Al-doping induced superior lithium ion storage capability of LiNiO2 spheres

Single step synthesis of W-modified LiNiO2 using an ammonium tungstate flux

“…[51][52][53] Besides inuencing particle morphology, several studies have also shown that the incorporation of various dopant elements can also inuence the surface and/or structural stability of these materials. [54][55][56][57][58][59][60][61][62] As the tungstate ux has a low melting point (q m z 300 C), it is expected to melt during synthesis and distribute on the precursor material particles during the pre-annealing stage. At higher temperatures, the tungstate can react and introduce W into the LNO structure.…”

Mitigating the High-Charge Detrimental Phase Transformation in LiNiO2 Using Doping Engineering

“…The use of Al or Mg requires a higher doping concentration to effectively prevent the formation of the O1 phase, and Si is ineffective in stabilizing the O3 host structure, even with a higher doping concentration. The benefit of a higher doping concentration has also been experimentally confirmed in Al-doped LiNiO 2 , where a sufficient amount of Al doping (≥5%) is needed to reduce the detrimental effect of the O3-to-O1 phase transition …”

“…A range of dopants have been proposed to mitigate the O3-to-O1 phase transition and promote a more stable LiNiO 2 structure at high charge. Such dopants include W, Nb, Ti, Mn, Ga, Al, Cu, and Mg . In addition, some of these dopants have been proposed to exhibit a stabilizing effect on other high-energy-density layered cathodes.…”

“…For example, Guilmard et al reported that 10% Al doping in LiNi 1– y Al y O 2 is sufficient to suppress the phase transition and improve the cycling stability . Cao reported that 5% Al is the optimal doping concentration to achieve a uniform doping distribution and the best cycling performance compared to other Al doping concentrations and pristine LiNiO 2 , while Park et al reported that 1% Al doping does not lead to a noticeable cycling performance improvement in LiNi 0.9 Mn 0.1 O 2 . On the other hand, modeling is a powerful tool to help identify the intrinsic impact of composition and doping engineering on electrochemical performance, avoiding effects of synthesis and cell processing.…”

Demystifying the Lattice Oxygen Redox in Layered Oxide Cathode Materials of Lithium-Ion Batteries

“…LiNiO 2 (LNO) is presented as a typical layered phase with a cubic close-packed arrangement of O atoms. − It was reported by Dyer and co-workers in 1954. − The chemical formula of LNO could be presented by the general formula Li 1– z Ni 1+ z O 2 (0 ≤ z < 1). When the Li content ( z > 0.38) is low, the LNO presents a rock salt phase, where the Li and Ni completely occupy the 4a site, or alternatively, the Li 1– z Ni 1+ z O 2 presents a layer or spinel structure (Figure A). , …”