%0 Journal Article
%A Kim, Duho
%A Lim, Jin-Myoung
%A Park, Min-Sik
%A Cho, Kyeongjae
%A Cho, Maenghyo
%D 2016
%T Phase
Separation and d Electronic Orbitals on Cyclic Degradation in Li–Mn–O
Compounds: First-Principles Multiscale Modeling and Experimental Observations
%U https://acs.figshare.com/articles/journal_contribution/Phase_Separation_and_d_Electronic_Orbitals_on_Cyclic_Degradation_in_Li_Mn_O_Compounds_First-Principles_Multiscale_Modeling_and_Experimental_Observations/3457622
%R 10.1021/acsami.6b01595.s001
%2 https://acs.figshare.com/ndownloader/files/5431574
%K distortion
%K multiscale phase field model
%K cyclic degradation
%K Li 0 Mn 2 O 4
%K spinel
%K Jahn
%K show phase separation
%X A combined
study involving experiments and multiscale computational approaches
is conducted to propose a theoretical solution for the suppression
of the Jahn–Teller distortion which causes severe cyclic degradation.
As-synthesized pristine and Al-doped Mn spinel compounds are the focus
to understand the mechanism of the cyclic degradation in terms of
the Jahn–Teller distortion, and the electrochemical performance
of the Al-doped sample shows enhanced cyclic performance compared
with that of the pristine one. Considering the electronic structures
of the two systems using first-principles calculations, the pristine
spinel suffers entirely from the Jahn–Teller distortion by
Mn3+, indicating an anisotropic electronic structure, but
the Al-doped spinel exhibits an isotropic electronic structure, which
means the suppressed Jahn–Teller distortion. A multiscale phase
field model in nanodomain shows that the phase separation of the pristine
spinel occurs to inactive Li0Mn2O4 (i.e., fully delithiated) gradually during cycles. In contrast,
the Al-doped spinel does not show phase separation to an inactive
phase. This explains why the Al-doped spinel maintains the capacity of the
first charge during the subsequent cycles. On the basis of the mechanistic
understanding of the origins and mechanism of the suppression of the
Jahn–Teller distortion, fundamental insight for making tremendous
cuts in the cyclic degradation could be provided for the Li–Mn–O
compounds of Li-ion batteries.
%I ACS Publications