Multifunctional aramid-based composite quasi-solid-state electrolytes for flexible structure batteries

The integration of flexible structure batteries (FSBs) into electronic equipment is an effective method to significantly improve energy efficiency, whereas traditional battery separators, with poor mechanical properties, low liquid electrolyte capture ability, and weak thermal stability, cannot meet the practical requirements of various applications. To address these challenges, in this study, a multifunctional composite quasi-solid-state electrolyte (CQE) was synthesized by electrospinning poly(vinylidene fluoride-hexafluoropropylene) (PVDF-HFP) fibers on both sides of an aramid nanofibers (ANFs) fibrous film for application in high-performance FSBs. Here, the ANF film serves as a structural framework, thus enhancing the mechanical properties and thermal stability of the CQE, while the “thermal closed-hole effect” and liquid electrolyte capture capability of the PVDF-HFP film in the CQE improve the overall safety of the FSBs. The design strategy of combining 3D-printed electrodes and functional CQE is essential to achieving the integration of structural support and energy storage. Due to the unique characteristics of the CQE, the assembled full-battery (LiFePO₄//Li₄Ti₅O₁₂) demonstrates superior cycling stability (500 cycles). The assembled rectangular bag battery was also shown to be capable of powering an LED lamp under bending conditions and external force, thus providing valuable insights into FSBs design in the field of energy storage.