1D/2D heterostructure induced built-in electric field accelerate the reaction kinetics of MnO2/MXene paper-like film for advanced flexible zinc-ion batteries

Abstract

Paper-like flexible electrode plays a critical importance role in booming the development of flexible energy storage devices. One-dimensional manganese dioxide (1D MnO2) shows immense advantage in flexible zinc-ion batteries (FZIBs) on account of renowned tunnel crystal structure and high operating voltage. However, inherent inferior electrical conductivity and sluggish reaction kinetics seriously hinder the practical application of FZIBs, resulting in unsatisfactory rate capability and cycle performance. Herein, 1D/2D MnO2/MXene-5 heterostructure materials were constructed by electrostatic self-assembly, which were then prepared into paper-like membrane with high energy storage active substance ratio (95.2 %) towards high capacity and ultrastable FZIBs. The built-in electric field induced by the heterostructure accelerates the electron transfer, reduces the charge transfer resistance and promotes ion diffusion, enabling the 1D/2D phase collaboration to improve the zinc ion storage of the paper-like electrode. The design achieves a high total specific capacity (based on the total cathode mass) of 314.7 mAh g−1 at 0.1 A g−1 and ultrastable of 8000 cycles at 5 A g−1 with a retention of 81.1 %. Remarkably, quasi-solid-state FZIBs with MnO2/MXene-5 membrane can deliver an outstanding reversible capacity of 273.5 mAh g−1 at 0.1 A g−1 and maintain 500 cycles at 1 A g−1 across various bending angles without decay, demonstrating excellent stability. This work provides a novel approach for the targeted design of self-standing flexible electrodes.