Rheological Phase Synthesis and Electrochemical Properties of Mg-Doped LiNi[sub 0.8]Co[sub 0.2]O[sub 2] Cathode Materials for Lithium-Ion Battery

Abstract

LiNi 0.8 Co 0.2 O 2 and Mg-doped LiNi 0.8 Co 0.2 O 2 have been synthesized via the rheological phase reaction route. The particle size distribution is obtained using laser scattering measurements. The morphological features are observed by a scanning electron microscope. Electrochemical tests show that the Mg-doped LiNi 0.8 Co 0.2 O 2 exhibits an improved capacity, cycling stability, and rate performances compared to undoped samples. The samples are also characterized by cyclic voltammetry and electrochemical impedance spectroscopy. Furthermore, possible mechanisms of Mg-doping are discussed based on the defect reaction.

Successes and failures of Hubbard-corrected density functional theory: The case of Mg doped LiCoO2

“…Other mechanisms for charge compensation can involve the formation of vacancy, interstitial and anti-site defects, and defect complexes. 44 51,55 have shown that, of these ionic defects, the dominant one under typical synthesis conditions is the anti-site Co + Li defect. The other intrinsic defects have high formation en-ergies and are expected to have a low concentration.…”

“…It has been proposed that Mg is initially on the transition metal sites, but it migrates to the inter-layer spaces after initial cycling. 22,[41][42][43] Xiang et al 44 37 found that Mg cations are mainly on Ni sites. They argued that Mg stabilizes the NiO 2 slab, preventing thermal and cycling decomposition.…”

Synthesis, structural and electrochemical properties of LiNi0.79Co0.1Mn0.1Cr0.01O2 via fast co-precipitation

“…Nevertheless, there still remain many problems, such as low initial coulombic efficiency, poor rate capacity and poor cyclability due to cation mixing (some Ni 2+ ions of Ni layer move to Li layer) and instable structure [7,8]. Many authors reported that partial transition metal substitution for Ni in Li(Ni 1−x M x )O 2 (M = metal) can modify the structure and improve electrochemical properties [9][10][11][12][13][14][15]. Ohzuku et al found that partial Al substitution for Ni effectively stabilizes the structure of LiNiO 2 system [9].…”

Understanding the role of Zr4+ cation in improving the cycleability of LiNi0.8Co0.15Zr0.05O2 cathodes for Li ion rechargeable batteries

“…Several dopant cations such as Ca 2+ , Sr 2+ , Mg 2+ , Ga 3+ , Rh 3+ , Ti 4+ , Zr 4+ has been introduced to improve the electrochemical characteristics of LNCO cathodes [2][3][4][5][6][7][8][9][10]. These dopant cations are termed inert as their valence state does not get changed during charge-discharge cycling.…”