TY - JOUR
T1 - Influences of Enhanced Entropy in Layered Rocksalt Oxide Cathodes for Lithium-Ion Batteries
AU - Kawaguchi, Tomoya
AU - Bian, Xiao
AU - Hatakeyama, Takuya
AU - Li, Hongyi
AU - Ichitsubo, Tetsu
N1 - Funding Information:
The authors thank Dr. Norihiko L. Okamoto, Dr. Hitoshi Tanimura, Dr. Kohei Shimokawa, and Masaya Yasuda for fruitful discussions and technical support. This research was supported by JSPS KAKENHI Grants 19K15307, 21H01646, and 18H05249. ICP analyses were supported by K. Nakayama and Y. Kabasawa at the Analytical Research Core for Advanced Materials, IMR, Tohoku University. EXAFS analyses were performed by using the IFEFFIT program code. Rietveld analyses were performed using Rietan-FP.
Publisher Copyright:
© 2022 American Chemical Society.
PY - 2022/4/25
Y1 - 2022/4/25
N2 - Utilizing high-entropy (HE) effects is a promising strategy to design cathode materials for rechargeable batteries. The fundamental understanding of the charge/discharge mechanism is, however, still nascent because of structural complexity and several redox elements in this class of materials. Therefore, the effects of the configurational entropy (Sconfig) on the electrode properties were studied in LiCr1/5Mn1/5Fe1/5Co1/5Ni1/5O2 (CMFCN) and LiCr1/4Mn1/4Co1/4Ni1/4O2 (CMCN), which are cathode materials for lithium-ion batteries (LIBs) prepared by adding Cr and Fe to the well-studied LiMn1/3Co1/3Ni1/3O2 (MCN) with a layered rocksalt structure to enhance the Sconfig. Single-phase materials were successfully synthesized by solution combustion synthesis (SCS). A reversible capacity of ∼150 mAh g-1 was observed in the first few cycles, deteriorating with increasing cycles in two degradation modes: rapid and slow degradation. Structural analyses revealed that the cation mixing of transition metals (TMs) such as Mn to Li sites and the migration of Cr and Fe to tetrahedral sites in the Li layer accounted for rapid and slow degradation, respectively. The present study demonstrated that this HE approach allows for utilization of elements that are not solely available for the layered rocksalt structure, whereas the characteristics of the constituent elements are inherited even in the entropy-enhanced environment of the oxides.
AB - Utilizing high-entropy (HE) effects is a promising strategy to design cathode materials for rechargeable batteries. The fundamental understanding of the charge/discharge mechanism is, however, still nascent because of structural complexity and several redox elements in this class of materials. Therefore, the effects of the configurational entropy (Sconfig) on the electrode properties were studied in LiCr1/5Mn1/5Fe1/5Co1/5Ni1/5O2 (CMFCN) and LiCr1/4Mn1/4Co1/4Ni1/4O2 (CMCN), which are cathode materials for lithium-ion batteries (LIBs) prepared by adding Cr and Fe to the well-studied LiMn1/3Co1/3Ni1/3O2 (MCN) with a layered rocksalt structure to enhance the Sconfig. Single-phase materials were successfully synthesized by solution combustion synthesis (SCS). A reversible capacity of ∼150 mAh g-1 was observed in the first few cycles, deteriorating with increasing cycles in two degradation modes: rapid and slow degradation. Structural analyses revealed that the cation mixing of transition metals (TMs) such as Mn to Li sites and the migration of Cr and Fe to tetrahedral sites in the Li layer accounted for rapid and slow degradation, respectively. The present study demonstrated that this HE approach allows for utilization of elements that are not solely available for the layered rocksalt structure, whereas the characteristics of the constituent elements are inherited even in the entropy-enhanced environment of the oxides.
KW - cation mixing
KW - charge compensation
KW - high-entropy oxides
KW - layered rocksalt structure
KW - lithium-ion batteries
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U2 - 10.1021/acsaem.1c03968
DO - 10.1021/acsaem.1c03968
M3 - Article
AN - SCOPUS:85129039517
SN - 2574-0962
VL - 5
SP - 4369
EP - 4381
JO - ACS Applied Energy Materials
JF - ACS Applied Energy Materials
IS - 4
ER -
