Unraveling the Solvation Structure and Electrolyte Interface through Carbonyl Chemistry for Durable and Dendrite‐Free Zn Anode

Abstract

Aqueous Zn ion batteries are appealing systems owing to their safety, low cost, and environmental friendliness; however, their practical applicability is impeded by the growth of Zn dendrites and side reactions. Herein, a dual‐functional electrolyte additive, namely acetylacetone (AT) is utilized for the simultaneous regulation of the solventized structure and anode–electrolyte interface (AEI) to achieve a durable, dendrite‐free Zn anode. Theoretical calculations and experimental characterizations reveal that the AT molecule can be adsorbed onto Zn metal surface to reconstruct the AEI and allow for the primordial desolvation of [Zn(H2O)6]2+ at locations away from the surface of the Zn anode during deposition, which is attributed to the strong polarity of the carbonyl functional group. In addition, the two carbonyls of AT can replace two H2O molecules in the primary solventized structure of Zn2+ to reduce the number of active H2O molecules, efficiently suppressing Zn dendrite growth and detrimental reactions. As a proof of concept, a Zn//Cu cell is constructed in ZnSO4 containing 3 vol.% AT electrolyte, delivering stable cycling over 1800 cycles while maintaining a high Coulombic efficiency of 99.74%. This study provides a practical approach for inhibiting dendrite growth and side reactions by harnessing carbonyl chemistry.

Bio-inspired hydroxyl-rich electrolyte additive for highly reversible aqueous Zn-ion batteries with strong coordination chemistry

“…With the import of l -Aa, the cycling life of Zn//Zn symmetric cells at high current density achieves a larger improvement compared with previous results with different additives. 13,14,28,34,54,57–64 The findings presented herein provide compelling evidence that the incorporation of l -Aa can yield a substantial development in the electrochemical reversibility of Zn anodes.…”

“…Among these strategies, electrolyte additives feature low cost and high operability and have drawn much attention in recent years, 31–33 which have a crucial effect on regulating the zinc coordination chemistry and are deemed as an effective pathway to attain superior performance ZIBs. The reported working mechanisms of electrolyte additives mainly include constructing water-poor interface, 34,35 reducing solvation effect, 36,37 and forming solid electrolyte interface. 38,39 Recently, various organic solvents were employed as the electrolyte additives to suppress the decomposition of H 2 O molecules and broaden the operational temperature range via the stronger interaction between H 2 O and the polar functional groups of the organic solvents, such as ethylene glycol, 40 dimethyl sulfoxide, 41 and methanol.…”

Zincophilic Anionic Hydrogel Electrolyte with Interfacial Specific Adsorption of Solvation Structures for Durable Zinc Ion Hybrid Supercapacitors

“…[36] The obtained results suggested that the sulfate group in (OSO 3 R) − with a certain electron-donating capability can coordinate with Zn 2+ , which is able to compete with the bound D 2 O molecules and tip the hydrated solvation balance of Zn 2+ . [37] In contrast, a negligible shift (4.717 ppm) of the 1 H peak can be observed after dissolving the SDS into the pure D 2 O, implying a weak interaction between the SDS and water molecules.…”

Trade-off between H2O-rich and H2O-poor electric double layers enables highly reversible Zn anodes in aqueous Zn-ion batteries

“…As previous studies have reported, the size of nucleated particles could become smaller when the nucleation overpotential increases, and the fine-grained nucleation facilitates the homogeneous Zn deposition, indicating that the deposition behavior can be optimized by the APM. 26,39,40 Meanwhile, the morphology of Zn deposited on the Cu metal in different electrolytes were observed to further investigate the influence of the H 2 O-poor EDL, and the digital photograph shows that the nucleation and growth of Zn is mainly in the local area of the Cu surface in 2 M ZnSO 4 ; the deposition morphology has no obvious improvement in 2 M ZnSO 4 + 0.1 mM APM (Fig. S12a and b, ESI†).…”