Development of Hierarchically Porous Ionomer Membranes for Versatile and Fast Metal Ion Conduction

Innovative design concepts can play a key role in the realization of high-performance ionomer membranes that are capable of exclusive metal ion conduction and potentially applicable in electrochemical devices including sensors, fuel cells, and high-energy batteries. Herein, we report on the development of new ionomers, based on sulfonated poly(ether ether ketone) (SPEEK), engineered to conduct a variety of ions, namely, Li+, Na+, K+, Zn2+, and Mg2+, when soaked with nonaqueous solvents. Application of a facile phase-inversion method results in M-SPEEK (M = Li/Na/K/Zn/Mg) membranes with a hierarchical porous network, facilitating organic solvent infusion that is necessary to promote dissociation and rapid transport of cations between anionic sulfonate groups on the polymer chains. This strategy leads to membranes with alkali ion conductivities approaching 10–4 S cm–1 at room temperature, and near unity cation transference numbers (tM+ ≥ 0.9). Furthermore, an exceptionally high Zn-ion conductivity of 10–2 S cm–1 is obtained for the water-infused Zn-SPEEK membrane. In comparison, the dense membranes demonstrate 2–3 orders of magnitude lower conductivities because of insufficient solvent infusion. Preliminary electrochemical studies with solvent-infused ionomer membranes as the electrolyte look promising.ISSN:2470-134

Nature of alkali ion conduction and reversible Na-ion storage in hybrid formate framework materials

The cost advantage of Na-ion batteries has spurred intensive research effort in the last ten years to develop reversible Na+ storage materials. While classic host materials – analogous to the Liion system – are potentially straightforward targets, sluggish Na+ diffusion in many inorganic structures limit options. In this regard, open framework inorganic-organic hybrids like metalorganic framework materials are considered as viable alternatives. Herein we introduce heterometallic formate frameworks as potential candidates for reversible Na+ storage. In a first, we present a microwave solvothermal strategy for rapid synthesis of phase pure microcrystalline Na2Co(HCO2)4 and AB(HCO2)3 (A: Li/Na; B: Co/Mn). By combining indepth impedance analysis with ab-initio molecular dynamics simulation, we reveal that the Li+ /Na+ conduction – which follows a ‘pinball’ mechanism – in these materials is extrinsic defect dominated. Calculation suggests that a librational motion of the formate anions facilitates the diffusion of Na+ compared to Li+ , explaining the origin of anomalously higher ionic conductivity for the Na analogue compared to the Li one. Preliminary electrochemical investigation reveals reversible Na+ storage in Na2Co(HCO2)4 and NaMn(HCO2)3 at an average voltage of 2.5-3 V.Peer ReviewedPostprint (author's final draft

Nanoscale Heterostructures with Molecular-Scale Single-Crystal Metal Wires

Creating nanoscale heterostructures with molecular-scale (<2 nm) metal wires is critical for many applications and remains a challenge. Here, we report the first time synthesis of nanoscale heterostructures with single-crystal molecular-scale Au nanowires attached to different nanostructure substrates. Our method involves the formation of Au nanoparticle seeds by the reduction of rocksalt AuCl nanocubes heterogeneously nucleated on the Substrates and subsequent nanowire growth by oriented attachment of Au nanoparticles from the Solution phase. Nanoscale heterostructures fabricated by such site-specific nucleation and growth are attractive for many applications including nanoelectronic device wiring, catalysis, and sensing

Oxide versus Nonoxide Cathode Materials for Aqueous Zn Batteries: An Insight into the Charge Storage Mechanism and Consequences Thereof

Aqueous Zn-ion batteries, which are being proposed as large-scale energy storage solutions because of their unparalleled safety and cost advantage, are composed of a positive host (cathode) material, a metallic zinc anode, and a mildly acidic aqueous electrolyte (pH approximate to 3-7). Typically, the charge storage mechanism is believed to be reversible Zn2+ (de)intercalation in the cathode host, with the exception of alpha-MnO2, for which multiple vastly different and contradicting mechanisms have been proposed. However, our present study, combining electrochemical, operando X-ray diffraction, electron microscopy in conjunction with energy-dispersive X-ray spectroscopy, and in situ pH evolution analyses on two oxide hosts-tunneled alpha-MnO2 and layered V3O7 center dot H2O vis-a-vis two nonoxide hosts-layered VS2 and tunneled Zn-3[Fe(CN)(6)](2), suggests that oxides and nonoxides follow two dissimilar charge storage mechanisms. While the oxides behave as dominant proton intercalation materials, the nonoxides undergo exclusive zinc intercalation. Stabilization of H+ on the hydroxyl-terminated oxide surface is revealed to facilitate the proton intercalation by a preliminary molecular dynamics simulation study. Proton intercalation for both oxides leads to the precipitation of layered double hydroxide (LDH)-Zn4SO4(OH)(6)center dot 5H(2)O with a ZnSO4/H2O electrolyte and a triflate anion (CF3SO3-)-based LDH with a Zn(SO3CF3)(2)/H2O electrolyte-on the electrode surface. The LDH precipitation buffers the pH of the electrolytes to a mildly acidic value, sustaining the proton intercalation to deliver large specific capacities for the oxides. Moreover, we also show that the stability of the LDH precipitate is crucial for the rechargeability of the oxide cathodes, revealing a critical link between the charge storage mechanism and the performance of the oxide hosts in aqueous zinc batteries

Bottom-Up Design of a Green and Transient Zinc-Ion Battery with Ultralong Lifespan

