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Polymer based electrolyte shows advantages in compatibly improving safety and interface stability of batteries, while its limited ion conductivity and transfer number make it difficult to apply in batteries with high energy density. Herein, by designing four crosslinking polyesters with different electron withdrawing group (EWG), it is found that strengthening the binding of EWG to anion for weakening the binding of anion to Li+ is critical for high Li+ transfer number ( tLi+ ${t_{Li}^+ }$ ) and ionic conductivity of electrolyte. As a result, poly (2,2,3,3‐tetrafluoropropyl methacrylate) (PTFM) based gel polymer electrolyte (GPE) shows an ionic conductivity of 0.78 mS cm−1 and a tLi+ ${{t}_{Li}^{+}}$ of 0.85, much higher than those of poly (methyl methacrylate) (PMMA) without EWG. Moreover, PTFM based GPE shows excellent flame retardancy property. Li||PTFM||NCM811 batteries with an ultrahigh capacity of 5.5 mAh cm−2 show stable cycles of 5 times to that of Li||PMMA||NCM811. Moreover, the assembled graphite||PTFM||NCM811 pouch cell shows a capacity retention rate of 92 % after 500 cycles. This work clarifies the mechanism of cation/anion interaction on ionic conductivity of GPE, which is important to develop high‐performance devices with good safety and flexibility. [ABSTRACT FROM AUTHOR]

Defect-engineering accelerates the conduction of lithium ions in the cathode materials of lithium-ion batteries. However, the effects of defect-engineering on ion conduction and its mechanisms in humid environments remain unclear in the academic discourse. Here, we report on the effect of vacancy defects on the electronic properties of and Li-ion diffusion in a LiFePO4 material in humid environments. The research findings indicate that vacancy defects reduce the lattice constant and unit cell volume of LiFePO4. Additionally, the water molecules occupy the Li-ion vacancies, leading to an increase in the lattice constant of LiFePO4. The computational results of the electronic properties show that the introduction of water molecules induces a transition in LiFePO4 from a semiconductor to a metallic behavior, with a transfer of 0.38 e of charge from the water molecules to LiFePO4. Additionally, the migration barrier for Li ions in the H2O + LiFePO4 system is found to be 0.50 eV, representing an 11.1% increase compared to the pristine LiFePO4 migration barrier. Our findings suggest that water molecules impede the migration of Li ions and provide important insights into the effect of defect-engineering on electronic properties and ion conduction under humid conditions. [ABSTRACT FROM AUTHOR]

Photolithography has been the foundational fabrication paradigm in current high‐performance electronics. However, due to the limitation in fabrication resolution, scaling beyond a 20‐nm critical dimension for metal conductors presents a significant challenge for photolithography. Structural DNA nanotechnology emerges as a promising alternative to photolithography, allowing for the site‐specific assembly of nano‐materials at single‐molecule resolution. Substantial progresses have been achieved in the ultra‐scaled DNA‐based conductors, exhibiting novel transport characteristics and small critical dimensions. This review highlights the structure‐transport property relationship for various DNA‐based conductors and their potential applications in quantum /semiconductor electronics, going beyond the conventional scope focusing mainly on the shape diversity of DNA‐templated metals. Different material synthesis methods and their morphological impacts on the conductivities are discussed in detail, with particular emphasis on the conducting mechanisms, such as insulating, metallic conducting, quantum tunneling, and superconducting. Furthermore, the ionic gating effect of self‐assembled DNA structures in electrolyte solutions is examined. This review also suggests potential solutions to address current challenges in DNA‐based conductors, encouraging multi‐disciplinary collaborations for the future development of this exciting area. [ABSTRACT FROM AUTHOR]

Ionic discotic liquid crystals combine ion conduction with fluid, yet ordered, liquid crystal phases at ambient temperature, making them suitable nanomaterials for ion transport and energy storage. A series of Janus-type hexa-peri-hexabenzocoronenes (HBCs) with ionic (sulfonate) groups covalently bonded to the HBC core, and tetraalkylammonium counterions (sizes from 0.15 to 0.95 nm) are synthesized and investigated with respect to the self-assembly and ion dynamics. We find that the counterion size affects the nanoscale self-assembly and ionic conductivity in opposite ways. Smaller counterions act as structure formers, whereas larger ones act as structure breakers. The latter exhibits the highest ion dc-conductivity. We quantify the effect of Coulomb interactions on the self-assembly, the glass temperature Tg (which was found to vary by 30 K), and the dc-conductivity (varying by 4 orders of magnitude). The precise synthesis of tailor-made ionic discotic liquid crystals with the HBC core and the characterization of their physical properties revealed that ion-conduction and nanoscale self-assembly in HBCs can be modulated by tuning electrostatic interactions, e.g., by adjusting the size of counterions. [ABSTRACT FROM AUTHOR]

