High-Capacity Nickel-Based Layered Oxides Containing Niobium Ions for Lithium-Ion Batteries

Abstract

Lithium-ion batteries have been widely used in recent years, from portable electronic devices to electric vehicles. Although LiNiO2, is expected to be ideal electrode materials for electric vehicle applications due to its high reversible capacity, Ni ions migrate from octahedral sites of transition metal layers to tetrahedral sites of adjacent Li layers during charging. This process is partly reversible process but Ni ions are left the tetrahedral sites of the Li layer after the continuous cycle test, which prevents the re-insertion of Li ions, resulting in capacity degradation. [1]To suppress the capacity degradation LiNiO2, the effect on the phase transition behavior by Nb substitution for Ni ions in LiNiO2 is examined.The samples with different Nb contents LixNi1–xNbxO2, are synthesized and tested as electrode materials. The Nb-substituted sample shows highly improved cycle characteristics compared with non-substituted LiNiO2. SEM observation of the samples reveals that the primary particles become smaller, suggesting that the Nb-substituted influences the crystallization process for LiNiO2. By comparing the results of electrochemical and structural characterizations for the samples with or without Nb substitution, the origin of the improvement of electrode reversibility is discussed in details.Reference [1] N. Ikeda et al., and N. Yabuuchi, Journal of Materials Chemistry A, 9, 15963 (2021).