Polyethylene glycol coating on zinc powder surface: Applications in dendrite-free zinc anodes with enhanced utilization rate

Abstract

Zinc powder (Zn-P) anode is a more practical choice in industrial production compared with zinc foil, benefiting from its high exposed surface area and potential utilization rate for achieving high energy density. However, Zn-P-based anode still suffers from huge side-reaction (e.g., hydrogen evolution) and uncontrolled dendrite growth, which limit its further application. Herein, a polyethylene glycol (PEG) coating was introduced onto the surface of zinc powder to achieve corrosion-resistant, dendrite-free and high utilized zinc anodes. The PEG coating not only effectively suppressed the hydrogen evolution reaction, but also induced the ordered plating/stripping of Zn2+ via the oriented and preferred Zn (002) planes. Thus, the assembled Zn-P/PEG anode symmetric battery achieved a long cycle life of 1000 h at current densities of 5 mA cm−2. Furthermore, the energy density of Zn-P/PEG based full cell is nearly 1.7 times of that assembled by Zn foil anode. This work is the first to achieve the inhibition of hydrogen evolution on the surface of zinc powder while inducing the ordered deposition of zinc ions, achieving the effect of killing two birds with one stone. The proposed strategy of coating zinc powder with polymer provides new prospects for the modification of zinc powder anodes.