Lu, QingyeHassan, Md Mehadi2024-08-302024-08-302024-08-29Hassan, M. (2024). Controlling nanoarchitecture of biopolymer-based flexible electrolyte membranes for solid-state lithium-ion and sodium-ion battery (Doctoral thesis, University of Calgary, Calgary, Canada). Retrieved from https://prism.ucalgary.ca.https://hdl.handle.net/1880/119562This thesis focuses on utilizing naturally abundant animal and plant-based biopolymers with diverse functionalities (e.g., chitosan (CH), cellulose acetate (CA), and polylactic acid (PLA)) for developing solid-state electrolyte (SSE) membranes and their applications in solid-state sodium-ion (ss-SIBs) and lithium-ion batteries (ss-LIBs). The nanoarchitecture of these membranes with porous morphology, is finely tuned and controlled using additive materials and facile fabrication techniques such as solution casting and electrospinning. In the first study, with a facile and cost-effective solution-casting technique, we fabricated a flexible, wearable, and thin film (~0.08 mm) solid polymer electrolyte membrane (SPEM) consisting of 2D-HGO, lithium bis(trifluromethanesulfonyl)imide (LiTFSI) salt, polyvinylpyrrolidone polymer binder, nano-SiO2, and CH biopolymer. In the composite SPEM, a unique arrangement of coherently aligned 2D porous HGO nanosheets was observed within the host CH polymer matrix, facilitating the creation of unique 3D-ion transfer pathways and exhibited impressive ionic conductivity of 2.76x10-3 Scm-1 at room temperature (RT= 23 °C). The second study utilized a distinct and versatile humidity-induced electrospinning method to fabricate porous fiber membranes composed of PLA biopolymer. The impact of porous morphology and the degree of alignment of the polymer fibers on the mechanical properties, surface roughness, wettability and ion conduction performance were evaluated using the electrospun membrane. In the third and fourth studies, a simple combination of electrospinning and solution casting was utilized to fabricate mechanically robust, flexible, free-standing, and thin-film CA and CH biopolymer-based randomly distributed electrospun composite electrolyte (ECE—third study) and aligned ECE (AECE—fourth study), respectively, where CA electrospinning fiber mat was casted by the CH and NaPF6 salt solution. RT Na+ conductivity of nano-porous AECE (4.12x10-4 Scm-1) demonstrated improved performance compared to that of randomly distributed nano-porous electrospun ECE (1.04x10-4 Scm-1). Further, RT specific discharge capacity of 98.1 mAhg-1 was attained at a 0.1 C rate, with a capacity retention of 93.4% over 120 charge-discharge cycles in the ECE-based hybrid full-cell assembly. Overall, the novel porous microstructure engineering strategies of nanocomposite SSE membranes, along with their comprehensive characterization and battery application findings, offer valuable insides for future designs of eco-friendly, flexible and wearable solid electrolytes for ss-LIBs and ss-SIBs.enUniversity of Calgary graduate students retain copyright ownership and moral rights for their thesis. You may use this material in any way that is permitted by the Copyright Act or through licensing that has been assigned to the document. For uses that are not allowable under copyright legislation or licensing, you are required to seek permission.BiopolymersSolid Polymer ElectrolyteChitosanCellulose acetateElectrospun fiberSolution-castingLi-ion BatteryNa-ion BatteryEngineering--ChemicalEnergyMaterials Sciencedoctoral thesis