Nickel-cobalt hydroxide nanosheets: Synthesis, morphology and electrochemical properties

Barbora Schneiderová; Jan Demel; Alexander Zhigunov; Jan Bohuslav; Hana Tarábková; Pavel Janda; Kamil Lang

doi:10.1016/j.jcis.2017.03.096

Nickel-cobalt hydroxide nanosheets: Synthesis, morphology and electrochemical properties

J Colloid Interface Sci. 2017 Aug 1:499:138-144. doi: 10.1016/j.jcis.2017.03.096. Epub 2017 Mar 25.

Authors

Barbora Schneiderová¹, Jan Demel², Alexander Zhigunov³, Jan Bohuslav⁴, Hana Tarábková⁵, Pavel Janda⁵, Kamil Lang⁶

Affiliations

¹ Institute of Inorganic Chemistry of the Czech Academy of Sciences, v.v.i, Husinec-Řež 1001, 250 68 Řež, Czech Republic; Department of Inorganic Chemistry, Faculty of Science, Charles University, Hlavova 2030, 128 43 Praha 2, Czech Republic.
² Institute of Inorganic Chemistry of the Czech Academy of Sciences, v.v.i, Husinec-Řež 1001, 250 68 Řež, Czech Republic.
³ Institute of Macromolecular Chemistry of the Czech Academy of Sciences, v.v.i., Heyrovského nám. 2, 162 06 Praha 6, Czech Republic.
⁴ J. Heyrovský Institute of Physical Chemistry of the Czech Academy of Sciences, v.v.i., Dolejškova 3, 182 23 Praha 8, Czech Republic; University of Chemistry and Technology, Prague, Technická 5, 166 28 Praha 6, Czech Republic.
⁵ J. Heyrovský Institute of Physical Chemistry of the Czech Academy of Sciences, v.v.i., Dolejškova 3, 182 23 Praha 8, Czech Republic.
⁶ Institute of Inorganic Chemistry of the Czech Academy of Sciences, v.v.i, Husinec-Řež 1001, 250 68 Řež, Czech Republic. Electronic address: lang@iic.cas.cz.

PMID: 28365439
DOI: 10.1016/j.jcis.2017.03.096

Abstract

This paper reports the synthesis, characterization, and electrochemical performance of nickel-cobalt hydroxide nanosheets. The hydroxide nanosheets of approximately 0.7nm thickness were prepared by delamination of layered nickel-cobalt hydroxide lactate in water and formed transparent colloids that were stable for months. The nanosheets were deposited on highly oriented pyrolytic graphite by spin coating, and their electrochemical behavior was investigated by cyclic voltammetry in potassium hydroxide electrolyte. Our method of electrode preparation allows for studying the electrochemistry of nanosheets where the majority of the active centers can participate in the charge transfer reaction. The observed electrochemical response was ascribed to mutual compensation of the cobalt and nickel response via electron sharing between these metals in the hydroxide nanosheets, a process that differentiates the behavior of nickel-cobalt hydroxide nanosheets from single nickel hydroxide or cobalt hydroxide nanosheets or their physical mixture. The presence of cobalt in the nickel-cobalt hydroxide nanosheets apparently decreases the time of electrochemical activation of the nanosheet layer, which for the nickel hydroxide nanosheets alone requires more potential sweeps.

Keywords: Delamination; Electrode material; Exfoliation; Hydroxide nanosheets; Layered cobalt hydroxide; Layered nickel hydroxide.