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Electrochemical Properties and Crystal Structure of Li+/H+ Cation-Exchanged LiNiO2

preprint
submitted on 05.01.2020, 08:10 and posted on 08.01.2020, 20:23 by Takahiro Toma, Ryo Maezono, Kenta Hongo
LiNiO2 has high energy density but easily reacts with moisture in the atmosphere and deteriorates. We performed qualitative and quantitative evaluations of the degraded phase of LiNiO2 and the influence of the structural change on the electrochemical properties of the phase. Li1-xHxNiO2 phase with cation exchange between Li+ and H+ was confirmed by thermogravimetric analysis and Karl Fischer titration measurement. As the H concentration in LiNiO2 increased, the rate capability deteriorated, especially in the low-temperature range and under low state of charge. Experimental and density functional theory (DFT) calculation results suggested that this outcome was due to increased activation energy of Li+ diffusion owing to cation exchange. Rietveld analysis of X-ray diffraction and DFT calculation confirmed that the c lattice parameter and Li-O layer reduced because of the Li+/H+ cation exchange. These results indicate that LiNiO2 modified in the atmosphere has a narrowed Li-O layer, which is the Li diffusion path, and the rate characteristics are degraded.

History

Email Address of Submitting Author

takahiro.toma.r3@smm-g.com

Institution

Japan Advanced Institute of Science and Technology (JAIST)

Country

Japan

ORCID For Submitting Author

0000-0001-8698-9742

Declaration of Conflict of Interest

The authors declare no conflict of interest

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in ACS Applied Energy Materials

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