Rapid photoprinting of piezoelectric solid polymer electrolytes for scalable structural energy storage composites

3D printing of solid polymer electrolytes (SPEs) offers a scalable platform for fabricating intricate architectures whilst maintaining the desired electrochemical and mechanical properties. Here, we present an innovative approach for the fabrication of bicontinuous SPEs, containing an ion-conductive solvate ionic liquid (SIL) network within a mechanically reinforcing polymer, via photopolymerisation using masked stereolithography (MSLA). Compared to mould-cured (bulk) SPEs of identical composition, the additively manufactured samples exhibited superior homogeneity and enhanced electrochemical and mechanical performance, attributed to the uniform phase distribution and controlled microstructure enabled by additive manufacturing. Additionally, these samples also displayed piezoelectric properties, with a linear correlation between generated current/potential and applied pressure, highlighting their applicability in energy harvesting and sensing applications. Building on this, we further demonstrate the potential of this rapid prototyping process for structural energy storage by directly printing the SPE onto carbon fibre, functionalised with a redox-active 2,6-diaminoanthraquinone, and viability of a separator-less structural supercapacitor with a snap-fit interlocking polymer electrolyte design as a proof of concept for rapid prototyping of load-bearing energy storage devices.