TY - JOUR
T1 - Microstructural study on degradation mechanism of layered LiNi0.6Co0.2Mn0.2O2 cathode materials by analytical transmission electron microscopy
AU - Kim, Na Yeon
AU - Yim, Taeeun
AU - Song, Jun Ho
AU - Yu, Ji Sang
AU - Lee, Zonghoon
N1 - Publisher Copyright:
© 2016 Elsevier B.V. All rights reserved.
PY - 2016/3/1
Y1 - 2016/3/1
N2 - Electrochemical performance of lithium ion batteries is associated with structural and chemical stability of electrode materials. In the case of nickel-rich layered cathode materials LiNi0.6Co0.2Mn0.2O2, cation mixing, which results from the migration of transition metal ions into vacant lithium sites, is accelerated owing to similar ionic radii between nickel and lithium. However, the inevitable lattice distortions and chemical evolution have not been investigated intensely. In this paper, we report the structural evolution localized at surface regions through electron diffraction and high resolution imaging analyses with aberration-corrected transmission electron microscopy and scanning transmission electron microscopy. Repetition of volumetric change generates cracks and voids associated with deterioration of electrochemical performance. Structural change is related with (003) intensity in electron diffraction and it can be presented by dark field transmission electron microscopy imaging at a glance. Drastic structural degradation during early cycling shows relation with rapid capacity and voltage fade. Electron energy loss spectroscopy elucidates that the structural evolution caused by the migration of Ni ions accompanies chemical modification of Mn ions and creation of hole states at the O2p level. This study provides an insight into correlating structural and chemical evolution with degradation mechanism on battery performances of LiNi0.6Co0.2Mn0.2O2 cathode materials.
AB - Electrochemical performance of lithium ion batteries is associated with structural and chemical stability of electrode materials. In the case of nickel-rich layered cathode materials LiNi0.6Co0.2Mn0.2O2, cation mixing, which results from the migration of transition metal ions into vacant lithium sites, is accelerated owing to similar ionic radii between nickel and lithium. However, the inevitable lattice distortions and chemical evolution have not been investigated intensely. In this paper, we report the structural evolution localized at surface regions through electron diffraction and high resolution imaging analyses with aberration-corrected transmission electron microscopy and scanning transmission electron microscopy. Repetition of volumetric change generates cracks and voids associated with deterioration of electrochemical performance. Structural change is related with (003) intensity in electron diffraction and it can be presented by dark field transmission electron microscopy imaging at a glance. Drastic structural degradation during early cycling shows relation with rapid capacity and voltage fade. Electron energy loss spectroscopy elucidates that the structural evolution caused by the migration of Ni ions accompanies chemical modification of Mn ions and creation of hole states at the O2p level. This study provides an insight into correlating structural and chemical evolution with degradation mechanism on battery performances of LiNi0.6Co0.2Mn0.2O2 cathode materials.
KW - Collapse of layered structure
KW - Electron diffraction
KW - Electron energy loss spectroscopy
KW - High resolution (S)TEM
KW - Li-ion batteries
KW - LiNiCoMnO
UR - http://www.scopus.com/inward/record.url?scp=84954431291&partnerID=8YFLogxK
U2 - 10.1016/j.jpowsour.2016.01.023
DO - 10.1016/j.jpowsour.2016.01.023
M3 - Article
AN - SCOPUS:84954431291
SN - 0378-7753
VL - 307
SP - 641
EP - 648
JO - Journal of Power Sources
JF - Journal of Power Sources
ER -