Many voltage-gated potassium (Kv) channels display a time-dependent phenomenon called C-type inactivation, whereby prolonged activation by voltage leads to the inhibition of ionic conduction, a process that involves a conformational change at the selectivity filter toward a non-conductive state. Recently, a high-resolution structure of a strongly inactivated triple-mutant channel kv1.2-kv2.1-3m revealed a novel conformation of the selectivity filter that is dilated at its outer end, distinct from the well-characterized conductive state. While the experimental structure was interpreted as the elusive non-conductive state, our molecular dynamics simulations and electrophysiological measurements show that the dilated filter of kv1.2-kv2.1-3m is conductive and, as such, cannot completely account for the inactivation of the channel observed in the structural experiments. The simulation shows that an additional conformational change, implicating isoleucine residues at position 398 along the pore lining segment S6, is required to effectively block ion conduction. The I398 residues from the four subunits act as a state-dependent hydrophobic gate located immediately beneath the selectivity filter. These observations are corroborated by electrophysiological experiments showing that ion permeation can be resumed in the kv1.2-kv2.1-3m channel when I398 is mutated to an asparagine—a mutation that does not abolish C-type inactivation since digitoxin (AgTxII) fails to block the ionic permeation of kv1.2-kv2.1-3m_I398N. As a critical piece of the C-type inactivation machinery, this structural feature is the potential target of a broad class of quaternary ammonium (QA) blockers and negatively charged activators thus opening new research directions toward the development of drugs that specifically modulate gating states of Kv channels.

Na1.36(Si0.86Ga0.14)2As2.98 and Li1.5Ga0.9Si3.1As4 were synthesized by heating mixtures of the elements at 950 °C. The crystal structures were determined by single crystal X-ray diffraction (Na1.36(Si0.86Ga0.14)2As2.98: I41/a, Z = 100, a = 19.8772(4) Å, c = 37.652(1) Å; Li1.5Ga0.9Si3.1As4: C2/c, Z = 8, a = 10.8838(6) Å, b = 10.8821(6) Å, c = 13.1591(7) Å). Na1.36(Si0.86Ga0.14)2As2.98 crystallizes similar to NaSi2P3 with interpenetrating networks of vertex-sharing T4 and T5 supertetrahedra. Gallium substitution at the silicon sites increases the charge of the cluster network, which is compensated for by a 36% higher sodium content. Since in contrast to NaSi2P3, all sodium sites are now fully occupied, there is no significant ion mobility, as indicated by 23Na-NMR. Consequently, the total sodium-ion conductivity of Na1.36(Si0.86Ga0.14)2As2.98 amounts to only 1.6(1) × 10−7 S cm−1 and is therefore three orders of magnitude lower than in NaSi2P3. Li1.5Ga0.9Si3.1As4 crystallizes in a new structure type with layers of edge-sharing (Si1−xGax)As4 tetrahedra alternating with layers that contain infinite Sin zigzag chains. Lithium ions reside in channels between the chains, and thus, the structure does not provide three dimensional pathways for ion conduction and the measured total Li-ion conductivity amounts to only 1.3(1) × 10−7 S cm−1. [ABSTRACT FROM AUTHOR]

Electrohydrodynamic (EHD) conduction pumping can be applied in many macroscopic devices accompanied by a high electric field intensity (106 V/m). Microscale flow generation has become increasingly important with the widespread development of thermal management devices, which are currently used to cool high heat flux sources with small surface areas and are found in a variety of electronic, controlled heat transfer, and aerospace scenarios. Additionally, the magnitude of the applied voltage can be significantly reduced in micropumping, resulting in power savings and a reliable method for flow generation. In this study, we examine the dynamic characteristics of a conduction micropump embedded within a rectangular microchannel, showing the effects of Coulombic driving forces, different channel heights, polymer elasticity, and viscosity ratios. The results show that electric power consumption can vary by two orders of magnitude for increasing channel height. As the polymer concentration increases, the maximum velocity decreases significantly and can reach 50% of that of the unadded polymer with a plunger-like distribution. The flow rate depends linearly on the polymer concentration, but exhibits non-monotonic curve with the polymer elasticity. It means that the flow rate performance of the micro-pump can be kept controllable by tuning the viscosity ratio, providing some suggestions for some regulated flow applications. [ABSTRACT FROM AUTHOR]

