Regulating Interfacial Desolvation and Deposition Kinetics Enables Durable Zn Anodes with Ultrahigh Utilization of 80%

Abstract

Rechargeable aqueous zinc ion batteries (ZIBs) represent a promising technology for large‐scale energy storage due to their high capacity, intrinsic safety and low cost. However, Zn anodes suffer from poor reversibility and cycling stability caused by the side‐reactions and dendrite issues, which limit the Zn utilization in the ZIBs. Herein, to improve the durability of Zn under high utilization, an aluminum‐doped zinc oxide (AZO) interphase is presented. The AZO interphase inhibits side reactions by isolating active Zn from the bulk electrolyte, and enables facile and uniform Zn deposition kinetics by accelerating the desolvation of hydrated Zn2+ and homogenizing the electric field distribution. Accordingly, the AZO‐coated Zn (AZO@Zn) anode exhibits a long lifespan of 600 h with Zn utilization of 34.1% at the current density of 10 mA cm−2. Notably, even under ultrahigh Zn utilization of 80%, the AZO@Zn remains stable cycling over 200 h. Meanwhile, the V2O5/AZO@Zn full cell with limited Zn excess displays high capacity retention of 86.8% over 500 cycles at 2 A g−1. This work provides a simple and efficient strategy to ensure the reversibility and durability of Zn anodes under high utilization conditions, holding a great promise for commercially available ZIBs with competitive energy density.

Kinetics‐Boosted Effect Enabled by Zwitterionic Hydrogel Electrolyte for Highly Reversible Zinc Anode in Zinc‐Ion Hybrid Micro‐Supercapacitors

“…[64] Wherein, desolvation of hydrated Zn 2+ is the rate-limiting procedure of Zn deposition on account of the large desolvation penalty caused by the strong coulombic interactions between Zn 2+ and its surrounding solvent H 2 O. [22,65] Density functional theory calculations were carried out to gain insight into the desolvation of hydrated Zn 2+ in PASHE. As seen in Figure 5a, the strongly polar sulfobetaine sulfonate anion of the polymeric matrix in PASHE owns stronger adsorption of Zn 2+ with a binding energy of −11.69 eV, which is much more negative than that of Zn 2+ -H 2 O (−4.52 V), shedding light on the preferential combination of Zn 2+ and sulfobetaine sulfonate anions.…”

“…[ 68 ] Due to the superior desolvation effect of PASHE, the Zn|PASHE|Zn cell displays a lower nucleation overpotential (239 mV) than the Zn|LE|Zn cell (295 mV) at 5 mA cm −2 and 5 mAh cm −2 , manifesting a dramatically lowered Zn deposition barrier at the Zn–PASHE interface (Figure S13, Supporting Information). [ 22 ] The low nucleation resistance induced by PASHE increases Zn nucleation sites, which favors the uniform and fine‐grained Zn deposit with finer nucleus. [ 69 ] Furthermore, chronoamperometry is carried out to characterize the Zn deposition behavior because the variation in the current–time profile can sensitively reflect the nucleation process and surface change.…”

“…The large desolvation penalty slows deposition kinetics and accelerates hydrogen evolution reaction. [22,23] This penalty can be reduced by changing the solvation structure of the hydrated Zn 2+ through zwitterionic Zn-oriented groups. [20] Thus, developing polyzwitterions-based hydrogel electrolytes is an effective strategy to fulfill rapid transport and desolvation kinetics.…”

Construction of Bio‐inspired Film with Engineered Hydrophobicity to Boost Interfacial Reaction Kinetics of Aqueous Zinc–Ion Batteries

“…[ 17,18 ] During the continuous Zn 2+ insertion process, hydrated Zn 2+ species will be transferred to the cathode–electrolyte interface and subsequently desolvated before insertion into the cathode host ([Zn(H 2 O) 6 ] 2+ →Zn 2+ +6H 2 O). [ 17,19–21 ] Thus, the battery system consumes extra energy to expel the Zn 2+ from their surrounding solvation shells, yielding energy losses due to undesirable desolvation process. This also diminishes the Zn 2+ ion migration rate, interfacial charge transfer rate, and modifies the mass transfer behavior of electrolyte solute.…”

“…host ([Zn(H 2 O) 6 ] 2+ →Zn 2+ +6H 2 O). [17,[19][20][21] Thus, the battery system consumes extra energy to expel the Zn 2+ from their surrounding solvation shells, yielding energy losses due to undesirable desolvation process. This also diminishes the Zn 2+ ion migration rate, interfacial charge transfer rate, and modifies the mass transfer behavior of electrolyte solute.…”