Bifunctional Hydrated Gel Electrolyte for Long‐Cycling Zn‐Ion Battery with NASICON‐Type Cathode

Abstract

Aqueous Zn-ion batteries are promising and safe energy storage technologies. However, current aqueous electrolyte Zn-ion battery technology is hindered by undesirable reactions between the electrolyte and electrodes, which can lead to Zn dendrite growth, gas evolution, and cathode degradation. In this study, a hydrated gel electrolyte (HGE) that combines adiponitrile (ADN) and Zn(ClO 4 ) 2 •6H 2 O in a polymeric framework is created. ADN is found to stabilize the interface between the electrolyte and anode/cathode, enabling smooth Zn stripping/plating and reducing parasitic reactions. The HGE is simple to fabricate, inexpensive, safe, and flexible. Zn/HGE/Zn symmetrical cells can cycle more than 1000 h at 0.5 mA cm −2 and 2000 h at 0.2 mA cm −2 without short-circuiting, indicating effective suppression of Zn dendrites. Moreover, with a NASICON-type Sr-doped Na 3 V 2 (PO 4 ) 3 (SNVP) cathode, a Zn/HGE/SNVP full cell can be cycled over 8000 times at 10 C while retaining a high capacity of 90 mAh g −1 .

Hydrated Deep Eutectic Electrolytes for High‐Performance Zn‐Ion Batteries Capable of Low‐Temperature Operation

“…[ 7 ] However, parasitic reactions at the interface between Zn metal anodes (ZMAs) and AEs, such as the uncontrolled growth of dendrites, H 2 evolution, corrosion, and passivation, cause ZMAs to degrade, limiting the commercializability of ZIBs. [ 8–10 ]…”

Eutectic Electrolytes Chemistry for Rechargeable Zn Batteries

“…This is thanks to the strong H‐bond interactions among eutectic composition and gel/polymer network, further suppressing water reactivity and reinforcing the stability of SSEs. [ 82 ]…”

“…is thanks to the strong H-bond interactions among eutectic composition and gel/polymer network, further suppressing water reactivity and reinforcing the stability of SSEs. [82] Interestingly, Cai et al recently revealed a water-salt oligomers electrolytes (WSOEs) that formed without adding additional monomers, the super-solubility (up to 75 m) of ZnCl 2 /ZnBr 2 /Zn(OAc) 2 aqueous electrolyte is attributed to the formation of acetatecapped bridging via Br − /Cl − …H and Br − /Cl − /O…Zn 2+ interactions. As a result, this super-soluble electrolyte exhibits a polymer-like glass transition temperature around −70 °C and enables high-performance with a reversible capacity (605.7 mAh g −1 ) and a CE of 98.07% (Figure 8a).…”

Toward High Energy Density Aqueous Zinc‐Ion Batteries: Recent Progress and Future Perspectives

“…[27][28][29] Table 1 shows the reported electrolyte designs to improve the narrow ESW of aqueous electrolytes. [30][31][32][33][34][35][36][37][38][39][40][41] Herein, we discuss strategies to suppress water decomposition for the broad ESW of aqueous electrolytes and high operating voltage in ZIBs, including the optimization of pH, utilization of bication electrolytes, introduction of small-dipole additives, and design of polymer-supported gel electrolytes.…”

“…The poly(ethylene glycol) dimethacrylate (PEGDM)-based structure assisted the formation of gel electrolytes with a strong hydrogen bonding. [39] The designed HGE exhibited numerous advantages for use in aqueous ZIBs, such as low manufacturing cost, safety, mechanical flexibility, the high solubility of Zn(ClO 4 ) 2 salt, the utilization of adiponitrile (AND) as an organic solvent molecule for the large ESW, and electrochemical/thermal stability. In particular, the OER potential shifted from 2.53 to 2.63 V (vs. Zn/ Zn 2 + ) in the optimized 2 M Zn(ClO 4 ) 2 -based HGE electrolyte (Figure 3b).…”