Here, the authors design a “beyond aqueous” colloidal electrolyte with ultralow salt concentration and inherent low freezing point and investigate its colloidal behaviors and underlying mechanistic principles to stabilize cryogenic Zn metal battery.
However, capacity loss and low Coulombic efficiency resulting from polyiodide cross-over hinder the grid-level battery performance. Here, we develop colloidal chemistry for iodine-starch catholytes, endowing enlarged-sized active materials by strong chemisorption-induced colloidal aggregation.
The colloidal IS-based Zn-IS FBs with polypropylene (PP) membranes as LPPM could deliver superior performance of cycling stability for 350 cycles at high current density. In addition, due to the strong chemisorption between starch and iodine redox, the as-developed colloidal IS systems remained stable.
For the I x− permeability under high temperature of 50 °C (Supplementary Figs. 42 and 43), the colloidal starch could strongly confine the polyiodides by forming a colloidal aggregation featuring low I x− permeability to impede the cross-over issue even at a severe condition of high temperature.
During the battery cycle process, factors such as the electric field effect and its constantly changing direction, ion concentration’s variations at the interface, and bulk phase of electrolyte can significantly influence both the stable state and motion behavior of colloidal particles.
The colloidal electrolytes, as one of the emerging electrolytes, will arise gushing research interest due to their complex colloidal behaviors and mechanistic actions at different conditions (aqueous/nonaqueous solvents, salt concentrations etc.).