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Phase transition kinetics of LiNi0.5Mn1.5O4 analyzed by temperature-controlled operando X-ray absorption spectroscopy
- Source :
- Physical Chemistry Chemical Physics. 18:1897
- Publication Year :
- 2015
-
Abstract
- LiNi0.5Mn1.5O4 (LNMO) is a promising positive electrode material for lithium ion batteries because it shows a high potential of 4.7 V vs. Li/Li(+). Its charge-discharge reaction includes two consecutive phase transitions between LiNi0.5Mn1.5O4 (Li1) ↔ Li0.5Ni0.5Mn1.5O4 (Li0.5) and Li0.5 ↔ Ni0.5Mn1.5O4 (Li0) and the complex transition kinetics that governs the rate capability of LNMO can hardly be analyzed by simple electrochemical techniques. Herein, we apply temperature-controlled operando X-ray absorption spectroscopy to directly capture the reacting phases from -20 °C to 40 °C under potential step (chronoamperometric) conditions and evaluate the phase transition kinetics using the apparent first-order rate constants at various temperatures. The constant for the Li1 ↔ Li0.5 transition (process 1) is larger than that for the Li0.5 ↔ Li0 transition (process 2) at all the measured temperatures, and the corresponding activation energies are 29 and 46 kJ mol(-1) for processes 1 and 2, respectively. The results obtained are discussed to elucidate the limiting factor in this system as well as in other electrode systems.
- Subjects :
- Phase transition
X-ray absorption spectroscopy
Absorption spectroscopy
Chemistry
020209 energy
Kinetics
Analytical chemistry
General Physics and Astronomy
chemistry.chemical_element
Nanotechnology
02 engineering and technology
021001 nanoscience & nanotechnology
Ion
Solution of Schrödinger equation for a step potential
Reaction rate constant
0202 electrical engineering, electronic engineering, information engineering
Lithium
Physical and Theoretical Chemistry
0210 nano-technology
Subjects
Details
- Language :
- English
- Volume :
- 18
- Database :
- OpenAIRE
- Journal :
- Physical Chemistry Chemical Physics
- Accession number :
- edsair.doi.dedup.....f0851320f02d2f795dbdbfa98d817079