Three-Dimensional Porous Spongy Ti3C2Tx MXene/Polyvinyl Alcohol/Agar Gel Electrolyte with High Ionic Conductivity Enables Highly Reversible Zinc-Ion Batteries

Abstract

Gel electrolyte is one of the key components of flexible energy storage devices. The construction of a three-dimensional (3D) porous gel electrolyte with high ionic conductivity is a very effective strategy to improve the performance of zinc-ion batteries (ZIBs). Herein, porous polyvinyl alcohol-Agar-sodium dodecyl sulfate-MXene-dimethyl sulfoxide (DMSO) (denoted as PVA-Agar-SDS-MXene-DMSO (PASMD)) gel electrolyte with double network is prepared through one-pot method by adding two-dimensional (2D) MXene to improve its ionic conductivity and DMSO to increase its low-temperature resistance. Meanwhile, the as-prepared PASMD gel electrolyte with a high ionic conductivity of 50.63 mS cm⁻¹ realizes the gradient induction and redistribution of Zn²⁺, which drives oriented Zn (002) plane deposition of Zn²⁺ and then achieves uniform Zn deposition and dendrite-free anode. The specific capacity of the assembled flexible Zn//PASMD//β-MnO₂ battery can reach 205 mAh g⁻¹ at 0.2 A g⁻¹. It also exhibits good performance both at room temperature and −20 °C with stable cyclic stability for more than 1000 h. After 1000 cycles at 1 A g⁻¹, the assembled flexible battery stabilizes at 67 mAh g⁻¹. This work provides an alternative pathway for the development of high-performance gel electrolytes with low-temperature resistance and high-ionic conductivity for flexible ZIBs.