A shear-thickening colloidal electrolyte for aqueous zinc-ion batteries with resistance on impact

Abstract

A conventional aqueous electrolyte is a crucial component of zinc-ion batteries providing an ion conductive medium. However, the monofunction of a liquid electrolyte cannot bear any external load. With regard to applications in electric vehicles and stationary energy storage devices, complicated battery packing materials are required to improve the mechanical properties, resulting in reduced energy or power densities from the perspective of the entire device. In this work, an electrolyte suspension combining both fluid-like and solid-like performances was developed for rechargeable zinc-ion batteries. Cornstarch water suspension is utilized in the electrolyte design forming a shear-thickening electrolyte with impact resistance ability. The formed electrolyte becomes rigid at a high shear rate. In other words, under a sudden impact, a battery with this shear-thickening electrolyte could offer additional load bearing avoiding short-circuiting and improving safety. Although an additional functionality, namely impact resistance, was added to the electrolyte, the as-prepared electrolyte still performs with comparable electrochemical performances for which it exhibits a superior ionic conductivity of 3.9 × 10⁻³ S cm⁻¹ and Zn²⁺ transference number. This electrolyte even suppresses side-effects on the zinc anode, exhibiting a lower voltage gap in the symmetric cell compared to the aqueous electrolyte. The integrated full cell also delivered a specific capacity of 255 mA h g⁻¹ with commercial MnO₂ as the cathode at a current density of 0.1 A g⁻¹.