Rational Design of Sulfonamide‐Based Additive Enables Stable Solid Electrolyte Interphase for Reversible Zn Metal Anode

Abstract

The solid electrolyte interphase (SEI)-forming additives strategy is of great significance for improving the cycle stability of zinc (Zn) anodes. Although various additives have been reported, the relationship between their molecular structures and SEI chemistries is poorly understood. Herein, a molecular design principle for sulfonamide-containing additives that endow Zn anodes with a robust SEI layer is proposed. The incorporation of the benzene ring and amino group (−NH 2 ) leads to high adsorption energy, low lowest unoccupied molecular orbital lowest unoccupied molecular orbital (LUMO), and a small highest occupied molecular orbital-LUMO (HOMO-LUMO) gap, facilitating the reduction process of sulfanilamide (SA) additives. Coupled with SA/ZnSO 4 electrolytes, Zn|Zn symmetric cells deliver an ultralong cycle life of 4800 h (200 days) at 2 mA cm −2 and 2 mAh cm −2 . Additionally, a high cumulative plated capacity (CPC) of 6000 mAh cm −2 and 2700 mAh cm −2 is also achieved at a capacity per cycle of 10 mAh cm −2 and 30 mAh cm −2 , respectively. More importantly, the versatility of SA additives is also demonstrated in Zn-V 2 O 5 , Zn-I 2 , and Zn-MnO 2 full cells at a low N/P ratio (the theoretical capacity ratio between the negative and positive electrode) of 5.3, 8.3, and 4.5, respectively. This molecular structure strategy provides a promising path to develop effective SEI-forming additives.

Dextran: A Multifunctional and Universal Electrolyte Additive for Aqueous Zn Ion Batteries

“…[71] Thus, we assembled Zn//V 2 O 5 coin cells with a low N/P ratio of 2.18, comparable to the state-of-the-art ZIBs reported in recent studies, and tested them under similar conditions (see the result comparison in Table S1, Supporting Information). [19,72] The cell with the D-ZF electrolyte can be stably cycled for 138 cycles at the current density of 1 A g -1 (Figure 5d). In contrast, the specific capacity of the cell with the ZF electrolyte fluctuates significantly and decreases dramatically after only 37 cycles.…”

Selection criteria for electrical double layer structure regulators enabling stable Zn metal anodes

“…3a, Zn|Zn symmetric cells delivered a larger charge transfer resistance in the Sul/ZnSO 4 electrolyte in comparison with that in the ZnSO 4 electrolyte, suggesting the occupation of sulfolane in the EDL structure. 47 Moreover, a strong characteristic peak corresponding to the sulfone group was detected in the S 2p spectra of Zn anodes immersed in deionized water with 0.5 vol% sulfolane, demonstrating the adsorption of sulfolane on the Zn surface (Fig. S12, ESI †).…”

“…S4, ESI †). 47 The first-principles calculation was further performed to theoretically confirm the unique adsorption behavior of these additives. Fig.…”

Size-Complementary, High-Concentration Zincophilic Solute Molecules for Wide-Temperature-Range Aqueous Zinc Metal Batteries

“…To confirm the SEI-forming ability of the zincophilic additives, the highest occupied molecular orbitals (HOMO) and lowest unoccupied molecular orbitals (LUMO) were calculated by DFT. As shown in Figure c, the LUMO energy levels of the zincophilic coordination compounds (−13.273, −13.078, −13.123, and −12.635 eV for silk amino acids and −13.127 eV for acetamide) are significantly smaller than those of the anions (−8.385 and −8.733 eV), endowing them with higher electron affinity and allowing them to be reduced more easily. , Furthermore, the silk amino acids and acetamide had a higher adsorption energy than the anions and a smaller HOMO–LUMO gap, facilitating the reduction process at the Zn-anode interface and the formation of a stable nitride layer (Figures d and S21).…”