drautz ◽  
Thomas Eckl ◽  
...  
Keyword(s):  
Dft Calculations ◽  
Metal Oxides ◽  
Transition Metal Oxides ◽  
Cathode Materials ◽  
Driving Force ◽  
Charge Compensation ◽  
High Energy ◽  
Oxygen Release ◽  
Peroxide Formation ◽  
Compensation Mechanisms

Over-lithiated transition metal oxides are currently the most promising high energy cathode materials. DFT calculations show that Li2MnO3 becomes increasingly unstable upon delithiation and experiences a driving force for either oxygen release from the surface or peroxide formation in the bulk. Both mechanisms are shown to be detrimental for the electrochemistry.

scholarly journals Tuning local chemistry of P2 layered-oxide cathode for high energy and long cycles of sodium-ion battery

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Chenchen Wang ◽  
Luojia Liu ◽  
Shuo Zhao ◽  
Yanchen Liu ◽  
Yubo Yang ◽  
...  
Keyword(s):  
Phase Transition ◽  
Transition Metal ◽  
Metal Oxides ◽  
Transition Metal Oxides ◽  
Cathode Materials ◽  
Specific Capacity ◽  
High Energy ◽  
Sodium Ion ◽  
Sodium Ion Batteries ◽  
Two Phase

AbstractLayered transition-metal oxides have attracted intensive interest for cathode materials of sodium-ion batteries. However, they are hindered by the limited capacity and inferior phase transition due to the gliding of transition-metal layers upon Na+ extraction and insertion in the cathode materials. Here, we report that the large-sized K+ is riveted in the prismatic Na+ sites of P2-Na0.612K0.056MnO2 to enable more thermodynamically favorable Na+ vacancies. The Mn-O bonds are reinforced to reduce phase transition during charge and discharge. 0.901 Na+ per formula are reversibly extracted and inserted, in which only the two-phase transition of P2 ↔ P’2 occurs at low voltages. It exhibits the highest specific capacity of 240.5 mAh g−1 and energy density of 654 Wh kg−1 based on the redox of Mn3+/Mn4+, and a capacity retention of 98.2% after 100 cycles. This investigation will shed lights on the tuneable chemical environments of transition-metal oxides for advanced cathode materials and promote the development of sodium-ion batteries.

scholarly journals Cation-disordered rocksalt transition metal oxides and oxyfluorides for high energy lithium-ion cathodes

2020 ◽  
Vol 13 (2) ◽  
pp. 345-373 ◽  
Author(s):  
R. J. Clément ◽  
Z. Lun ◽  
G. Ceder
Keyword(s):  
Energy Density ◽  
Metal Oxides ◽  
Transition Metal Oxides ◽  
Short Range ◽  
Short Range Order ◽  
Lithium Ion ◽  
High Energy ◽  
High Energy Density ◽  
Detailed Understanding ◽  
The Impact

Cation-disordered rocksalt oxides and oxyfluorides are promising high energy density lithium-ion cathodes, yet require a detailed understanding of the impact of disorder and short-range order on the structural and electrochemical properties.

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