Polyethylene oxide (PEO)-based composite polymer electrolytes (CPEs) containing in situ SiO₂ fillers are prepared using an electrostatic spinning method at room temperature. Through the in situ hydrolysis of tetraethyl silicate (TEOS), the generated SiO₂ nanospheres are uniformly dispersed in the PEO matrix to form a 3D ceramic network, which enhances the mechanical properties of the electrolyte as a reinforcing phase. The interaction between SiO₂ nanospheres and PEO chains results in chemical bonding with a decrease in the crystallinity of the PEO matrix, as well as the complexation strength of PEO chains with lithium ions during the hydrolysis process. Meanwhile, the addition of SiO₂ nanospheres can disturb the orderliness of PEO chain segments and further suppress the crystallization of the PEO matrix. Therefore, improved mechanical/electrochemical properties can be obtained in the as-spun electrolyte with the unique one-dimensional high-speed ion channels. The electrospun CPE with in situ SiO₂ (10 wt%, ca. 45 nm) has a higher ionic conductivity of 1.03 × 10⁻³ S cm⁻¹ than that of the mechanical blending one. Meanwhile, the upper limit of the electrochemical stability window is up to 5.5 V versus Li⁺/Li, and a lithium-ion migration number can be of up to 0.282 at room temperature. In addition, in situ SiO₂ electrospun CPE achieves a tensile strength of 1.12 MPa, elongation at the break of 488.1%, and it has an excellent plasticity. All in all, it is expected that the electrospun CPE prepared in this study is a promising one for application in an all-solid-state lithium-ion battery (LIB) with a high energy density, long life cycle, and high safety.

PEO–LiClO₄–fumed SiO₂ composite solid-state electrolyte is successfully fabricated with superior 3 migration capacity to Li⁺ and improved electrochemical performance for lithium-metal battery by a 4 facile preparation process.

With the development of the flexible electronics technology, polyvinylidene fluoride (PVDF) and its composite films have emerged as critical materials for flexible sensors, owing to their exceptional piezoelectric properties, mechanical flexibility, and chemical stability. This paper reviews the latest advancements in PVDF-based composite films with a focus on optimizing their piezoelectric characteristics. It examines the incorporation of inorganic nanoparticles, including BaTiO₃, ZnO, and Mxene, as well as organic fillers, to enhance the piezoelectric coefficient and electromechanical coupling coefficient. These improvements facilitate high sensitivity and stability in applications such as pressure, vibration, and biomedical sensors. The paper also examines the influence of various fabrication techniques, including printing and magnetron sputtering, as well as electrode deposition methods, on performance metrics. Although PVDF-based composite films exhibit the outstanding performance, their scalability is constrained by cost and manufacturing complexity. Future research should prioritize cost reduction and enhance integration to satisfy the requirements of smart sensors and wearable devices, thereby promoting broader application in multimodal sensing and efficient energy conversion. Graphical Abstract

The porous organic cage oligomers as giant molecules were fabricated through post-synthesized modification in a controlled way and moderate yields.