An anti-aging polymer electrolyte for flexible rechargeable zinc-ion batteries

Abstract

Polymer electrolytes have been extensively applied in zinc-ion batteries, especially those based on hydrogels; however, the densification of the hydrogel electrolytes during cycling affects the durability, resulting in capacity attenuation. It is revealed in this work that the surface electrical resistance of hydrogels is particularly affected by the aging effect. Hence, an adhesive bonding solid polymer electrolyte (ABSPE) for zinc-ion batteries was developed exhibiting significantly enhanced anti-aging properties, where the surface resistance remains constant for over 200 hours, twice that of conventional hydrogel electrolytes. For the hydrogel electrolyte, the surface resistance only remains constant for less than 100 hours which is half of the time achieved by the ABSPE. The ionic conductivity increases with plasticizer loading, reaching 3.77 × 10⁻⁴ S cm⁻¹. The kinetic mechanism probed in this work revealed a diffusion-controlled mechanism for Zn/ABSPE/β-MnO₂ instead of a capacitive dominated process in the hydrogel electrolyte. In addition, a flexible device was fabricated using a carbon fibre-reinforced polymer composite; this device showed superior power supply performance even under twisting, cutting and bending conditions.