Improving thermal and electrochemical performances of LiCoO{sub 2} cathode at high cut-off charge potentials by MF{sub 3} (M=Ce, Al) coating

Journal Article · Fri Jan 15 04:00:00 EST 2016 · Materials Research Bulletin

DOI:https://doi.org/10.1016/J.MATERRESBULL.2015.09.020· OSTI ID:22584274

Aboulaich, Abdelmaula; Ouzaouit, Khalid; Faqir, Hakim; Kaddami, Abderrahman; Benzakour, Intissar; Akalay, Ismail

Highlights: • Fluoride metal is successfully coated on the surface of LiCoO{sub 2}. • Easy and scalable method is adopted for the synthesis of coated-LiCoO{sub 2}. • Appropriate amount of AlF{sub 3} or CeF{sub 3} is beneficial to reduce cation disorder. • The electrochemical performances of coated LiCoO{sub 2} is significantly enhanced at higher potential (cycling efficiency and reversible capacity). • The coated cathode exhibits excellent thermal stability highlighted by calorimetric technique. - Abstract: Surface coating of LiCoO{sub 2} remained one of the efficient methods to enhance its electrochemical and thermal performances, especially at high cut-off potential. In this work, MF{sub 3} (M = Ce, Al) coated LiCoO{sub 2} was synthesized via co-precipitation method followed by a solid state reaction at 400 °C. The morphology and structure of the modified cathode material were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD) and transmission electron microscopy (TEM). The results show that the fluoride compound MF{sub 3} is successfully coated on the surface of LiCoO{sub 2} cathode particles with an average layer thickness about 12 nm and 40 nm for AlF{sub 3} and CeF{sub 3}, respectively. The electrochemical tests show that the AlF{sub 3}-coating layer significantly enhances the cycling performance of LiCoO{sub 2} cathode material, even at high cut-off potential. While the bare LiCoO{sub 2} cathode displays fast fading at 4.6 V vs. Li{sup +}/Li cutoff potential, the surface-modified electrode exhibits the great capacity of 160 mAh g{sup −1} with excellent capacity retention on several cycles. We concluded that the electrochemical and the thermal enhancement at high potential are ascribed to the presence of MF{sub 3} coating layer which prevent the side reaction during the charge discharge process, alleviate the attack by the acidic electrolyte and reduce the damage of electrode structure.

• OSTI ID: 22584274
• Journal Information: Materials Research Bulletin, Journal Name: Materials Research Bulletin Vol. 73; ISSN MRBUAC; ISSN 0025-5408
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
ALUMINIUM FLUORIDES
CALORIMETRY
CATHODES
CERIUM FLUORIDES
COBALT OXIDES
COPRECIPITATION
ELECTROCHEMISTRY
INTERFACES
LAYERS
MICROSTRUCTURE
MORPHOLOGY
POTENTIALS
SCANNING ELECTRON MICROSCOPY
SURFACE COATING
SURFACES
TRANSMISSION ELECTRON MICROSCOPY
X-RAY DIFFRACTION