Achieving Highly Reversible Zn Anodes by Inhibiting the Activity of Free Water Molecules and Manipulating Zn Deposition in a Hydrogel Electrolyte

Zinc metal anodes have been widely used in aqueous Zn-ionbatteries.However, side reactions and zinc dendrites were generated on the Znanode during cycling. These problems lead to short circuits and poorlong-cycle stability of the battery. This paper reports a multiplecross-linked PAM-CMC-GG (PCG) gel electrolyte. Zinc uniformly depositedon (002) crystal surfaces under the combined effect of carboxylicacid and amide groups in PCG gel electrolyte. The behavior effectivelyreduces the generation of zinc dendrites. In addition, the abundanthydroxyl groups in PCG can inhibit the activity of free water andreduce the generation of solvent structures, thus suppressing theformation of byproducts. As a result, the symmetric cells assembledwith PCG gel electrolyte operated stably for over 450 h at a currentdensity of 5 mA cm(-2), and Zn/Cu asymmetric cellsmaintained a coulomb efficiency (CE) of 99.2% for more than 500 cycles.It is expected that PCG gel electrolyte provides promising prospectsfor the practical application of gel electrolytes in energy storagedevices.