Ultrahigh coulombic efficiency and long-life aqueous Zn anodes enabled by electrolyte additive of acetonitrile

“Water‐in‐Deep Eutectic Solvent” Electrolytes for High‐Performance Aqueous Zn‐Ion Batteries

“…Benefiting from the compatibility with Zn anodes, a neutral or mild acidic aqueous electrolyte (such as Zn(CF 3 SO 3 ) 2 and ZnSO 4 dilute solutions) is preferred for ZIBs, but the electrolytes often suffer from poor CEs and narrow electrochemical stability window (ESW). [ 11–17 ] The “water‐in‐salt” electrolyte and the ionic liquid are feasible choices to gain the satisfying electrochemical performance by forming the special Zn 2+ ‐solvation sheath. [ 18–21 ] Unfortunately, the salts (such as Zn(TFSI) 2 and Zn(BF 4 ) 2 ) with high price in these systems especially in ionic liquid impede their practical application.…”

Strategies of regulating Zn2+solvation structures for dendrite-free and side reaction-suppressed zinc-ion batteries

“…Except the alcohol additives, other organic solvent additives such as acetonitrile (AN), 184–188 dimethyl carbonate (DMC), 189 diethyl ether, 190 1,4-dioxane (DX), 191 1,2-dimethoxy ethane (DME), 192 trimethyl phosphate (TMP), 193,194 and dimethyl sulfoxide (DMSO) 79,80,195–197 have been widely reported. Acetonitrile (AN), which is commonly known to cooperate with Zn 2+ , 198,199 is recognized as a suitable electrolyte additive to regulate the cooperation environment of Zn 2+ .…”

“…The electrochemical performances of zinc anode with various organic solvent additives are summarized in Table 2. 17,79,170,174,176–178,184,186–195,202–205 Generally, these organic solvent additives always show excellent solubility in water and can preferentially solvate with Zn 2+ ions. Besides, they have a strong interaction with H 2 O, which can reduce the activity of free H 2 O molecules.…”

Insight on Organic Molecules in Aqueous Zn‐Ion Batteries with an Emphasis on the Zn Anode Regulation

“…Their roles in AZIB depend on their relative content and interaction with Zn ions, as displayed in Table 3. [ 29,31,70,93–98 ] With a small amount (e.g., 2 vol% for diethyl ether), the organic solvent only covers on the protrusion tips and displays a shielding effect. [ 31 ] However, to further raise the efficacy of Zn anode, various types of solvents were utilized and the amount was optimized, for the commonly used alcohols (e.g., methanol, ethylene glycol, and glycerol), [ 29,97,98 ] the optimal volume ratio was found to be around ≈50%.…”