Engineered Interfaces in Hybrid Ceramic–Polymer Electrolytes for Use in All-Solid-State Li Batteries

Composites of inorganic lithium ion conducting glass ceramics (LICGCs) and organic polymers may provide the best combination of properties for safe solid separators in lithium or lithium ion batteries to replace the currently used volatile liquid electrolytes. A key problem for their use is the high interfacial resistance that develops between the two, increasing the total cell impedance. Here we show that the application of a thin conformal SiO₂ coating onto a LICGC followed by silanization with (CH₃CH₂O)₃–Si–(OCH₂CH₂)–OCH₃ in the presence of LiTFSI results in good adhesion between the SiO₂ and the LICGC, a low resistance interface, and good wetting of Li⁰. Further, the cross-linked polymer formed on the surface of the silanated SiO₂ interface formed from excess (CH₃CH₂O)₃–Si–(OCH₂CH₂)–OCH₃ prevents corrosion of the LICGC by Li⁰ metal. The use of SiO₂ as a “glue” enables compatibilization of inorganic ceramics with other polymers and introduction of interfacial pendant anions

Nanoparticle-Supported Lipid Bilayers as an In Situ Remediation Strategy for Hydrophobic Organic Contaminants in Soils

Polycyclic aromatic hydrocarbons (PAHs) are persistent environmental organic contaminants due to their low water solubility and strong sorption onto organic/mineral surfaces. Here, nanoparticle-supported lipid bilayers (NP-SLBs) made of 100-nm SiO₂ nanoparticles and the zwitterionic lipid 1,2-dimyristoyl-<i>sn</i>-glycero-3-phosphocholine (DMPC) are investigated as constructs for removing PAHs from contaminated sites, using benzo­[a]­pyrene (BaP) as an example. DMPC in the form of small unilamellar vesicles (SUVs) or DMPC-NP-SLBs with excess DMPC-SUVs to support colloidal stability, when added to saturated BaP solutions, sorb BaP in ratios of up to 10/1 to 5/1 lipid/BaP, over a 2-week period at 33 °C. This rate increases with temperature. The presence of humic acid (HA), as an analog of soil organic matter, does not affect the BaP uptake rate by DMPC-NP-SLBs and DMPC-SUVs, indicating preferential BaP sorption into the hydrophobic lipids. HA increases the zeta potential of these nanosystems, but does not disrupt their morphology, and enhances their colloidal stability. Studies with the common soil bacteria <i>Pseudomonas aeruginosa</i> demonstrate viability and growth using DMPC-NP-SLBs and DMPC-SUVs, with and without BaP, as their sole carbon source. Thus, NP-SLBs may be an effective method for remediation of PAHs, where the lipids provide both the method of extraction and stability for transport to the contaminant site

Tuning the Self-Assembling of Pyridinium Cationic Lipids for Efficient Gene Delivery into Neuronal Cells

We are reporting a new set of biocompatible, low-toxicity pyridinium cationic lipids based on a dopamine backbone on which hydrophobic alkyl tails are attached via an ether linkage. Due to their optimized hydrophilic/hydrophobic interface and packing parameter, the new lipids are able to strongly self-assemble either alone or when coformulated with colipids DOPE or cholesterol. The supra-molecular assemblies generated with the novel pyridinium amphiphiles were characterized in bulk and in solution via a combination of techniques including DSC, nanoDSC, SAXS, TOPM, TEM, DLS, zeta potential, and electrophoretic mobility measurements. These cationic bilayers can efficiently condense and deliver DNA to a large variety of cell lines, as proven by our self-assembling/physicochemical/biological correlation study. Using the luciferase reporter gene plasmid, we have also conducted a comprehensive structure–activity relationship study, which identified the best structural parameters and formulations for efficient and nontoxic gene delivery. Several formulations greatly surpassed established transfection systems with proved in vitro and in vivo efficiency, being able to transfect a large variety of malignant cells even in the presence of elevated levels of serum. The most efficient formulation was able to transfect selectively primary rat dopaminergic neurons harvested from nucleus accumbens, and neurons from the frontal cortex, a premise that recommends these synthetic vectors for future in vivo delivery studies for neuronal reprogramming

Lipid Exchange and Transfer on Nanoparticle Supported Lipid Bilayers: Effect of Defects, Ionic Strength, and Size

