Regulating dielectricity of a polymer electrolyte to promote cation mobility for high-performance solid zinc hybrid batteries

Solid polymer electrolytes (SPEs) offer the advantages of suppressing uncontrollable dendrite formation and the hydrogen evolution reaction (HER) at the Zn metal anode of Zn-based batteries, providing good electrochemical stability and a high working voltage. However, the low ionic conductivity of SPEs does not meet the performance demands for the high-power density of Zn-based batteries. In this study, we first regulated the high dielectric constant (ε_r) and the ferroelectric domain of the host polymer frameworks to promote salt dissociation and ion transportation, thereby enhancing the ionic conductivity and cation mobility of SPEs. Specifically, a high ionic conductivity of up to 1.07 mS cm⁻¹ was achieved by utilizing the SPE based on poly(vinylidene fluoride-co-trifluoroethylene-co-chlorotrifluoroethylene) [(PVDF-TrFE-CTFE)] (referred to as PVTF). The as-fabricated symmetric Zn‖Zn batteries based on the PVTF SPE could exhibit splendid cycling stability for more than 210 days (>5000 h). When paired with a cathode, the developed solid rechargeable Zn hybrid batteries can operate at high power up to a 10C-rate and exhibit stable cycling for 1000 cycles at 2C. This work illustrates that regulating the ferroelectric domain with a higher ε_r of SPEs is an effective strategy to enhance the ionic conductivity and transport ability, showing great prospects for their practical application in Zn-based batteries. © 2024 The Royal Society of Chemistry.