Ti₃C₂T Filled in EMIMBF₄ Semi-Solid Polymer Electrolytes for the Zinc-Metal Battery

Zinc-ion batteries (ZIBs) are promising candidates for safe energy storage applications. However, undesirable parasitic reactions such as dendrite growth, gas evaluation, anode corrosion, and structural damage to the cathode under an acidic microenvironment severely affected cell performance. To resolve these issues, an MXene entrapped in an ionic liquid semi-solid gel polymer electrolyte (GPE) composite was explored. The molecular-level mixing of poly(vinylidene fluoride-co-hexafluoropropylene) (PVHF), zinc trifluoromethanesulfonate (Zn(OTF)₂), 1-ethyl-3-methylimidazolium tetrafluoroborate (EMIBF₄) ionic liquid, and Ti₃C₂T MXene provided a controlled Zn²⁺ shuttle toward the anode/cathode. Ti₃C₂T/EMIBF₄/Zn(OTF)₂/PVHF exhibited a breaking strength of 0.36 MPa with an associated extension of 23%. The Zn//Ti₃C₂T/EMIBF₄/Zn(OTF)₂/PVHF//Zn symmetric cell with continuous zinc plating/stripping exhibited excellent Zn²⁺ ion mobility toward the anode and cathode without undesired reactions. This was confirmed by post-mortem analysis after a symmetric cell compatibility test. The as-prepared GPE with a Na₃V₂(PO₄)₃ (NVP) cathode exhibited a high chemical diffusion coefficient of 1.14 × 10^-7. It also showed an outstanding reversible capacity of 89 mAh g^-1 at C/10 with an average discharge plateau voltage of 1.45 V, cycle durability, and controlled self-discharge. These results suggested that the Zn²⁺ ions in the Ti₃C₂T/EMIBF₄/Zn(OTF)₂/PVHF composite are reversibly labile in the anode and cathode directions.