Customizing Ion Transport by Anionphilic Nanofiber‐Polymer Electrolyte for Stable Zinc Metal Batteries

ABSTRACT The formation of zinc metal dendrites and electrolyte side reactions in rechargeable zinc‐metal batteries (RZMBs) is closely related to ion transport within the electrolyte. In salt‐doped polymer electrolytes, polymer polarity can be used to control ion transport. Here, we report an anionphilic polymer electrolyte with positive relative anion affinity. By introducing a polymer backbone with weak adsorption of cations and another polymer chain with strong adsorption of anions, weakened the cation‐dipole coordination for Zn 2+ , which enables promote the dissociation of salt and restrict the migration of anions. The polymer electrolyte‐design concept is demonstrated by using polyacrylamide and aramid nanofibers. Prepared anionphilic polymer hydrogel electrolytes effectively inhibited the hydrogen evolution reaction, forming conformal and adherent inorganic‐rich solid electrolyte interphase. The anionphilic polymer electrolytes also exhibit high Zn 2+ transference number (0.71), enabling Zn 0.25 V 2 O 5 ǀǀZn (30 µm) pouch cells (4.9 mAh cm −2 ) to achieve high reversibility over 270 cycles.