Search

Structural electrolytes present advantages over liquid varieties, which are critical to myriad applications. In particular, structural electrolytes based on polymerized ionic liquids or poly(ionic liquids) (pILs) provide wide electrochemical windows, high thermal stability, nonvolatility, and modular chemistry. However, current methods of fabricating structural electrolytes from pILs and their composites present limitations. Recent advances have been made in 3D printing pIL electrolytes, but current printing techniques limit the complexity of forms that can be achieved, as well as the ability to control mechanical properties or conductivity. We introduce a method for fabricating architected pIL composites as structural electrolytes via embedded 3D (EMB3D) printing. We present a modular design for formulating ionic liquid (IL) monomer composite inks that can be printed into sparse, lightweight, free-standing lattices with different functionalities. In addition to characterizing the rheological and mechanical behaviors of IL monomer inks and pIL lattices, we demonstrate the self-sensing capabilities of our printed structural electrolytes during cyclic compression. Finally, we use our inks and printing method to spatially program self-sensing capabilities in pIL lattices through heterogeneous architectures as well as ink compositions that provide mixed ionic-electronic conductivity. Our free-form approach to fabricating structural electrolytes in complex, 3D forms with programmable, anisotropic properties has broad potential use in next-generation sensors, soft robotics, bioelectronics, energy storage devices, and more.

Ionic liquid (IL) additives proved to have a positive effect on the device efficiency and stability of perovskite solar cells. However, since ILs are small molecules and undergo Coulomb interactions, they can easily aggregate and evaporate over long times, which would cause instabilities during a long-term device operation. To overcome these problems, we polymerize ILs into macromolecules and incorporate them into perovskite films as well as into the corresponding solar cells. Both cations and anions of the used poly[1-(2-acryloylethyl)-3-methylimidazolium] bis (trifluoromethane) sulfonamides (PAEMI-TFSIs) are designed to coordinate with the Pb and I of PbI 6 2- octahedra, respectively, which changes the crystallization behavior of the perovskite films. Importantly, the PAEMI-TFSI efficiently passivates electronic defects on the grain boundaries and thereby enhances the charge-carrier transport in the perovskite film. As a result, PAEMI-TFSI-modified MAPbI 3 solar cells show a high power conversion efficiency of 22.4% and an excellent storage stability (92% of the initial efficiency remains after 1200 h operation in a nitrogen atmosphere for nonencapsulated devices).

Ice build-up on solid surfaces causes significant economic losses for a range of industries. One solution to this problem is the development of coatings with low ice adhesion strength. Amphiphilic poly(ionic liquid) (PIL)-based surfaces have been recently reported for antifogging/antifrosting applications. However, they have possible anti-icing properties through lowering the ice adhesion strength that have yet to be reported. Herein, we designed well-defined triblock copolymers composed of a polydimethylsiloxane component coupled with PIL segments of poly([2 (methacryloyloxy)ethyl] trimethylammonium chloride) (PMETAC), which were subsequently UV-cured with an oligo(ethylene glycol) dimethacrylate (OEGDMA) cross-linker. The structure-property relationships of the resultant semi-interpenetrating polymer networks (SIPNs) were investigated by varying the counterion (i.e., trimethylammonium bis(trifluoromethanesulfonyl)imide (TFSI - )) and the content of the PIL segments and cross-linker. An ice adhesion strength as low as 13.3 ± 8.6 kPa was observed for the coating containing 12.5 wt % of PMETAC segment and 5 wt % of OEGDMA, which is one of the lowest values reported so far for the amphiphilic coatings. Characterization of the coatings in terms of surface features, wettability, and hydration states have enabled the elucidation of different deicing mechanisms. Self-lubrication due to the existence of nonfreezable bound water led to the obtained low ice adhesion strength. This work offers a new approach for the exploration of PIL-based icephobic coatings for practical applications.

High-performance solid-state electrolytes with healability to repair mechanical damages are important for the fabrication of Li-ion batteries (LIBs) with enhanced safety and prolonged service life. In this study, we present the fabrication of healable, highly conductive, flexible, and nonflammable ionogel electrolytes for use in LIBs by loading ionic liquids and Li salts within a hydrogen-bonded supramolecular poly(ionic liquid) copolymer network. The ionogel electrolytes exhibit ionic conductivities as high as 10 -3 S/cm, which is comparable to the conventional liquid electrolytes. The Li/LiFePO 4 battery assembled with the ionogel membrane exhibits excellent cycling performance and delivers a steady high discharge capacity of 147.5 mA h g -1 and Coulombic efficiency of 99.7% after 120 cycles at the charge/discharge rate of 0.2 C. Importantly, the ionogel membranes can heal damages outside or inside a battery because of the reversible nature of the supramolecular interactions between the components. The damaged ionogel membranes after being healed can effectively restore the original performance of the LIBs.

Interfacial layers play a critical role in building up the Ohmic contact between electrodes and functional layers in organic photovoltaic (OPV) solar cells. These layers are based on either inorganic oxides (ZnO and TiO 2 ) or water-soluble organic polymers such as poly[(9,9-dioctyl-2,7-fluorene)-alt-(9,9-bis(3'-(N,N-dimethylamino)propyl)-2,7-fluorene)] and polyethylenimine ethoxylated (PEIE). In this work, we have developed a series of novel poly(ionic liquid) nonconjugated block copolymers for improving the performance of inverted OPV cells by using them as work function modifiers of the indium tin oxide (ITO) cathode. Four nonconjugated polyelectrolytes (n-CPEs) based on polystyrene and imidazolium poly(ionic liquid) (PSImCl) were synthesized by reversible addition-fragmentation chain transfer polymerization. The ratio of hydrophobic/hydrophilic block copolymers was varied depending on the ratio of polystyrene to the PSImCl block. The ionic density, which controls the work function of the electrode by forming an interfacial dipole between the electrode and the block copolymers, was easily tuned by simply changing the PSImCl molar ratio. The inverted OPV device with the ITO/PS 29 -b-PSImCl 60 cathode achieved the best power conversion efficiency (PCE) of 7.55% among the synthesized block copolymers, exhibiting an even higher PCE than that of the reference OPV device with PEIE (7.30%). Furthermore, the surface properties of the block copolymers films were investigated by contact angle measurements to explore the influence of the controlled hydrophobic/hydrophilic characters on the device performances.