Prof. Daniela Kovacheva
Institute of General and Inorganic Chemistry, Bulgarian Academy of Sciences, Bd.11, Acad. Georgi Bontchev str., Sofia, 1113, Bulgaria.
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Academic Career Length
39Years (1988-Present)
(Calculated once Scilit publication data is synced: current year − year of first publication + 1)
Representative Publications
View All Publications1 March 2007 in Journal of Power Sources
Journal Article
DADoron Aurbach
Doron Aurbach
BMBoris Markovsky
Boris Markovsky
GSGregory Salitra
Gregory Salitra
EMElena Markevich
Elena Markevich
YTYossi Talyossef
Yossi Talyossef
Daniela Kovacheva +3
1 January 2010 in Journal of the Electrochemical Society
Journal Article
FAFrancis Amalraj
Francis Amalraj
Daniela KovachevaMTMichael Talianker
Michael Talianker
LZLeila Zeiri
Leila Zeiri
JGJudith Grinblat
Judith Grinblat
DADoron Aurbach
Doron Aurbach +3
We report herein on the synthesis of “layered-layered” integrated
<mml:math display="inline"><mml:mrow><mml:mi>x</mml:mi><mml:msub><mml:mrow><mml:mtext>Li</mml:mtext></mml:mrow><mml:mrow><mml:mn>2</mml:mn></mml:mrow></mml:msub><mml:msub><mml:mrow><mml:mtext>MnO</mml:mtext></mml:mrow><mml:mrow><mml:mn>3</mml:mn></mml:mrow></mml:msub><mml:mo>⋅</mml:mo><mml:mrow><mml:mo>(</mml:mo><mml:mrow><mml:mn>1</mml:mn><mml:mo>−</mml:mo><mml:mi>x</mml:mi></mml:mrow><mml:mo>)</mml:mo></mml:mrow><mml:msub><mml:mrow><mml:mtext>LiMn</mml:mtext></mml:mrow><mml:mrow><mml:mn>1</mml:mn><mml:mo>/</mml:mo><mml:mn>3</mml:mn></mml:mrow></mml:msub><mml:msub><mml:mrow><mml:mtext>Ni</mml:mtext></mml:mrow><mml:mrow><mml:mn>1</mml:mn><mml:mo>/</mml:mo><mml:mn>3</mml:mn></mml:mrow></mml:msub><mml:msub><mml:mrow><mml:mtext>Co</mml:mtext></mml:mrow><mml:mrow><mml:mn>1</mml:mn><mml:mo>/</mml:mo><mml:mn>3</mml:mn></mml:mrow></mml:msub><mml:msub><mml:mi mathvariant="normal">O</mml:mi><mml:mrow><mml:mn>2</mml:mn></mml:mrow></mml:msub></mml:mrow></mml:math>xLi2MnO3⋅(1−x)LiMn1/3Ni1/3Co1/3O2 materials ( <mml:math display="inline"><mml:mrow><mml:mi>x</mml:mi><mml:mo>=</mml:mo><mml:mn>0.3</mml:mn></mml:mrow></mml:math>x=0.3 , 0.5, and 0.7) using the self-combustion reaction in solutions containing metal nitrates and sucrose. The nanoparticles of these materials were obtained by further annealing of the as-prepared product in air at <mml:math display="inline"><mml:mrow><mml:mn>700</mml:mn><mml:mo>°</mml:mo><mml:mi mathvariant="normal">C</mml:mi></mml:mrow></mml:math>700°C for 1 h and submicrometric particles were obtained by further annealing at <mml:math display="inline"><mml:mrow><mml:mn>900</mml:mn><mml:mo>°</mml:mo><mml:mi mathvariant="normal">C</mml:mi></mml:mrow></mml:math>900°C for 22 h. The effect of composition on the electrochemical performance was explored in this work. By a rigorous study with high resolution transmission electron microscopy (HRTEM), it became clear that the syntheses with the above stoichiometries produce two-phase materials comprising nanodomains of both rhombohedral <mml:math display="inline"><mml:mrow><mml:msub><mml:mrow><mml:mtext>LiNiO</mml:mtext></mml:mrow><mml:mrow><mml:mn>2</mml:mn></mml:mrow></mml:msub></mml:mrow></mml:math>LiNiO2 -like and monoclinic <mml:math