Nanocomposites and Nanomaterials

Electrochemical hydrogenation of Ni nanopowders
Zavaliy I.Yu.1, Kytsya A.R.1,2, Verbovytskyy Yu.V.1, Lyutyy P.Ya.1
1 Physico-Mechanical Institute of the NAS of Ukraine. 5, Naukova str., 79060, Lviv, Ukraine. E-mail: zavaliy@ipm.lviv.ua
2 Department of Physical Chemistry of Fossil Fuels InPOCCC NAS of Ukraine. Naukova Str., 3a, Lviv, Ukraine.

In last decades an influence of different additives (including nanoadditives) on the corrosion stability and hydrogenation performance of the Mg-based electrodes is studied. For example, it was reported that nano Ag-graphene addition to the Mg-Ni-La alloy [1] as well as Ni nanopowder to the LaMg3 alloy improved charge- discharge parameters of the electrodes [2]. But despite the numerous papers devoted to this problem the mechanism of influence of nanoadditives is not clear. That is why herein we report the results of electrochemical investigations of hydro- genation of crystalline and amorphous Ni nanopowders, which have been synthe- sized by reduction of Ni2+/Ni(OH)2 by hydrazine or NaBH4 in polyol/water solutions.

XRD patterns of crystalline and amorphous Ni nanopowders	The obtained Ni powders have been investigated by using SEM, TEM, EDX and XRD. It was established that nickel in amorphous state can be obtained using NaBH4 as a reducing agent. On the contrary, using of N2H4 as a reductant leads to the formation of Ni nanopowders with a crystalline structure (see Figure). It was found that Ni electrodes possess own discharge capacity. The use of the amorphous and crystalline Ni powders as additive to Mg-based electrodes demonstrated the substantial influence on their discharge capacity. 	

1.	Huang L., et al. Graphene/silver nanocomposites stabilize Mg-Ni-La electrode alloys and enhance electrochemical performance // J. Alloy Compd.- 2017.-694.-P. 1140-1148.
2.	Zhang H., et al. Nano-Ni induced surface modification relevant to the hydrogenation performances in La-Mg based alloys // Appl. Surf. Sci.-2018.- 439.-P. 18-23.