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The demand for more efficient energy storage devices has led to the exponential growth of lithium-ion batteries. To overcome the limitations of these systems in terms of safety and to reduce environmental impact, solid-state technology emerges as a suitable approach. This work reports on a three-component solid polymer electrolyte system based on poly(vinylidene fluoride

Battery separators based on silk fibroin (SF) have been prepared aiming at improving the environmental issues of lithium-ioh, batteries. SF materials with three different morphologies were produced: membrane films (SF-F), sponges prepared by lyophilization (SF-L) and: electrospuri membranes (SF-E). The latter Materials presented a suitable porons,three-dimensional microstructure and were soaked with a I M LiPF6 electrolyte: The ionic conductivities for SF-L and SF-E were 1.00 and 0.32 mS cm(-1) at 20 degrees C, respectively. A correlation between the fraction "of beta-sheet conformations and the ionic conductivity was observed. The electrochemical performance of the SF-based materials was evaluated by incorporating them in cathodic half-cells with C-LiFePO4. The discharge capacities of SF-L and SF-E were 126 and 108 mA h g(-1), respectively, at the C/Iirate and 99 and 54 mA h g(-1), respectively, at the 2C-rate. Furthermore, the capacity retention and capacity fade of the SF-L membrane after 50 cycles at the 2C-rate were 72 and 5%, respectively. These electrochemical results show that a high percentage of beta-sheet conformations, were of prime importance to guarantee excellent cycling performance. This work demonstrates that SP-based membranes are appropriate separators for the production of environmentally friendlier lithium-ion batteries., This work was supported by the Portuguese Foundation for Science and Technology (FCT) in the framework of the Strategic Funding UID/FIS/04650/2013, ULD/QUI/00686/2013 and ULD/QUI/00686/2016. The authors thank FEDER funds through the COMPETE 2020 Programme and National Funds through FCT under the projects PTDC/CTM-ENE/5387/2014 and UID/CTM/50025/2013, PEst-OE/QUI/UI0616/2014, and LUMECD (POCI-01-0145-FEDER-016884 and PTDC/CTM-NAN/0956/2014), grants SFRH/BPD/87759/2012 (R.F.P.P.), and SFRH/BPD/112547/2015 (C.M.C.). The authors acknowledge funding by the Spanish Ministry of Economy and Competitiveness (MINECO) through the project MAT2016-76039-C4-3-R (AEI/FEDER, UE) and from the Basque Government Industry Department under the ELKARTEK program., info:eu-repo/semantics/publishedVersion

Luminescent solar concentrators (LSCs) appear as candidates to enhance the performance of photovoltaic (PV) cells and contribute to reduce the size of PV systems, decreasing, therefore, the amount of material needed and thus the cost associated with energy conversion. One way to maximize the device performance is to explore near-infrared (NIR)-emitting centers, resonant with the maximum optical response of the most common Si-based PV cells. Nevertheless, very few examples in the literature demonstrate the feasibility of fabricating LSCs emitting in the NIR region. In this work, NIR-emitting LSCs are reported using silicon 2,3-naphthalocyanine bis(trihexylsilyloxide) (SiNc or NIR775) immobilized in an organic-inorganic tri-ureasil matrix (t-U(5000)). The photophysical properties of the SiNc dye incorporated into the tri-ureasil host closely resembled those of SiNc in tetrahydrofuran solution (an absolute emission quantum yield of ∼0.17 and a fluorescence lifetime of ∼3.6 ns). The LSC coupled to a Si-based PV device revealed an optical conversion efficiency of ∼1.5%, which is among the largest values known in the literature for NIR-emitting LSCs. The LSCs were posteriorly coupled to a Si-based commercial PV cell, and the synergy between the t-U(5000) and SiNc molecules enabled an effective increase in the external quantum efficiency of PV cells, exceeding 20% in the SiNc absorption region.