The quaternary phosphidosilicates AE2Li4SiP4 (AE=Ca, Sr, Eu) and Ba4Li16Si3P12 were synthesized by heating the elements and Li3P under argon atmosphere. Their crystal structures were determined by single crystal X‐ray diffraction. AE2Li4SiP4 crystallize in a new layered structure type (P21/m, Z=2) with CdI2‐analoguos layers. Edge sharing CaP6 octahedra are separated by layers of vertex‐sharing SiP4 and LiP4 tetrahedra, which contain additional chains of LiP6 octahedra. Ba4Li16Si3P12 forms likewise a new structure type (P21/c, Z=16) with a three‐dimensional network of SiP4, Si2P6 and LiP4 entities as well as one phosphorus site not bonded to silicon. Barium is located in capped trigonal prisms of phosphorus which form strongly corrugated layers. 31P and 29Si solid‐state NMR spectra confirm the crystal structures of the compounds AE2Li4SiP4. 7Li spectra show only one signal in spite of quite different crystallographic positions, which indicate possible Li+ mobility. However, this signal is much broader compared to the known Li+ conducting phosphidosilicates. Accordingly, electrochemical impedance measurements show low Li+ conductivities. [ABSTRACT FROM AUTHOR]

The quaternary phosphidosilicates AE2Li4SiP4 (AE=Ca, Sr, Eu) and Ba4Li16Si3P12 were synthesized by heating the elements and Li3P under argon atmosphere. Their crystal structures were determined by single crystal X‐ray diffraction. AE2Li4SiP4 crystallize in a new layered structure type (P21/m, Z=2) with CdI2‐analoguos layers. Edge sharing CaP6 octahedra are separated by layers of vertex‐sharing SiP4 and LiP4 tetrahedra, which contain additional chains of LiP6 octahedra. Ba4Li16Si3P12 forms likewise a new structure type (P21/c, Z=16) with a three‐dimensional network of SiP4, Si2P6 and LiP4 entities as well as one phosphorus site not bonded to silicon. Barium is located in capped trigonal prisms of phosphorus which form strongly corrugated layers. 31P and 29Si solid‐state NMR spectra confirm the crystal structures of the compounds AE2Li4SiP4. 7Li spectra show only one signal in spite of quite different crystallographic positions, which indicate possible Li+ mobility. However, this signal is much broader compared to the known Li+ conducting phosphidosilicates. Accordingly, electrochemical impedance measurements show low Li+ conductivities. [ABSTRACT FROM AUTHOR]

LixMoS2 is not only a lithium battery material, but is also an important precursor for the synthesis of MoS2 nanomaterials. Current syntheses of MoS2, such as in n‐butyllithium/LiBH4 or electrochemically, are not satisfying in terms of defined stoichiometry and crystallinity, so an accurate experimental crystal structure determination of this important and widely used material has been long awaited. A high‐pressure/high‐temperature synthesis yielded highly crystalline 1T′′‐LixMoS2 (x=1, 1.333). 1T′′‐LiMoS2 crystallizes in the space group P1‾ $\bar 1$ with a=6.2482(3) Å, b=6.6336(3) Å, c=6.7480(3) Å, α=119.321(2)°, β=90.010(2)° and γ=90.077(2)°. The arrangement of Mo atoms within the b‐c‐plane confirmed a predicted Peierls distortion. A similar atom distribution pattern to that of Mo is also observed for the lithium atoms. Calculation of bond valence site energies gave an activation barrier of 1.244 eV for 2D lithium‐ion migration. For x=1.333, a phase‐pure synthesis was achieved. [ABSTRACT FROM AUTHOR]

