High sodium conductive polymer electrolyte-based nanoclusters in supercapacitor

The sodium-ion polymer electrolytes (PEs) spur the development of the high safe solid batteries due to their merits of safety, flexibility, lower interfacial resistance with electrodes, and easy processing. Herein, a rational strategy is developed to construct the PE, which can integrate the excellent sodium ion conductivity with the mechanical performances. This strategy applies the nano-sized metal oxide clusters (MOCs) not only to supply the sodium ions but also to inhibit the polymer crystallization. The released polymer chains, crosslinked via physical crosslinking points (nanoclusters), form a network that provides the electrolyte film with toughness over a wide temperature range. The targeted electrolyte exhibits excellent Na-ion conductivity of 3.8 × 10⁻⁴ S cm⁻¹ at room temperature, tensile strength up to 0.74 Mpa and breaking elongation of 23 %. In addition, this PE widens the electrochemical stability window of the aqueous Na-ion supercapacitor up to 2.0 V since the water molecules are effectively confined via the strong interactions among components. Our research on sodium polymer electrolytes combined by nanoclusters and PVA holds significant promise for advancing solid-state sodium supercapacitors— a new generation of high-performance, safe, and cost-effective energy storage solutions.