Synthesis, electrochemistry and First Principles Calculation studies of layered Li-Ni-Ti-O compounds
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AMMNS020.pdf
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Author(s)
Kang, Kisuk
Carlier, Dany
Reed, John
Arroyo, Elena M.
Meng, Shirley Y.
Ceder, Gerbrand
Date Issued
January 2004
Series/Report no.
Advanced Materials for Micro- and Nano-Systems (AMMNS);
Abstract
New layered cathode materials, Li₀.₉Ni₀.₄₅Ti₀.₅₅O₂, were synthesized by means of ion-exchange from Na₀.₉Ni₀.₄₅Ti₀.₅₅O₂. The degree of cation disordering in the material depends critically on the synthesis conditions. Longer times and higher temperatures in the ion-exchange process induced more cation disordering. However, the partially disordered phase showed better capacity retention than the least disordered phase. First principles calculations indicated this could be attributed to the migration of Ti⁺⁴ into the Li layer during the electrochemical testing, which seems to depend sensitively on the Ni⁺² -Ti⁺⁴ configuration in the transition metal layer. The poor conductivity of this material could also be the reason for its low specific capacity according to the Density of States (DOS) obtained from first principles calculations indicating that only Ni participates in the electronic conductivity.
Subjects
ion exchange
Li cathode
first principles calculation
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