Fabrication of layered double hydroxide by the liquid phase deposition

The optimum coordination structure of nickel-fluoro complexes for the preparation of Ni-Al layered double hydroxide(LDH)by liquid phase deposition(LPD)process and the diverse anion exchange properties of as-deposited Ni-Al on·-alumina powder were quantitatively evaluated for the industrial application of new positive material for alkali secondary batteries.The[NiF6-x-y(NH3)x(OH-)y]n was more suitable than[NiF6]4-as the precursor of the deposition of Ni-Al LDH in the LPD reaction，and the improved LPD reaction achieved the synthesis of high purity and high crystallinity Ni-Al LDH.All anion-exchanged Ni-Al LDHs for OH-，Cl--，SO42--，and CH3COO--forms kept the high crystallinity and showed the enlargement of interlayer distances.The tilting angle of the intercalated CH3COO-anions was about15°.Anion-exchange capacity remained constant at a minimum of 0.8meq g-1in pH&gt；10，increased as pH decreased，and reached a maximum of 8meq g-1at pH2.Anion-exchange of OH-form of Ni-Al LDH was accelerated by the neutralization of hydroxide ions in interlayers，in addition，the anion-exchange capacity and the crystallinity of Ni-Al LDH could be controlled by the amount of doped aluminum.

The optimum coordination structure of nickel-fluoro complexes for the preparation of Ni-Al layered double hydroxide(LDH) by liquid phase deposition(LPD) process and the diverse anion exchange properties of as-deposited Ni-Al on ・-alumina powder were quantitatively evaluated for the industrial application of new positive material for alkali secondary batteries. The [NiF6-x-y(NH3)x(OH-)y]n+ was more suitable than [NiF6]4- as the precursor of the deposition of Ni-Al LDH in the LPD reaction, and the improved LPD reaction achieved the synthesis of high purity and high crystallinity Ni-Al LDH. All anion-exchanged Ni-Al LDHs for OH--, Cl--, SO42--, and CH3COO--forms kept the high crystallinity and showed the enlargement of interlayer distances. The tilting angle of the intercalated CH3COO- anions was about 15°. Anion-exchange capacity remained constant at a minimum of 0.8meq g-1in pH >10, increased as pH decreased, and reached a maximum of8 meq g-1at pH 2. Anion-exchange of OH--form of Ni-Al LDH was accelerated by the neutralization of hydroxide ions in interlayers, in addition, the anion-exchange capacity and the crystallinity of Ni-Al LDH could be controlled by the amount of doped aluminum ions.