Porous structural battery composite for coordinated integration of mechanical and electrical functionalities

Structural battery composites (SBCs) represent an emerging multifunctional technology in which materials functionalized with energy storage capabilities are used to build load-bearing structural components. However, due to the liquid electrolyte contamination in structural battery electrolyte (SBE) and the large volume expansion of active battery materials, the poor interlayer interfacial in multilayer SBCs often causes difficulties in practical use. In this study, a new porous LiFePO₄-graphite SBC is designed and fabricated by independently distributing battery materials and resin matrix on carbon fiber fabric in pattern lattice form to prepare electrodes prepreg. The cured porous composite framework supports the load-bearing function while limiting the electrochemical reaction in liquid electrolyte within lattices. The electrodes show reversible electric resistance after 3000 bending cycles with radius as small as 10 mm. The mechanical properties enhance significantly with tensile strength of 486.1 MPa and Young's modulus of 9.1 GPa compared to that with a liquid–solid biphasic mixed SBE structure. The SBC also exhibits a favorable capacity of 27.8 mAh/g at 0.1C. This straightforward integration path of mechanical and electrical functionalities is compatible with the manufacturing process of aerospace composite structures, which will provide an efficient and convenient energy supply solution for distributed electronics.