ENABLING POLY ETHER ETHER KETONE AS A SOLID POLYMER ELECTROLYTE FOR STRUCTURAL BATTERY COMPOSITES

To advance the state of structural battery composites, more mechanically robust polymeric materials must be investigated for use as the ionically conductive electrolyte. Currently, the matrices being utilized in solid polymer electrolytes lack mechanical strength, and are often gels, due to their amorphous structure offering increased lithium-ion conductivity. To address the need for more robust, semicrystalline polymer matrices, poly ether ether ketone (PEEK) was selected as a candidate that would offer both ionic conductivity and mechanical reinforcement in these novel multifunctional composite structures. Through a series of functionalization procedures, specifically sulfonation and lithiation of the polymer chains, the PEEK exhibits ionic conductivity and an amorphous microstructure. However, to maintain the structural characteristics required of the matrix, careful functionalization is used to tailor the PEEK electrolytes and strike a balance between the two inversely related properties (ion conductivity and crystallinity). It was found that selective adjusting of the morphology of the solid electrolyte successfully enables the two properties that are most important for this multifunctional application. The discoveries presented from this work provide a foundation to continue progress on thermoplastic structural battery composites.