Development and Multifunctional Characterization of a Structural Sodium-Ion Battery Using a High-Tensile-Strength Poly(ethylene oxide)-Based Matrix Composite

Structural batteries are gaining attention and can play a significant role in designing emission-free lightweight defense and transport systems such as aircraft, unmanned air vehicles, electric cars, public transport, and vertical takeoff and landing (VTOL)-urban air traffic. Such an approach of integrated functions contributes to overall mass reduction, high performance, and enhanced vehicle spaciousness. The present work focuses on developing and characterizing multifunctional structural sodium-ion battery components by using a high-tensile-strength structural electrolyte (SE) prepared by incorporating a glass fiber sandwiched between thin solid-state poly(ethylene oxide)-based composite electrolyte layers. The electrochemical and mechanical characterization of the structural electrolyte shows multifunctional performance with a tensile strength of 40.9 MPa and an ionic conductivity of 1.02 × 10–4 S cm–1 at 60 °C. It displays an electrochemical window of 0 to 4.5 V. The structural electrode is fabricated using a heat press by pressing intermediate-modulus carbon fibers (CFs) against the structural electrolyte, and it shows a high tensile strength of 91.3 MPa. The fabricated structural battery CF||SE||Na provides a typical energy density of 23 Wh kg–1 and performs 500 cycles while retaining 80% capacity until 225 cycles. The investigation of sodium structural battery architecture in this preliminary work demonstrates intercalation of sodium ions in intermediate modulus-type carbon fiber electrodes, shows multifunctional performance with excellent cycling stability and structural strength, and provides an alternative path to current structural battery designs.