Gel Electrolytes with Polyamidopyridine Dendron Modified Talc for Dye-Sensitized Solar Cells

Gel Polymer Electrolytes with Talc as a Natural Mineral Filler and a Biodegradable Polymer Matrix in Sodium-Ion Batteries

A gel polymer electrolyte based on poly(vinyl alcohol) (PVA) is used in sodium-ion batteries (SIBs). The use of biodegradable and water-soluble polymer potentially reduces the negative environmental impact. The other components include sodium salt (NaPF6 ), sulfolane (TMS) as a plasticizer and talc. For the first time, natural and abundant talc has been used as an inert filler in a gel polymer electrolyte. The best results were obtained for moderate amounts of filler (1 and 3 wt%). Then, an increase in the conductivity, transference numbers, and thermal stability of the membranes was observed. Moreover, the presence of talc had a positive effect on the cyclability of the hard carbon electrode. The discharge capacity after 50 cycles of HC|1 % T_TMS|Na and HC|3 % T_TMS|Na was 243 and 225 mAh g-1 , respectively. The use of talc in gel polymer electrolytes containing sodium ions improves the safety and efficiency of SIBs.

Highly efficient and stable ionic liquid-based gel electrolytes

Gel electrolytes are promising candidates for dye-sensitized solar cells (DSSCs) and other devices, but the ways to obtain stable gels always result in sacrifice of their ionic conductivity. This contradiction seriously limits the practical application of gel electrolytes. Herein, a new design strategy using rich carboxylic group-modified silica nanoparticles (COOH-SiO₂) with a branched, well-organized framework to develop ionic liquid-based gel electrolytes possessing high conductivity is demonstrated. The branched network of COOH-SiO₂ and the strong interaction in electrolytes result in the effective solidification of ionic liquids. Moreover, adding COOH-SiO₂ to ionic liquid electrolytes contributes to salt dissociation, decreases the activation energy, and improves the charge transport and recombination characteristics at the electrolyte/electrode interface. DSSCs fabricated with COOH-SiO₂ nanoparticles deliver a higher short-circuit photocurrent density (J_sc) than the reference cell. A maximum efficiency of 8.02% with the highest J_sc value of 16.60 mA cm^-2 is obtained for solar cells containing 6 wt% COOH-SiO₂.

Enhancing the Efficiency of a Dye-Sensitized Solar Cell Based on a Metal Oxide Nanocomposite Gel Polymer Electrolyte

To overcome the critical limitations of liquid-electrolyte-based dye-sensitized solar cells, quasi-solid-state electrolytes have been explored as a means of addressing long-term device stability, albeit with comparatively low ionic conductivities and device performances. Although metal oxide additives have been shown to augment ionic conductivity, their propensity to aggregate into large crystalline particles upon high-heat annealing hinders their full potential in quasi-solid-state electrolytes. In this work, sonochemical processing has been successfully applied to generate fine Co₃O₄ nanoparticles that are highly dispersible in a PAN:P(VP-co-VAc) polymer-blended gel electrolyte, even after calcination. An optimized nanocomposite gel polymer electrolyte containing 3 wt % sonicated Co₃O₄ nanoparticles (PVVA-3) delivers the highest ionic conductivity (4.62 × 10^-3 S cm^-1) of the series. This property is accompanied by a 51% enhancement in the apparent diffusion coefficient of triiodide versus both unmodified and unsonicated electrolyte samples. The dye-sensitized solar cell based on PVVA-3 displays a power conversion efficiency of 6.46% under AM1.5 G, 100 mW cm^-2. By identifying the optimal loading of sonochemically processed nanoparticles, we are able to generate a homogenous extended particle network that effectively mobilizes redox-active species through a highly amorphous host matrix. This effect is manifested in a selective 51% enhancement in photocurrent density (J_SC = 16.2 mA cm^-2) and a lowered barrier to N719 dye regeneration (R_CT = 193 Ω) versus an unmodified solar cell. To the best of our knowledge, this work represents the highest known efficiency to date for dye-sensitized solar cells based on a sonicated Co₃O₄-modified gel polymer electrolyte. Sonochemical processing, when applied in this manner, has the potential to make meaningful contributions toward the ongoing mission to achieve the widespread exploitation of stable and low-cost dye-sensitized solar cells.