Functional Ultrathin Separators Proactively Stabilizing Zinc Anodes for Zinc‐Based Energy Storage

Abstract

Ultrathin separators are indispensable to high‐energy‐density zinc‐ion batteries (ZIBs), but their easy failure caused by zinc dendrites poses a great challenge. Herein, 23 µm‐thick functional ultrathin separators (FUSs), realizing superb electrochemical stability of zinc anodes and outstanding long‐term durability of ultrathin separators, are reported. In the FUSs, an ultrathin but mechanically strong nanoporous membrane substrate benefits fast and flux‐homogenized Zn2+ transport, while a metal–organic framework (MOF)‐derived C/Cu nanocomposite decoration layer provides rich low‐barrier zinc nucleation sites, thereby synergistically stabilizing zinc anodes to inhibit zinc dendrites and dendrite‐caused separator failure. Investigation of the zinc affinity of the MOF‐derived C/Cu nanocomposites unravels the high zincophilicity of heteroatom‐containing C/Cu interfaces. Zinc anodes coupled with the FUSs present superior electrochemical stability, whose operation lifetime exceeds 2000 h at 1 mA cm−2 and 600 h at 10 mA cm−2, 40–50 times longer than that of the zinc anodes using glass‐fiber separators. The reliability of the FUSs in ZIBs and zinc‐ion hybrid supercapacitors is also validated. This work proposes a new strategy to stabilize zinc anodes and provides theoretical guidance in developing ultrathin separators for high‐energy‐density zinc‐based energy storage.

Activating Gel Polymer Electrolyte Based Zinc-Ion Conduction with Filler-Integration for Advanced Zinc Batteries

“…Meanwhile, SiO and TiO 2 inorganic-filler derived gel as well displayed good stability to zinc anode in Figure S9, and the corresponding ionic conductivity still revealed a considerable elevation in comparison with pure gel at a wide temperature range, as provided in Figure S10. The accessible 3D diffusion process along with low active energy for Zn#20 validated the improved kinetics in Figure S11. − Moreover, the ZnO#20-based cell as well performed the steady plating/stripping potential at −20 °C (Figure S12). To sum up, ZnO filler in the PVA gel polymer better extended the symmetric cell cycling life arising from the better stress strength and improved ion conductivity.…”

In‐Situ Integration of a Hydrophobic and Fast‐Zn2+‐Conductive Inorganic Interphase to Stabilize Zn Metal Anodes

“…The Zn 2+ transference number ( t $${{_{{\rm Zn}{^{2+}}}}}$$ ) is measured to evaluate the Zn 2+ diffusion ability of ZnHCF. Generally, a low t $${{_{{\rm Zn}{^{2+}}}}}$$ would induce a large Zn 2+ concentration gradient at the electrode/electrolyte interface and aggravate dendrites propagation [4d, 6a, 17] . Based on the chronoamperometry and electrochemical impedance spectroscopy (EIS) tests (Figures 5d and S20), [7a, 20b] the HB‐ZnHCF exhibits an ultrahigh t $${{_{{\rm Zn}{^{2+}}}}}$$ of 0.86, which dramatically outperforms the bare Zn ( t $${{_{{\rm Zn}{^{2+}}}}}$$ ≈0.35) and HL‐ZnHCF@Zn ( t $${{_{{\rm Zn}{^{2+}}}}}$$ ≈0.56).…”

Low-Cost Electrolyte Additive Enables an Ultra-stable and Dendrite-Free Zn Anode

“…Many strategies have been proposed to eliminate the zinc dendrites and side reactions, such as modifying current collectors to encourage Zn 2+ nucleation, − constructing functional zinc layers on the zinc surface to modify the interfacial electric field, , designing a functionalized separator to protect the zinc anode, and optimizing the composition of the electrolyte to modify Zn 2+ solvation shells. − Although these methods can suppress related problems to a certain extent and prolong the cycle life of new metal anodes, the operation methods are complicated and cannot be applied on a large scale. The scheme of the electrolyte additive has been widely studied because of its simple operation and obvious effect.…”