Boosting activity of Ni(OH)2 toward alkaline energy storage by Co and Mn co-substitution.

Ni-based hydroxides nanomaterials are widely used in alkaline storage devices. Under the guidance of density functional theory calculations and experimental investigations, here, (Ni 0.8 Co 0.1 Mn 0.1)(OH) 2 is designed and prepared on CuO nanowire arrays, demonstrating Co and Mn co-substitution resulted in enhanced capacity and stability of Ni(OH) 2. The enhanced performance is mainly thanks to the low deprotonation energy and the facile electron transport, which results from the synergistic interactions among Ni, Co and Mn. Ni-Zn battery and alkaline hybrid supercapacitor with (Ni 0.8 Co 0.1 Mn 0.1)(OH) 2 (8.4 mg cm−2) as positive electrode can achieve infusive energy density of 605.2 and 270.1 Wh kg−1, respectively. The finding lay a foundation for further the design and fabrication of high-performance Ni-based nanomaterials for alkaline energy storage. By combining the experiment and density functional theory calculations, substituting part of Ni in Ni(OH) 2 with Co and Mn can improve its specific capacity and cycling stability, which are resulted from the low deprotonation energy and the facile electron transport. The (Ni 0.8 Co 0.1 Mn 0.1)(OH) 2 @CuO@CF composite electrode with a high mass loading of 8.4 mg cm−2 shows very high energy density in Ni-Zn battery (605.2 Wh kg−1) and alkaline hybrid supercapacitor (270.1 Wh kg−1). [Display omitted] • Co and Mn co-substituted Ni(OH)2 was grown on CuO nanowire arrays. • Substituting a part of Ni in Ni(OH)2 with Co and Mn can improve capacity. • The enhanced capacity was attributed mainly to the facile electron transport. • The core-shell heterostructures resulted in high energy density. [ABSTRACT FROM AUTHOR]