Urethane-modified porous cyclodextrin polymer enables high-performance solid-state zinc-ion batteries

Solid polymer electrolytes (SPEs) are deemed as an effective approach to mitigate dendrite formation and inhibit side reaction of Zn anode for zinc-ion batteries, but face some hurdles from sluggish Zn²⁺ migration and poor ionic conductivity. In this study, a urethane-modified porous cyclodextrin polymer (UR-CDP) is developed and incorporated into poly (vinylidene fluoride) matrix to fabricate solid polymer electrolyte (UR-CDP/PVDF). The porous architecture of UR-CDP offers ion-diffusion channels, the cavity of cyclodextrin can effectively anchor anions, and urethane groups exhibit strong interactions with zinc ions, which collectively promote the orderly Zn²⁺ transport. Consequently, the UR-CDP/PVDF electrolyte achieves an excellent ionic conductivity of 4.05 × 10^-4 S cm^-1 and an exceptional Zn²⁺ transference number of 0.80. Moreover, the Zn symmetric battery assembled with UR-CDP/PVDF demonstrates a stable cycle life of 3960 h at a current density of 2 mA cm^-2. Additionally, the assembled Zn//NH₄V₄O₁₀ full battery can operate for 3200 cycles at 2 A g^-1 without significant capacity decay, which is attributed to the effective inhibition of vanadium dissolution by the UR-CDP/PVDF electrolyte. This work proposes a multi-functional cyclodextrin polymer modification strategy to address the current challenges confronted by Zn anode and vanadium-based cathode, offering a facile route toward high-performance solid-state zinc-ion batteries.