display="inline"><mml:mrow><mml:msub><mml:mrow><mml:mtext>Li</mml:mtext></mml:mrow><mml:mrow><mml:mn>2</mml:mn></mml:mrow></mml:msub><mml:msub><mml:mrow><mml:mtext>MnO</mml:mtext></mml:mrow><mml:mrow><mml:mn>3</mml:mn></mml:mrow></mml:msub></mml:mrow></mml:math>Li2MnO3 structures, which are closely integrated and interconnected with one another at the atomic level. Stable reversible capacities <mml:math display="inline"><mml:mrow><mml:mo>∼</mml:mo><mml:mn>220</mml:mn><mml:mspace width="0.5em"></mml:mspace><mml:mtext>mAh</mml:mtext><mml:mo>/</mml:mo><mml:mi mathvariant="normal">g</mml:mi></mml:mrow></mml:math>∼220mAh/g were obtained with composite electrodes containing submicrometer particles of <mml:math display="inline"><mml:mrow><mml:mn>0.5</mml:mn><mml:msub><mml:mrow><mml:mtext>Li</mml:mtext></mml:mrow><mml:mrow><mml:mn>2</mml:mn></mml:mrow></mml:msub><mml:msub><mml:mrow><mml:mtext>MnO</mml:mtext></mml:mrow><mml:mrow><mml:mn>3</mml:mn></mml:mrow></mml:msub><mml:mo>⋅</mml:mo><mml:mn>0.5</mml:mn><mml:msub><mml:mrow><mml:mtext>LiMn</mml:mtext></mml:mrow><mml:mrow><mml:mn>1</mml:mn><mml:mo>/</mml:mo><mml:mn>3</mml:mn></mml:mrow></mml:msub><mml:msub><mml:mrow><mml:mtext>Ni</mml:mtext></mml:mrow><mml:mrow><mml:mn>1</mml:mn><mml:mo>/</mml:mo><mml:mn>3</mml:mn></mml:mrow></mml:msub><mml:msub><mml:mrow><mml:mtext>Co</mml:mtext></mml:mrow><mml:mrow><mml:mn>1</mml:mn><mml:mo>/</mml:mo><mml:mn>3</mml:mn></mml:mrow></mml:msub><mml:msub><mml:mi mathvariant="normal">O</mml:mi><mml:mrow><mml:mn>2</mml:mn></mml:mrow></mml:msub></mml:mrow></mml:math>0.5Li2MnO3⋅0.5LiMn1/3Ni1/3Co1/3O2 . Structural aspects, activation of the monoclinic component, and stabilization mechanisms are thoroughly discussed using Raman spectroscopy, solid-state NMR, HRTEM, and X-ray diffraction (including Rietveld analysis) in conjunction with electrochemical measurements. This work provides a further indication that this family of integrated compounds contains the most promising cathode materials for high energy density Li-ion batteries.1 April 2009 in Journal of Power Sources
Journal Article
SMSurendra K. Martha
Surendra K. MarthaHSHadar Sclar
Hadar Sclar
ZFZvi Szmuk Framowitz
Zvi Szmuk Framowitz
Daniela KovachevaNSNikolay Saliyski
Nikolay Saliyski
DADoron Aurbach
Doron Aurbach
+4
1 April 2009 in Journal of Power Sources
Journal Article
SMS.K. Martha
S.K. MarthaEME. Markevich
E. Markevich
VBV. Burgel
V. Burgel
GSG. Salitra
G. Salitra
EZE. Zinigrad
E. Zinigrad
NSN. Saliyski
N. Saliyski
+11
1 June 1998 in Solid State Ionics
Journal Article
Daniela KovachevaKPK. Petrov
K. Petrov
1 January 2007 in Journal of the Electrochemical Society
Journal Article
YTYosef Talyosef
Yosef Talyosef
BMBoris Markovsky
Boris Markovsky
RLRonit Lavi
Ronit Lavi
GSGregory Salitra
Gregory Salitra
DADoron Aurbach
Doron Aurbach
Radostina Stoyanova +3
We report on a rigorous comparative study of nano- and microparticles of
