Mechanical characterisation of a structural battery electrolyte

Structural battery composites require a structural electrolyte to work. The structural battery electrolyte has a bicontinuous microstructure which enables its dual roles: mechanical load transfer and ion transport between the electrodes. These structural electrolytes are difficult to characterise mechanically via bulk tests. For this reason, no extensive characterisation of the mechanical properties of the structural battery electrolyte has been performed to date. In this study, we highlight the many challenges of these types of tests, including the complexity of sample manufacturing, preparation and testing. We further demonstrate a method to prepare test samples and to perform mechanical tests on the structural battery electrolyte. The executed test campaign provides measures of Young's modulus (approximately 412 MPa) and Poisson's ratio (0.34), as well as tensile (4.85 MPa) and compressive strength (32.66 MPa) and strain to failure (2.49 % and 28.11 % in tension and compression, respectively). In addition, cure shrinkage is investigated and found insignificant. These results are crucial for the further development of structural battery composites as they allow for accurate prediction of their internal stress states. • A procedure to manufacture tensile and compressive structural battery electrolyte test samples has been established. • The structural battery electrolyte mechanical performance under tension and compression loads is characterised. • The obtained data will enable reliable prediction of stresses in the structural electrolyte during its use.