• Energy Research

Block copolymers (BCPs) as solid electrolytes for batteries are usually designed to have an ion-solvating block for ion conduction and an ionophobic block for providing mechanical strength. Here, we show a novel solid polymer electrolyte (SPE) for sodium batteries based on a poly(vinyl benzoate)-b-poly(diallyldimethyl ammonium bis(trifluoromethanesulfonyl)imide) PVBx-b-PDADMATFSIy-b-PVBx ABA triblock copolymer. The SPE triblock copolymer comprises a polymerized ionic liquid (PIL) ion-solvating block combined with NaFSI salt as an internal block and an ionophilic PVB as an external block. Four distinct compositions with varying chain lengths of the blocks were synthesized by reversible addition−fragmentation chain-transfer (RAFT) polymerization. The neat copolymers were subsequently mixed with NaFSI in a 2:1 mol ratio of Na to ionic monomer units. Through comprehensive analysis using differential scanning calorimetry (DSC), Fourier-transform infrared spectroscopy (FTIR), and nuclear magnetic resonance (NMR), it was revealed that the ion coordination within the polymer–salt mixtures undergoes changes based on the composition of the starting neat polymer. Electrochemical evaluations identified the optimal composition for practical application as PVB11.5K-b-PDADMATFSI33K-b-PVB11.5K, showing an ionic conductivity at 70 °C of 4.2 × 10−5 S cm−1. This polymer electrolyte formulation was investigated for sodium in Na|Na symmetrical cells, showing an overpotential of 200 mV at 70 °C at 0.1 mA cm−2. When applied in a sodium–air battery, the polymer electrolyte membrane achieved a discharge capacity of 1.59 mAh cm−2 at 50 °C.

Abstract Advanced materials for IR applications such as thermal control in spacecraft applications or variable optical attenuators which could replace the present systems have been sought. The use of electrochromic devices based on conducting polymers will add lightness and flexibility to the final device in order to overcome the limitations of the present materials used in IR applications. In this work, we present a new all-plastic electrochromic device with optical contrast (%Δ T ) of 44% at 1971 nm in the IR region based on PEDOT formulations and ionic liquid blends as electrolytes. The switching time of the device is in the order of a few seconds, with a t c 2.7 s and t b 3.8 s.

New redox-active polymer nanoparticles present that the redox potential of the catechol group is affected by the presence of the pyridine. This positive potential gain is associated to the proton trap effect, which benefits the performance of lithium-ion–polymer batteries.

Abstract A series of new sequenced sulfonated naphthalenic polyimides were synthesized containing a flexible aromatic–aliphatic diamine. The obtained membranes present the advantage of being soluble in N -methyl pyrrolidone (NMP) which is a less toxic solvent than the previously used m -cresol. In this work, we report on the solvent and acidification method effects on the properties of the membranes such as density, water uptake, proton conductivity as well as on the performance of these membranes in fuel cell operation. The membranes prepared from NMP solution and acidified with ion-exchange resins give the best results. They have good mechanical properties as well as high ionic conductivity (14.4 × 10 −2 S cm −1 at 80 °C) and good performances as proton exchange membrane (PEM) in fuel cell at 70 °C.

The increasing demands for sustainable energy storage technologies have prompted extensive research in the development of eco-friendly materials for lithium-ion batteries (LIBs). This research article presents the design of biobased latexes, which are fluorine-free and rely on renewable resources, based on isobornyl methacrylate (IBOMA) and 2-octyl acrylate (2OA) to be used as binders in batteries. Three different compositions of latexes were investigated, varying the ratio of IBOMA and 2OA: (1) Poly2OA homopolymer, (2) Poly(2OA0,6-co-IBOMA0,4) random copolymer, and (3) PolyIBOMA homopolymer. The combination of the two monomers provided a balance between rigidity from the hard monomer (IBOMA) and flexibility from the soft one (2OA). The study evaluated the performance of the biobased latexes using sodium carboxymethyl cellulose (CMC) as a thickener and cobinder by fabricating LiNi0.8Mn0.1Co0.1O2 (NMC 811) cathodes. Also, to compare with the state of the art, organic processed PVDF electrodes were prepared. Among aqueous slurries, rheological analysis showed that the CMC + Poly(2OA0,6-co-IBOMA0,4) binder system resulted in the most stable and well-dispersed slurries. Also, the electrodes prepared with this latex demonstrated enhanced adhesion (210 ± 9 N m-1) and reduced cracks compared to other aqueous compositions. Electrochemical characterization revealed that the aqueous processed cathodes using the CMC + Poly(2OA0,6-co-IBOMA0,4) biobased latex displayed higher specific capacities than the control with no latex at high C-rates (100.3 ± 2.1 vs 64.5 ± 0.8 mAh g-1 at 5C) and increased capacity retention after 90 cycles at 0.5C (84% vs 81% for CMC with no latex). Overall, the findings of this study suggest that biobased latexes, specifically the CMC + Poly(2OA0,6-co-IBOMA0,4) composition, are promising as environmentally friendly binders for NMC 811 cathodes, contributing to the broader goal of achieving sustainable energy storage systems.

Hybrid biopolymers, composed of lignin and PEDOT, show enhanced storage capacity for lithium- and sodium-ion batteries.

The use of water‐soluble binders enables the transition to more sustainable batteries by the replacement of toxic N‐methyl‐2‐pyrrolidone (NMP) by water. Herein, two new fluorine‐free poly(ionic liquid)s are proposed as binders for LiNi0.8Mn0.1Co0.1O2 (NMC811) cathodes, based on poly(diallyldimethylammonium) (PDADMA) and two‐phosphate counter anions, which are recognized as effective corrosion inhibitors and electrolyte additives. Due to their high ionic conductivity (10−6 S cm−1 at 25 °C) and ability to prevent degradation of NMC811 particles, the PDADMA phosphate cells are able to achieve a 91% of capacity retention after 90 cycles at 0.5C, similar to the organic fluorinated polyvinylidene fluoride (PVDF) (96%) under the same conditions. However, aqueous sodium carboxymethyl cellulose (Na‐CMC) only provides 81% of capacity retention. Among the PDADMA‐based binders under study, PDADMA‐ diethyl phosphate (PDADMA‐DEP) delivers the highest discharge capacity (101.1 mAh g−1) at high C‐rate (5C). Degradation of Na‐CMC electrodes is observed in postmortem analysis and a notable increase in the charge transfer‐resistance. However, the NMC811 particles preserve their spherical shape when PDADMA‐phosphates are used as binders, also leading to lower polarization resistances and improved lithium diffusion. In conclusion, PDADMA‐phosphates manifest high performance as binders for sustainable NMC811 cathodes, while disposing of fluoropolymers and toxic solvents.