• Energy Research

The most commonly known renewable energy sources include the wind, wave, hydroelectric, biomass, and solar energy. Photovoltaic cells are divided into three main categories and referred to as generations of photovoltaic cells. The first generation of photovoltaic includes the monocrystalline silicon and multicrystalline silicon based solar cells. The second generation solar cells include amorphous silicon-based thin film solar cells - cadmium telluride/cadmium sulfide (CdTe/CdS) solar cells and copper indium gallium selenide (CIGS) solar cells. In third generation solar cells, the electrolyte plays a vital role in deciding the power conversion efficiency as well as stability. Liquid electrolytes are the conventional type of electrolyte and the most widely used transport medium. Polymer electrolytes are ionic conductors prepared by the dissolution of salts in a suitable polymer. Polymer electrolytes are divided into solid polymer electrolyte (SPE), gel polymer electrolyte (GPE) and composite polymer electrolyte (CPE).

The most commonly known renewable energy sources include the wind, wave, hydroelectric, biomass, and solar energy. Photovoltaic cells are divided into three main categories and referred to as generations of photovoltaic cells. The first generation of photovoltaic includes the monocrystalline silicon and multicrystalline silicon based solar cells. The second generation solar cells include amorphous silicon-based thin film solar cells - cadmium telluride/cadmium sulfide (CdTe/CdS) solar cells and copper indium gallium selenide (CIGS) solar cells. In third generation solar cells, the electrolyte plays a vital role in deciding the power conversion efficiency as well as stability. Liquid electrolytes are the conventional type of electrolyte and the most widely used transport medium. Polymer electrolytes are ionic conductors prepared by the dissolution of salts in a suitable polymer. Polymer electrolytes are divided into solid polymer electrolyte (SPE), gel polymer electrolyte (GPE) and composite polymer electrolyte (CPE).

A Guar Gum-based biopolymer (GG), a characteristic non-ionic polysaccharide extracted from guar beans, is utilized in this work as a cost-effective polymer gel electrolyte towards the fabrication of dye-sensitized solar cells (DSSC). A redox electrolyte is prepared by stirring Guar Gum biopolymer with a known amount of LiI/I, 4-tert-butylpyrdine, 1-methyl-3-propylimidazolium iodide, and polyethylene glycol for 24 hrs. The polymer gel electrolyte is carefully characterized through Fourier transform infrared spectra, UV-visible spectrum, Field-emission scanning electron microscopy and Differential Scanning Calorimetry. Using this polymer gel electrolyte, dye-sensitized solar cells are fabricated by sandwiching metal-free organic MK-2 dye coated TiO photoanode and Pt counter electrode as a photocathode. The photoelectrochemical characterization of the fabricated device shows maximum power conversion efficiency of 4.96% instead of 2.13% obtained with the liquid electrolyte without Guar Gum. The electrolyte containing Guar Gum polymer gel shows ionic conductivity (?) of 1.46 S [cm] while the liquid electrolyte show 2.44 S [cm].

A Guar Gum-based biopolymer (GG), a characteristic non-ionic polysaccharide extracted from guar beans, is utilized in this work as a cost-effective polymer gel electrolyte towards the fabrication of dye-sensitized solar cells (DSSC). A redox electrolyte is prepared by stirring Guar Gum biopolymer with a known amount of LiI/I, 4-tert-butylpyrdine, 1-methyl-3-propylimidazolium iodide, and polyethylene glycol for 24 hrs. The polymer gel electrolyte is carefully characterized through Fourier transform infrared spectra, UV-visible spectrum, Field-emission scanning electron microscopy and Differential Scanning Calorimetry. Using this polymer gel electrolyte, dye-sensitized solar cells are fabricated by sandwiching metal-free organic MK-2 dye coated TiO photoanode and Pt counter electrode as a photocathode. The photoelectrochemical characterization of the fabricated device shows maximum power conversion efficiency of 4.96% instead of 2.13% obtained with the liquid electrolyte without Guar Gum. The electrolyte containing Guar Gum polymer gel shows ionic conductivity (?) of 1.46 S [cm] while the liquid electrolyte show 2.44 S [cm].

In the last decades, bio-derived natural materials, such as vegetable oils, polysaccharides and biomass represent a rich source of hydroxyl precursors for the synthesis of polyols which can be potentially used to synthesize "greener" polyurethane foams. Herein a bio-based precursor (obtained from succinic acid) was used as a partial replacement of conventional polyol to synthesize PU foams. A mixture of conventional and bio-based polyol in presence of catalysts, silicone surfactant and diphenylmethane di-isocyanate (MDI) was expanded in a mold and cured for two hours at room temperature. Experimental results highlighted the suitability of this bio-precursor to be used in the production of flexible PU foams. Furthermore the chemo-physical characterization of the resulting foams show an interesting improvement in thermal stability and elastic modulus with respect to the PU foams produced with conventional polyol.

In the last decades, bio-derived natural materials, such as vegetable oils, polysaccharides and biomass represent a rich source of hydroxyl precursors for the synthesis of polyols which can be potentially used to synthesize "greener" polyurethane foams. Herein a bio-based precursor (obtained from succinic acid) was used as a partial replacement of conventional polyol to synthesize PU foams. A mixture of conventional and bio-based polyol in presence of catalysts, silicone surfactant and diphenylmethane di-isocyanate (MDI) was expanded in a mold and cured for two hours at room temperature. Experimental results highlighted the suitability of this bio-precursor to be used in the production of flexible PU foams. Furthermore the chemo-physical characterization of the resulting foams show an interesting improvement in thermal stability and elastic modulus with respect to the PU foams produced with conventional polyol.

Abstract: Electronic companies must continuously innovate to meet the growing demand for safety, reliability, environmental sustainability, and cost-effective designs. Recently, there has been increasing interest from researchers, industry, and government in developing eco-friendly electronic materials that dissolve completely after use, leaving behind harmless byproducts. This work presents an example of an energy storage device based on completely biodegradable and low-cost materials, created by assembling bio-based polymers with carbonaceous fillers. Polymeric materials derived from renewable resources, such as proteins, starch, and cellulose, were processed into plastic-like products with desirable structural and functional properties. Their hydrophilic nature, rapid degradation, and chemical complexity allow these materials to serve multiple functions, from structural support to barrier protection. Notably, the ability of biopolymers to bind low-molecular-weight species (e.g., water and glycerol) and inorganic conductive particles (e.g., graphite flakes, carbon nanotubes, or graphene) results in transient dielectric composites with a surface capacitance higher than that of traditional devices based on activated carbon. These materials have the potential to revolutionize applications ranging from "green" consumer electronics to bio-resorbable medical implants-opportunities that were previously limited by the absence of suitable materials. Funding: This work was supported by the project No. CZ.02.01.01/00/22_008/0004631 “Materials and technologies for sustainable development within the Jan Amos Komensky Operational Program financed by the European Union.