Fabrication and characterization of high-tensile-strength PEO–PVP blend-based multifunctional composites for sodium-ion structural batteries

Abstract

The structural integration of energy storage could play a pivotal role in designing more efficient, lightweight systems such as electric transport, internet of things (IoT) devices and autonomous systems. The current work focuses on the fabrication and characterization of novel multifunctional composites for sodium-ion structural batteries. A PEO–PVP polymer matrix with added InAs nanowires and glass fiber reinforcements was used to fabricate a structural electrolyte (GF_PEO–PVP–InAsNW–NaPF₆). It shows an ionic conductivity of 1.7 × 10⁻⁴ S cm⁻¹ at 70 °C, an electrochemical stability window of 0 to 3.7 V, a sodium ion transference number of 0.40 and a high tensile strength of 76.5 MPa. A structural electrode is fabricated by laminating the electrolyte with intermediate modulus carbon fibers (CF) and it shows a high tensile strength of 171.5 MPa. The structural CF‖GF_PEO–PVP–InAsNW–NaPF₆‖Na cell provides a typical energy density of 17.5 Wh kg⁻¹ at 0.1C rate and accomplished 600 cycles at 0.8C rate while retaining 80% capacity at the end of 280 cycles. The investigation in this preliminary work reveals addition of InAs nanowire fillers enhances both the tensile strength and ionic conductivity of the structural electrolyte and boosts the cycling stability of the structural cell by delaying sodium dendrite formation, and the usage of intermediate modulus carbon fibers in the fabricated electrodes demonstrates sodium-ion intercalation capabilities. The fabricated components display multifunctional performance and show good potential for sodium-ion structural battery applications.