Solid-state sodium-ion batteries (ss-SIBs) are a promising alternative to commercially available lithium-ion batteries for next-generation energy storage applications due to the abundance and cost-effectiveness of sodium over lithium. Herein, using a facile solution casting process, a high sodium-ion conductive, filler-less composite solid polymer electrolyte (SPE) film based on poly(vinylidene fluoride) polymer, poly(vinyl pyrrolidone) (PVP) binder, and NaPF 6 salt for ss-SIB has been successfully fabricated. Total conductivities of 8.51 × 10 −4 and 8.36 × 10 −3 S cm −1 at 23 and 83 °C, respectively, were observed from the SPE. A hybrid symmetric half-cell assembly using Na electrode and 1 M NaClO 4 in ethylene carbonate (EC) and propylene carbonate (PC) (EC/PC = 1:1 wt %) electrolyte showed excellent Na plating−stripping performance at 10 mA cm −2 at 23 °C. The study showed that PVP binder played an important role in achieving good Na ion conductivity and excellent Na plating−stripping performance, highlighting the applicability of the as-prepared SPE in next-generation high-power rechargeable SIBs. A full cell with an SPE, a Na anode, and a Na 3 V 2 (PO 4 ) 3 cathode showed a discharge capacity of 93.2 mAh g −1 at 0.1 C with 86% capacity retention and 99.68% Coulombic efficiency for 100 cycles.

Sodium gadolinium silicate solid electrolyte showed an outstanding sodium plating/stripping performance for 1000 cycles that proves excellent interfacial contact between the sodium anode and solid electrolyte.

Dye-sensitized solar cells (DSSCs) enticed the attention in photovoltaic design due to their unique features of ease of fabrication, low-cost materials, tunable color, and flexibility. In this work, we studied the performance of a low cost dye-sensitized solar cell structure with several natural dyes as a sensitizer. Titanium dioxide (TiO 2) was used as the semiconducting layer. The TiO 2 film was fabricated on Florine doped Tin Oxide (FTO) glass plate and was annealed and sintered for an hour at 450°C temperature to create a mesoporous layer. To reduce the manufacturing cost, we used Carbon black instead of Platinum (Pt) as a counter electrode. Carbon black provides excellent stability and shows high catalytic ability along with its low cost as the counter electrode in the DSSCs. Eight different dyes have been extracted and purified by Silica gel column chromatography to use in the DSSCs. UV-Visible absorption spectroscopy and fluorescence spectroscopy has been done to measure the absorbance coefficient and fluorescence coefficient of each of the cells. The cells with an additional peak in the fluorescence spectra showed much better electrical performance compared with others. Among the fabricated DSSCs, the Curcuma longa based DSSC gives the highest open-circuit voltage of 0.5959 V and short circuit current density of 1.06 mA/cm 2. The study also indicates that the dyes with a peak at 380 nm to 400 nm wavelength at fluorescence spectrum has better photovoltaic performance rather with a moderate absorbance spectrum.

Solid-state sodium-ion batteries (ss-SIBs) are a promising alternative to commercially available lithium-ion batteries (LIBs) for next-generation energy storage applications. They have lower production costs and are safer than LIBs. Moreover, sodium is more abundant than lithium. The incorporation of solid polymer electrolytes (SPEs) into SIBs has been attracting much more attention due to the easy processability, low costs, safe usability, modification scope, and abundance of polymers. However, SPEs for ss-SIBs with high ionic conductivity and low interfacial resistance between electrolytes and electrodes are lacking. In addition, SPEs face major challenges such as suitable manufacturing methods and the lack of knowledge about low-cost ss-SIBs assembly. Herein, using a facile solution casting process, we have successfully fabricated a high sodium-ion conductive composite SPE film based on polyvinylidene fluoride (PVDF) polymer, polyvinylpyrrolidone (PVP) binder, and NaPF6 salt. A comprehensive characterization has been conducted using X-Ray Diffraction (XRD), Scanning Electron Microscopy (SEM), Fourier Transform Infrared (FTIR), Thermogravimetric Analysis (TGA), Raman, and electrochemical impedance spectroscopy techniques to investigate the structural, thermal, and electrochemical performance of the as-prepared SPE films. High ionic conductivity (8.51 x 10-4 S cm-1 and 8.36 x 10-3 S cm-1 at 23°C and 78 °C, respectively) was observed from the SPE. A hybrid symmetric half-cell assembly (Na foil + 20 µL of 1 M NaClO4 in ethylene carbonate (EC) and propylene carbonate (PC) (EC: PC = 1:1) + Carbon-cloth |SPE| Carbon-cloth + 20 µL of 1 M NaClO4 in EC and PC (EC: PC = 1:1) | Na foil) showed excellent Na plating-stripping performance up to 8 mA cm-2 for 100 cycles. In addition, Na+ transfer mechanism in the composite electrolyte has been investigated using impedance and dielectric spectroscopy. The results indicate the promising applicability of SPEs in next-generation high-power rechargeable SIBs.