The PVA-based hydrogel electrolyte, characterized by its high ionic conductivity and degradability, holds significant promise for applications in flexible supercapacitors. However, pure PVA hydrogel electrolytes have suffered from deficiencies in flexibility, self-healing properties, and anti-freezing performance. In this study, a novel approach was employed by in situ blending polyvinyl alcohol (PVA) with zinc chloride (ZnCl₂) dissolved cellulose. When the mass ratio of PVA to cellulose was 2 : 1, the resulting PVA/cellulose composite hydrogel electrolyte exhibited a commendable tensile strength (198 kPa) and remarkably high elongation at break (2415%); the assembled zinc/carbon asymmetric supercapacitor demonstrated an area-specific capacitance of 636 mF cm⁻² (2 mA cm⁻²). Moreover, at −30 °C, the capacitance retention exceeded 94%, indicating excellent anti-freezing properties. Subsequent electrical performance tests on the self-healed hydrogel electrolyte capacitors yielded a capacitance retention rate exceeding 94%, demonstrating outstanding self-healing properties. This novel class of hydrogel electrolytes provides a viable research perspective for addressing the aforementioned issues. Additionally, this study also involved straightforward treatment of used hydrogels, allowing for the recovery of high-value zinc salts such as zinc carbonate and zinc chloride, with a recycling efficiency as high as 55%. The entirety of the experiment exhibited an environmentally friendly and sustainable engineering process.

Understanding how to develop highly efficient and robust adsorbents for the removal of organic dyes in wastewater is crucial in the face of the rapid development of industrialization. Herein, d-Ti₃C₂T_x nanosheets (MXene) were combined with sodium alginate (SA), followed by electrospinning and successive Ca²⁺-mediated crosslinking, giving rise to a series of SA/MXene nanofiber membranes (NMs). The effects of the MXene content of the NMs on the adsorption performance for methylene blue (MB) were investigated systemically. Under the optimum MXene content of 0.74 wt.%, SA/MXene NMs possessed an MB adsorption capacity of 440 mg/g, which is much higher than SA/MXene beads with the same MXene content, pristine MXene, or electrospinning SA NMs. Furthermore, the optimum SA/MXene NMs showed excellent reusability. After the adsorbent was reused ten times, both the MB adsorption capacity and removal rate could remain at 95% of the levels found in the fresh samples, which indicates that the electrospinning technique has great potential for developing biomass-based adsorbents with high efficiency.

Photochromic hydrogels have great potential for inkless printing, smart display devices, anti-counterfeiting and encryption.