Designing Antifreeze Electrolytes with Colloid‐Like Structures for High‐Rate Performance in Aqueous Zinc‐Ion Batteries

This study introduces konjac glucomannan (KGM) as a dual-functional additive for aqueous zinc-ion batteries. KGM disrupts the hydrogen bond network and acts as a Zn²⁺ coordinator, forming a colloid-like electrolyte. This innovative structure enhances antifreeze performance and cycling stability, enabling long-term operation under low temperatures and high-rate conditions.

Abstract

Optimizing the electrolyte configuration is an effective strategy to enhance the cycle life of aqueous zinc-ion batteries (AZIBs). A critical challenge in electrolyte development involves improving the antifreeze characteristics without compromising high-rate performance for the AZIBs. This study selects the polymer polysaccharide konjac glucomannan (KGM) as an electrolyte additive, aiming to utilize its naturally formed stable colloidal system in aqueous solution, which exhibits superior rheological properties. This system can effectively balance the antifreeze performance of the electrolyte with the performance requirements of the cell under high-rate charge–discharge conditions, thereby enhancing the overall performance of the cell. Therefore, the zinc anode exhibits stable cycling for 1250 h at 25 °C under conditions of 7 mA cm⁻² and 3.5 mAh cm⁻². At -10 °C, stable cycling is sustained for over 800 h at 7 mA cm⁻² and 1 mAh cm⁻². In full cells, the cell delivers a discharge capacity of 77.9 mAh g⁻¹ after 7500 cycles at a current density of 15 A g⁻¹ at 25 °C. Even at -10 °C, the cell delivers a discharge capacity of 102.7 mAh g⁻¹ after 660 cycles at 3 A g⁻¹. KGM offers a cost-effective, environmentally friendly solution to improve AZIBs' reliability and antifreeze capabilities.