Engineering Polymer Glue towards 90% Zinc Utilization for 1000 Hours to Make High‐Performance Zn‐Ion Batteries

Abstract

Zinc (Zn) metal is considered the promising anode for "post-lithium" energy storage due to its high volumetric capacity, low redox potential, abundant reserve, and low cost. However, extravagant Zn is required in present Zn batteries, featuring low Zn utilization rate and devicescale energy/power densities far below theoretical values. The limited reversibility of Zn metal is attributed to the spontaneous parasitic reactions of Zn with aqueous electrolytes, that is, corrosion with water, passive by-product formation, and dendrite growth. Here, a new ionselective polymer glue coated on Zn anode is designed, isolating the Zn anode from the electrolyte by blocking water diffusion while allowing rapid Zn 2+ ion migration and facilitating uniform electrodeposition. Hence, a record-high Zn utilization of 90% is realized for 1000 h at high current densities, in sharp contrast to much poorer cyclability (usually < 200 h) at lower Zn utilization (50-85%) reported to date. When matched with the vanadium-based cathode, the resulting Zn-ion battery exhibited an ultrahigh device-scale energy density of 228 Wh kg −1 , comparable to commercial lithium-ion batteries.

Towards Understanding the Corrosion Behavior of Zinc‐Metal Anode in Aqueous Systems: From Fundamentals to Strategies

“…), [44,[121][122][123][124][125] and organic coatings are mainly some polymers (e. g., PVB, 502 glue, Gel-MA, etc.). [45,46,[126][127][128][129][130] The construction of an insulating nano protective layer on the surface of zinc foil by in situ or non-in situ methods is beneficial to mitigate zinc corrosion. For example, Zhao et al [125] deposited the TiO 2 layer on the zinc anode surface (Figure 16a).…”

“…The unique hydrophobic structure of IL skinny gel repels bulk water molecules from the coating, eliminating interfacial side reactions (Figure 17i). In particular, Jiao et al [129] designed a new ion-selective polymer gel (PG) capable of achieving an ultrahigh zinc utilization of 90 %, which can be attributed to the simultaneous inhibition of the spontaneous parasitic reaction of zinc with the aqueous electrolyte (Figure 17j). The above results indicate that the layer can effectively inhibit zinc corrosion and HER.…”

“…), [44,121–125] and organic coatings are mainly some polymers (e. g., PVB, 502 glue, Gel‐MA, etc.) [45,46,126–130] …”

Eliminating Stubborn Insulated Deposition by Coordination Effect to Boost Zn Electrode Reversibility in Aqueous Electrolyte

“…As shown in Figure 2A, after cycling in the control electrolyte, the surface of the zinc anode is covered by an insulating layer. The peak at about 9.8 o in the x-ray diffraction (XRD) (Figure 2B) spectrum confirms that the insulating layer is Zn 4 (OH) 6 SO 4 .5H 2 O (Jiao et al, 2021). This is due to the hydrogen evolution reaction of water in the aqueous electrolyte causing the partial formation of an alkaline environment in the electrolyte, which reacts with Zn 2+ to form an insoluble insulating solid precipitation and prevent the transfer of ions and electrons at the interface.…”

Strategies for Stabilization of Zn Anodes for Aqueous Zn-Based Batteries: A Mini Review

“…The Zn 2+ ·OSO 3 2− ion could constrain water molecules after a partial desolvation process and subsequently transferred to the Zn anode through MOF channels with proper configuration, resulting in high electrochemical stability. In addition, some organic coatings such as polyamide (PA) ( Zhao Z. et al, 2019 ), polymer glue ( Jiao et al, 2021 ), and Nafion film ( Cui et al, 2020 ), which normally show high adhesion to the substrate and low permeability of water molecules, can also serve as a HER barrier to protect the Zn anode from direct contact of water molecules, thus alleviating the undesirable gas evolution and Zn corrosion ( Figure 2E ).…”