Improved electrochemical reversibility of Li-Ni-Te-O cathode by local domain structure optimization
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Abstract
Novel layered oxide Li1+xNi3/4-5/4xTe1/4+1/4xO2 (x=0, 0.14, 0.33, 0.46, 0.50 and 0.60) cathodes were synthesized by a solid-state reaction method. A unique P1-like domain with a short-range order around Ni ions was found in the monoclinic C2/m crystal with x=0.33, which displays a loosely bonded local structure and increased Li+ mobility, enabling superior structural as well as electrochemical reversibility. The enhanced properties investigated by ex situ X-ray absorption spectroscopy (XAS), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and electrochemical characterization were corroborated to originate from the stable short- and long-range ordering structure along with the Ni electron redox. This study may open up new avenues for the development of Li-rich cathode materials with sufficiently good performance.
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