Designing Hybrid Inorganic-Organic Materials By Utilizing Sol-Gel Chemistry for Batteries and Energy Storage

The focus of this work is to investigate the morphology, physical properties, and ion transport of tetraethyl orthosilicate (TEOS)-titanium isopropoxide (TIP)-polymer hybrid membranes depending on different composition. TEOS and TIP are two precursors used in sol-gel process to prepare Si-Ti mixed materials as the inorganic component. Penta block copolymer (PBC) is used as the organic component, which is poly(t-butyl styrene-b-ethylene-co-propylene-b-styrene-co-styrenesulfonate-b-ethylene-co-propylene-b-t-butyl styrene). Unlike the previous work done by soaking membrane in inorganic sol or mixing polymer with inorganic particles, TEOS-TIP-PBC hybrid membranes were prepared from homogenous inorganic-organic solutions by controlling different TEOS: TIP molar ratio and different concentration of inorganic components in hybrid membranes. Contact angle data by Kruss DSA 100 surface analyser, water uptake, proton conductivity by Autolab potentiostat, mechanical properties by dynamic mechanical analysis (DMA), and thermal stability by thermal gravity analysis (TGA) were investigated and highly affected by the composition. The most interesting results we found is that the proton conductivity of hybrid membranes with both acid and salt form was significantly increased compared with the pure PBC membranes, which opens the potential that these novel hybrid materials can be used in fuel cells, lithium-ion battery, or vanadium redox flow battery. In the future work, other polymers with sulfonate group, such as Nafion, will be included to prepare hybrid membranes. Moreover, other characterizations and applications, such as transmission electron microscopy (TEM), small angle x-ray scattering (SAXS), methanol permeability, and single cell performance of these hybrid membranes will be further investigated.