Zn-Al₂O₃ Composites with High Aluminum Content and Nanostructured Al₂O₃/ZnO Prepared by Electrochemical Technique from Non-Suspended Solution

Abstract

Zn-Al 2 O 3 composites were electrodeposited from a non-suspended solution containing ZnSO 4 ·7H 2 O and Al 2 (SO 4 ) 3 ·14-18H 2 O using benzyldimethyltetradecylammonium chloride dehydrate (BDTAC) as the additive at an electrodeposition current of 50-500 A/m 2 with an air or a nitrogen bubbling. Initial layers with a thickness of approximately 1 µm were observed in the Zn-Al 2 O 3 composite on copper substrates. Furthermore, the Zn-Al 2 O 3 composite was composed of two different crystallographic areas, namely, nano-level size deposited grains with 20-60 nm in width and 100-200 nm in length, and closely packed fine particle deposits with a diameter of approximately 5 nm containing more than 26 atomic% aluminum. The nano-level size deposited grains and the closely packed fine particle deposits comprised nano-size ZnO and θ-Al 2 O 3 , respectively. The oxygen concentration in Zn-Al 2 O 3 composite by the air bubbling was higher than that in Zn-Al 2 O 3 composite by the nitrogen bubbling. In contrast, the zinc content ratio in Zn-Al 2 O 3 composite by the air bubbling was lower than that in Zn-Al 2 O 3 composite by the nitrogen bubbling. The aluminum concentration in closely packed fine particle deposits in Zn-Al 2 O 3 composite by the air bubbling was almost the same value as that in Zn-Al 2 O 3 composite by the nitrogen bubbling.

High-Performance InZn Alloy Anodes toward Practical Aqueous Zinc Batteries

“…The atomic percent of Al according to the EDX is less than 1 atom %. It is expected as the incorporation of Al into the Zn deposit is achieved through a precipitation mechanism similar to that presented in previous literature . In brief, as the local pH changes during the electrodeposition of Zn, Al 2 O 3 is formed that precipitates onto the growing film and then becomes trapped as new layers are formed .…”

“…The In and/or AlZn anodes in this work were prepared by electrodeposition (see the synthesis details in the Experimental Section), which is cost efficient compared to the high temperature alloy manufacturing and has a high yield, tunability, and scalability. ,,− On the basis of early reports of InZn and eutectic AlZn anodes coupled with our previous experience on electrodeposition Zn and CuZn, AlZn and InZn alloy anodes have been prepared via alloy/metal-matrix electrodeposition, which consists of electrodeposition in the presence of particles that are incorporated into the depositing film via convection. − Similar to the metal-matrix electrodeposition of metal and particles of metal oxides/carbides, the incorporation of Al 2 O 3 into Zn and InZn is achieved by precipitation due to the pH shift during electrodeposition …”

“…33−35 Similar to the metal-matrix electrodeposition of metal and particles of metal oxides/carbides, 36 the incorporation of Al 2 O 3 into Zn and InZn is achieved by precipitation due to the pH shift during electrodeposition. 36 Figures 2 and S1 show the XRD spectra of the electrodeposited AlZn, InZn, and commercial Zn foil. Side-by-side comparison shows that the commercial zinc foil (Figure S1) has a prominent (101) reflection peak at 43°2θ (JCPDF no.…”

“…It is expected as the incorporation of Al into the Zn deposit is achieved through a precipitation mechanism similar to that presented in previous literature. 36 In brief, as the local pH changes during the electrodeposition of Zn, Al 2 O 3 is formed that precipitates onto the growing film and then becomes trapped as new layers are formed. 36 The InZn surface (Figure 2e) shares some similarities with the AlZn in that the majority of the surface is composed of hexagonal platelets.…”

“…36 In brief, as the local pH changes during the electrodeposition of Zn, Al 2 O 3 is formed that precipitates onto the growing film and then becomes trapped as new layers are formed. 36 The InZn surface (Figure 2e) shares some similarities with the AlZn in that the majority of the surface is composed of hexagonal platelets. However, the stacking/overlap of these platelets is much more disorderly compared to the AlZn.…”