This
paper presents an investigation of the potential to use aligned
discontinuous carbon fiber dry prepregs as electrodes in structural
supercapacitors (SSCs). The high fiber-matrix interfacial bonding
of the structural composite was achieved by adopting a solid polymer
electrolyte, consisting of poly(vinylidene), lithium triflate, and
epoxy. Processing of the SSC was carried out via dip-coating of the
polymer electrolyte and then cured using a vacuum bag. The electrochemical
performance of the SSCs was measured before and after mechanical loading.
The microstructures of the SSCs as-fabricated and damaged under flexural
loading were identified by μ-CT imaging. An SSC with a specific
capacitance of 0.128 mF/cm2 (11.62 mF/g), a flexural strength
of 47.49 MPa, and a flexural modulus of 8.48 GPa has been achieved,
demonstrating significant improvements in mechanical properties over
those of SSCs based on woven carbon fiber fabric-based electrodes.
The mechanical behavior of the supercapacitors was evaluated by both
quasi-static and cyclic flexural loading tests. The excellent electrochemical
stability of the supercapacitors was validated by a capacitance retention
of above 96% under galvanostatic charge–discharge cycling tests.
The knowledge gained in this work will benefit future research in
the optimization of SSC performance.