Lipid exchange/transfer has been compared for zwitterionic 1,2-dimyristoyl-<i>sn</i>-glycero-3-phosphocholine (DMPC) and 1,2-dimyristoyl-d₅₄-<i>sn</i>-glycero-3-phosphocholine (DMPC) small unilamellar vesicles (SUVs) and for the same lipids on silica (SiO₂) nanoparticle supported lipid bilayers (NP-SLBs) as a function of ionic strength, temperature, temperature cycling, and NP size, above the main gel-to-liquid crystal phase transition temperature, <i>T</i>_m, using d- and h-DMPC and DPPC. Increasing ionic strength decreases the exchange kinetics for the SUVs, but more so for the NP-SLBs, due to better packing of the lipids and increased attraction between the lipid and support. When the NP-SLBs (or SUVs) are cycled above and below <i>T</i>_m, the exchange rate increases compared with exchange at the same temperature without cycling, for similar total times, suggesting that defects provide sites for more facile removal and thus exchange of lipids. Defects can occur: (i) at the phase boundaries between coexisting gel and fluid phases at <i>T</i>_m; (ii) in bare regions of exposed SiO₂ that form during NP-SLB formation due to mismatched surface areas of lipid and NPs; and (iii) during cycling as the result of changes in area of the lipids at <i>T</i>_m and mismatched thermal expansion coefficient between the lipids and SiO₂ support. Exchange rates are faster for NP-SLBs prepared with the nominal amount of lipid required to form a NP-SLB compared with NP-SLBs that have been prepared with excess lipids to minimize SiO₂ patches. Nanosystems prepared with equimolar mixtures of NP-SLBs composed of d-DMPC (d^DMPC-NP-SLB) and SUVs composed of h-DMPC (h^DMPC-SUV) show that the calorimetric transition of the “donor” h^DMPC-SUV decreases in intensity without an initial shift in <i>T</i>_m, indicating that the “acceptor” d^DMPC-NP-SLB can accommodate more lipids, through either further fusion or insertion of lipids into the distal monolayer. Exchange for d/h^DMPC-NP-SLB is in the order 100 nm SiO₂ > 45 nm SiO₂ > 5 nm SiO₂

Highly Durable, Self-Standing Solid-State Supercapacitor Based on an Ionic Liquid-Rich Ionogel and Porous Carbon Nanofiber Electrodes

A high-performance, self-standing solid-state supercapacitor is prepared by incorporating an ionic liquid (IL)-rich ionogel made with 95 wt % IL (1-ethyl-3-methylimidazolium bis­(trifluoromethylsulfonyl)­imide) and 5 wt % methyl cellulose, a polymer matrix, into highly interconnected 3-D activated carbon nanofiber (CNF) electrodes. The ionogel exhibits strong mechanical properties with a storage modulus of 5 MPa and a high ionic conductivity of 5.7 mS cm^–1 at 25 °C. The high-surface-area CNF-based electrode (2282 m² g^–1), obtained via an electrospinning technique, exhibits hierarchical porosity generated both in situ during pyrolysis and ex situ via KOH activation. The porous architecture of the CNF electrodes facilitates the facile percolation of the soft but mechanically durable ionogel film, thereby enabling intimate contact between porous nanofibers and the gel electrolyte interface. The supercapacitor demonstrates promising capacitive characteristics, including a gravimetric capacitance of 153 F g^–1, a high specific energy density of 65 W h kg^–1, and high cycling stability, with a capacitance fade of only 4% after 20 000 charge–discharge cycles at 1 A g^–1. Moreover, device-level areal capacitances for the gel IL cell of 122 and 151 mF cm^–2 are observed at electrode mass loadings of 3.20 and 5.10 mg cm^–2, respectively

Bulk-Phase Ion Conduction in Cocrystalline LiCl·<i>N</i>,<i>N</i>‑Dimethylformamide: A New Paradigm for Solid Electrolytes Based upon the Pearson Hard–Soft Acid–Base Concept

Bulk-Phase Ion Conduction in Cocrystalline LiCl·<i>N</i>,<i>N</i>‑Dimethylformamide: A New Paradigm for Solid Electrolytes Based upon the Pearson Hard–Soft Acid–Base Concep

Bulk-Phase Ion Conduction in Cocrystalline LiCl·<i>N</i>,<i>N</i>‑Dimethylformamide: A New Paradigm for Solid Electrolytes Based upon the Pearson Hard–Soft Acid–Base Concept

Bulk-Phase Ion Conduction in Cocrystalline LiCl·<i>N</i>,<i>N</i>‑Dimethylformamide: A New Paradigm for Solid Electrolytes Based upon the Pearson Hard–Soft Acid–Base Concep