Ti 3 C 2 T x Filled in EMIMBF 4 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 (EMIBF 4 ) ionic liquid, and Ti 3 C 2 T x MXene provided a controlled Zn 2+ shuttle toward the anode/cathode. Ti 3 C 2 T x /EMIBF 4 /Zn(OTF) 2 /PVHF exhibited a breaking strength of 0.36 MPa with an associated extension of 23%. The Zn//Ti 3 C 2 T x /EMIBF 4 /Zn(OTF) 2 /PVHF//Zn symmetric cell with continuous zinc plating/stripping exhibited excellent Zn 2+ 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 Na 3 V 2 (PO 4 ) 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 Zn 2+ ions in the Ti 3 C 2 T x /EMIBF 4 /Zn(OTF) 2 /PVHF composite are reversibly labile in the anode and cathode directions.