Ionic conductive bio-based composite aerogels

In the realm of energy transition, significant advancements are essential on the improvement of energy storage performance as well as in sustainability and safety. Aerogels are lightweight materials that can be endowed with mechanical strength, thermal insulation capability, and fire resistance. These characteristics make them promising for electrochemical devices such as composite polymer electrolytes (CPE). Silica-based aerogels have been used as scaffolds for solid polymer electrolytes (SPE). In these applications, the aerogel not only provides structural support but also creates additional conduction channels that improve ionic conductivity (IC). In this work, we present a bio-based aerogel composed of gelatin, montmorillonite clay, and tannic acid, synthesized using water as a solvent. By employing an ice templating strategy,we achieved a 1D pore orientation, which provides more direct conduction pathways. This aerogel exhibits an axially oriented honeycomb porous structure with high porosity (92.9 ± 0.1%) and low density (0.130 ± 0.002 g/cm³). It is also categorized as a self-extinguishing material. This aerogel was infiltrated with a SPE consisting of Polyethylene glycol (PEG) and Lithium bis (trifluoromethanesulfonyl) imide (LiTFSI). With partial pore coverage, we achieved IC at room temperature on the order of 2 × 10-7 S/cm. This led to promising results, resulting in a porous (76%) ionic conductive aerogel that opens new perspectives. It enables the creation of a low-density solid electrolyte, which can increase the specific capacity of the final device. Alternatively, it can serve as an active, fire resistant, scaffold for a liquid or gel electrolyte, enhancing and maximizing IC.