<mml:math display="inline"><mml:mrow><mml:mi mathvariant="normal">Li</mml:mi><mml:msub><mml:mi mathvariant="normal">Mn</mml:mi><mml:mrow><mml:mn>1.5</mml:mn></mml:mrow></mml:msub><mml:msub><mml:mi mathvariant="normal">Ni</mml:mi><mml:mrow><mml:mn>0.5</mml:mn></mml:mrow></mml:msub><mml:msub><mml:mi mathvariant="normal">O</mml:mi><mml:mrow><mml:mn>4</mml:mn></mml:mrow></mml:msub></mml:mrow></mml:math>LiMn1.5Ni0.5O4 spinel as cathode materials for Li-ion batteries. The stability of these materials in <mml:math display="inline"><mml:mrow><mml:mi mathvariant="normal">Li</mml:mi><mml:mi mathvariant="normal">P</mml:mi><mml:msub><mml:mi mathvariant="normal">F</mml:mi><mml:mrow><mml:mn>6</mml:mn></mml:mrow></mml:msub></mml:mrow></mml:math>LiPF6 /alkyl carbonate solutions in temperatures up to <mml:math display="inline"><mml:mrow><mml:mn>70</mml:mn><mml:mo>°</mml:mo><mml:mi mathvariant="normal">C</mml:mi></mml:mrow></mml:math>70°C was explored. Capacity, cycling, rate capabilities, and impedance behavior were also studied. The methods included X-ray diffraction, Raman, X-ray photelectron, Fourier transform infrared, and electron paramagnetic resonance spectroscopies, and electron microscopy, in conjunction with standard electrochemical techniques: voltammetry, chronopotentiometry, and impedance spectroscopy. These materials show an impressive stability in solutions at elevated temperature. The use of nanomaterials was advantageous for obtaining a better rate capability of <mml:math display="inline"><mml:mrow><mml:mi mathvariant="normal">Li</mml:mi><mml:msub><mml:mi mathvariant="normal">Mn</mml:mi><mml:mrow><mml:mn>1.5</mml:mn></mml:mrow></mml:msub><mml:msub><mml:mi mathvariant="normal">Ni</mml:mi><mml:mrow><mml:mn>0.5</mml:mn></mml:mrow></mml:msub><mml:msub><mml:mi mathvariant="normal">O</mml:mi><mml:mrow><mml:mn>4</mml:mn></mml:mrow></mml:msub></mml:mrow></mml:math>LiMn1.5Ni0.5O4 electrodes. <mml:math display="inline"><mml:mrow><mml:mi mathvariant="normal">Li</mml:mi><mml:msub><mml:mi mathvariant="normal">Mn</mml:mi><mml:mrow><mml:mn>1.5</mml:mn></mml:mrow></mml:msub><mml:msub><mml:mi mathvariant="normal">Ni</mml:mi><mml:mrow><mml:mn>0.5</mml:mn></mml:mrow></mml:msub><mml:msub><mml:mi mathvariant="normal">O</mml:mi><mml:mrow><mml:mn>4</mml:mn></mml:mrow></mml:msub></mml:mrow></mml:math>LiMn1.5Ni0.5O4 particles develop a unique surface chemistry in solutions that passivates and protects them from detrimental interactions with solution species at elevated temperatures.About Me
Daniela Kovacheva graduated in Physics in 1983 from Sofia
University. In 1992, she obtained a PhD degree in Solid State Chemistry. Since
2012, she has been working as a Professor and Head of the Laboratory of Crystal
Chemistry of Composite Materials at the Institute of General and Inorganic
Chemistry, Bulgarian Academy of Sciences. Her research covers the synthesis and
structure of inorganic materials and composites with interesting optical,
mechanical, electrical, magnetic, sensitizing, and catalytic properties, namely
the development of non-classical routes for material preparation, including
methods of soft chemistry, solution combustion synthesis, and sonochemical
synthesis. Other activities are focused on X-ray diffraction methods, including
qualitative and quantitative phase analysis, diffraction line broadening
analysis (crystallite size and microstrain distribution), and Rietveld
structure refinement. She has completed a long-term specialization in neutron
diffraction (1990) at the Max von Laue-Paul Langevin Institute, Grenoble
(France). She is a member of the Commission of Powder Diffraction at the
International Union of Crystallography.