Transient batteries are expected to lessen the inherent environmental impact of traditional batteries that rely on toxic and critical raw materials. This work presents the bottom-up design of a fully transient Zn-ion battery (ZIB) made of nontoxic and earth-abundant elements, including a novel hydrogel electrolyte prepared by cross-linking agarose and carboxymethyl cellulose. Facilitated by a high ionic conductivity and a high positive zinc-ion species transference number, the optimized hydrogel electrolyte enables stable cycling of the Zn anode with a lifespan extending over 8500 h for 0.25 mA cm−2 – 0.25 mAh cm−2. On pairing with a biocompatible organic polydopamine-based cathode, the full cell ZIB delivers a capacity of 196 mAh g−1 after 1000 cycles at a current density of 0.5 A g−1 and a capacity of 110 mAh g−1 after 10 000 cycles at a current density of 1 A g−1. A transient ZIB with a biodegradable agarose casing displays an open circuit voltage of 1.123 V and provides a specific capacity of 157 mAh g−1 after 200 cycles at a current density of 50 mA g−1. After completing its service life, the battery can disintegrate under composting conditions.ISSN:1613-6810ISSN:1613-682

Favorable Interfacial Chemomechanics Enables Stable Cycling of High-Li-Content Li–In/Sn Anodes in Sulfide Electrolyte-Based Solid-State Batteries

10.1021/acs.chemmater.1c01431Chemistry of Material

A Highly Active Low Voltage Redox Mediator for Enhanced Rechargeability of Lithium–Oxygen Batteries

Owing to its high theoretical specific energy, the Li-oxygen battery is one of the fundamentally most promising energy storage systems, but also one of the most challenging. Poor rechargeability, involving the oxidation of insoluble and insulating lithium peroxide (Li₂O₂), has remained the “Achilles’ heel” of this electrochemical energy storage system. We report here on a new redox mediator tris­[4-(diethylamino)­phenyl]­amine (TDPA), thatat 3.1 Vexhibits the lowest and closest potential redox couple compared to the equilibrium voltage of the Li-oxygen cell of those reported to date, with a second couple also at a low potential of 3.5 V. We show it is a soluble “catalyst” capable of lowering the Li₂O₂ charging potential by >0.8 V without requiring direct electrical contact of the peroxide and that it also facilitates high discharge capacities. Its chemical and electrochemical stability, fast diffusion kinetics, and two dynamic redox potentials represent a significant advance in oxygen-evolution catalysis. It enables Li–O₂ cells that can be recharged more than 100 cycles with average round-trip efficiencies >80%, opening a new avenue for practical Li-oxygen batteries

A low dimensional composite of hexagonal lithium manganese borate (LiMnBO3), a cathode material for Li-ion batteries

The ultrasonic nebulized spray pyrolysis technique has been applied to synthesize amorphous nanospheres, which are further transformed into nano h-LiMnBO3 with an average crystallite size of [similar]14 nm. A composite electrode of nano h-LiMnBO3 with reduced graphite oxide and amorphous carbon delivers a high first discharge capacity of 140 mA h g−1 at C/15 rate within 4.5–2.0 V and retains a discharge capacity of 110 mA h g−1 at the 25th cycle. The dissolution of Mn into the electrolyte and the instability of the highly delithiated phases during cycling are suggested as the reasons, which limit the cycling stability of h-LiMnBO3. An improved cycling stability at higher capacities is expected via the combination of the particle size reduction, conductive network formation and the metal site doping strategies

The Natural Antisense Transcript DONE40 Derived from the lncRNA ENOD40 Locus Interacts with SET Domain Protein ASHR3 During Inception of Symbiosis in Arachis hypogaea

International audienceThe long noncoding RNA ENOD40 is required for cortical cell division during root nodule symbiosis (RNS) of legumes, though it is not essential for actinorhizal RNS. Our objective was to understand whether ENOD40 was required for aeschynomenoid nodule formation in Arachis hypogaea. AhENOD40 express from chromosome 5 (chr5) (AhENOD40-1) and chr15 (AhENOD40-2) during symbiosis, and RNA interference of these transcripts drastically affected nodulation, indicating the importance of ENOD40 in A. hypogaea. Furthermore, we demonstrated several distinct characteristics of ENOD40. (i) Natural antisense transcript (NAT) of ENOD40 was detected from the AhENOD40-1 locus (designated as NAT-AhDONE40). (ii) Both AhENOD40-1 and AhENOD40-2 had two exons, whereas NAT-AhDONE40 was monoexonic. Reverse-transcription quantitative PCR analysis indicated both sense and antisense transcripts to be present in both cytoplasm and nucleus, and their expression increased with the progress of symbiosis. (iii) RNA pull-down from whole cell extracts of infected roots at 4 days postinfection indicated NAT-AhDONE40 to interact with the SET (Su(var)3-9, enhancer of Zeste and Trithorax) domain containing absent small homeotic disc (ASH) family protein AhASHR3 and this interaction was further validated using RNA immunoprecipitation and electrophoretic mobility shift assay. (iv) Chromatin immunoprecipitation assays indicate deposition of ASHR3-specific histone marks H3K36me3 and H3K4me3 in both of the ENOD40 loci during the progress of symbiosis. ASHR3 is known for its role in optimizing cell proliferation and reprogramming. Because both ASHR3 and ENOD40 from legumes cluster away from those in actinorhizal plants and other nonlegumes in phylogenetic distance trees, we hypothesize that the interaction of DONE40 with ASHR3 could have evolved for adapting the nodule organogenesis program for legumes. [Formula: see text] Copyright © 2021 The Author(s). This is an open access article distributed under the CC BY-NC-ND 4.0 International license