Insight into an electrodeposition process of bimetal co-substituted α-Ni(OH) ₂ preparation

The energy crisis and environmental challenges have accelerated the development of new energy sources and energy storage devices, highlighting the importance of research on Ni(OH) 2 , a widely used active material in energy storage systems. At present, research on Ni(OH) 2 mainly focuses on the preparation of α-Ni(OH) 2 and improvements in its structural stability. To obtain α-Ni(OH) 2 with enhanced durability, this work attempts to directly prepare Al–Mn co-substituted α-Ni(OH) 2 through an one-step electrodeposition method. The results indicate that Mn 2+ may influence the local pH at the cathode−catholyte interface via the formation of coordination complexes with OH – , thereby affecting the co-deposition of Al 3+ . Samples exhibiting a Mn fraction similar to the initial electrolyte and an Al fraction about 2.5−time as that in the initial electrolyte ratio can be produced using MnCl 2 –AlCl 3 –NiCl 2 solutions as both anolyte and catholyte. Additionally, samples with a Mn ratio of about one-tenth of the original electrolyte and an Al ratio comparable to the initial value can be achieved by alternately using MnCl 2 –AlCl 3 –NiCl 2 and AlCl 3 –NiCl 2 solutions as the anolyte and catholyte. The phase characteristics of the electrodeposited Al−Mn co-substituted α-Ni(OH) 2 remained after 30 days of immersion in 6 M KOH, and their alkaline stability surpassed that of samples prepared by chemical precipitation.