Nanosized Effect on Electronic/Local Structures and Specific Lithium-Ion Insertion Property in TiO2–B Nanowires Analyzed by X-ray Absorption Spectroscopy
Effects of lattice defects on cathode properties of LiMn2O4 synthesized at low temperatures were
investigated. LiMn2O4 powders were synthesized by a sol-gel method. The specific capacities of
LiMn2O4 decreased from 134 to 81 mAh g-1 with decreasing heating temperature from 750 to 200°C.
X-ray absorption spectroscopy showed that a large amount of lattice defects such as cation
vacancies existed and cation mixing occurred in LiMn2O4 calcined at low temperatures. It was
found that the low specific capacities of LiMn2O4 calcined at low temperatures were attributed to
these lattice defects.
AbstractLiCoO2 and LiNiO2, two important cathode materials for Li-ion batteries, were studied in their respective bulk and thin-film form. X-ray absorption spectroscopy (XAS) has been used to probe the local atomic structure and structural defects in the thin-film and bulk cathodes. Results comparing Li(Co,Ni)O2 in the bulk and thin-film forms suggests a correlation between intrinsic stress and local strain in the thin-film. This local strain is manifested by a collapse of the six-fold rotational symmetry within the metal-metal layer of the Li(Co,Ni)O2 system into a two fold one. The relationship between annealing conditions and the resulting local strain in these films is examined.
Improvement of Ultra Soft X-ray Absorption Spectroscopy and Photoelectron Spectroscopy Beamline for Studies on Related Materials and Cathodes of Lithium Ion Batteries