Polyethylene Glycol-Based Solid Polymer Electrolytes: Encapsulation Materials with Excellent Anodic Bonding Performance

Herein, we report the design and synthesis of polyethylene glycol (PEG)-based solid polymer electrolytes (PEG-LiClO4-SiO2) by mechanical alloying, using the obtained composites asencapsulation materials for microelectromechanical system (MEMS) production by anodic bonding. The above materials are characterized by a number of analytical techniques (X-ray diffraction, differential scanning calorimetry, scanning electron microscopy, and small-angle X-ray scattering) which reveal that Li salt addition significantly influences the performance of these complex systems. We demonstrate that increased Li salt loadings can effectively inhibit PEG crystallization and increase the amorphousphase content and the Li-ion transference number, thereby increasing the room-temperature conductivity of these solid polymer systems. Anodic bonding experiments demonstrate the existence of a well-defined bonding layer at the interface of PEG-LiClO4-SiO2 and aluminum, which is of key importance for strong bonding. Thus, this study examines the use of solid polymer electrolytes for anodic bonding, describing new encapsulation materials for MEMS production.