LixMoS2 is not only a lithium battery material, but is also an important precursor for the synthesis of MoS2 nanomaterials. Current syntheses of MoS2, such as in n‐butyllithium/LiBH4 or electrochemically, are not satisfying in terms of defined stoichiometry and crystallinity, so an accurate experimental crystal structure determination of this important and widely used material has been long awaited. A high‐pressure/high‐temperature synthesis yielded highly crystalline 1T′′‐LixMoS2 (x=1, 1.333). 1T′′‐LiMoS2 crystallizes in the space group P1‾ $\bar 1$ with a=6.2482(3) Å, b=6.6336(3) Å, c=6.7480(3) Å, α=119.321(2)°, β=90.010(2)° and γ=90.077(2)°. The arrangement of Mo atoms within the b‐c‐plane confirmed a predicted Peierls distortion. A similar atom distribution pattern to that of Mo is also observed for the lithium atoms. Calculation of bond valence site energies gave an activation barrier of 1.244 eV for 2D lithium‐ion migration. For x=1.333, a phase‐pure synthesis was achieved. [ABSTRACT FROM AUTHOR]

Defect-engineering accelerates the conduction of lithium ions in the cathode materials of lithium-ion batteries. However, the effects of defect-engineering on ion conduction and its mechanisms in humid environments remain unclear in the academic discourse. Here, we report on the effect of vacancy defects on the electronic properties of and Li-ion diffusion in a LiFePO4 material in humid environments. The research findings indicate that vacancy defects reduce the lattice constant and unit cell volume of LiFePO4. Additionally, the water molecules occupy the Li-ion vacancies, leading to an increase in the lattice constant of LiFePO4. The computational results of the electronic properties show that the introduction of water molecules induces a transition in LiFePO4 from a semiconductor to a metallic behavior, with a transfer of 0.38 e of charge from the water molecules to LiFePO4. Additionally, the migration barrier for Li ions in the H2O + LiFePO4 system is found to be 0.50 eV, representing an 11.1% increase compared to the pristine LiFePO4 migration barrier. Our findings suggest that water molecules impede the migration of Li ions and provide important insights into the effect of defect-engineering on electronic properties and ion conduction under humid conditions.

Na1.36(Si0.86Ga0.14)2As2.98 and Li1.5Ga0.9Si3.1As4 were synthesized by heating mixtures of the elements at 950 °C. The crystal structures were determined by single crystal X-ray diffraction (Na1.36(Si0.86Ga0.14)2As2.98: I41/a, Z = 100, a = 19.8772(4) Å, c = 37.652(1) Å; Li1.5Ga0.9Si3.1As4: C2/c, Z = 8, a = 10.8838(6) Å, b = 10.8821(6) Å, c = 13.1591(7) Å). Na1.36(Si0.86Ga0.14)2As2.98 crystallizes similar to NaSi2P3 with interpenetrating networks of vertex-sharing T4 and T5 supertetrahedra. Gallium substitution at the silicon sites increases the charge of the cluster network, which is compensated for by a 36% higher sodium content. Since in contrast to NaSi2P3, all sodium sites are now fully occupied, there is no significant ion mobility, as indicated by 23Na-NMR. Consequently, the total sodium-ion conductivity of Na1.36(Si0.86Ga0.14)2As2.98 amounts to only 1.6(1) × 10−7 S cm−1 and is therefore three orders of magnitude lower than in NaSi2P3. Li1.5Ga0.9Si3.1As4 crystallizes in a new structure type with layers of edge-sharing (Si1−xGax)As4 tetrahedra alternating with layers that contain infinite Sin zigzag chains. Lithium ions reside in channels between the chains, and thus, the structure does not provide three dimensional pathways for ion conduction and the measured total Li-ion conductivity amounts to only 1.3(1) × 10−7 S cm−1.

Sodium‐ion battery is a potential application system for large‐scale energy storage due to the advantage of higher nature abundance and lower production cost of sodium‐based materials. However, there exist inevitably the safety problems such as flammability due to the use of the same type of organic liquid electrolyte with lithium‐ion battery. Gel polymer electrolytes are being considered as an effective solution to replace conventional organic liquid electrolytes for building safer sodium‐ion batteries. In this review paper, the authors present a comprehensive overview of the research progress in electrochemical and physical properties of the gel polymer electrolyte‐based sodium batteries. The gel polymer electrolytes based on different polymer hosts namely poly(ethylene oxide), poly(acrylonitrile), poly(methyl methacrylate), poly(vinylidene fluoride), poly(vinylidene fluoride‐hexafluoro propylene), and other new polymer networks are summarized. The ionic conductivity, ion transference number, electrochemical window, thermal stability, mechanical property, and interfacial issue with electrodes of gel polymer electrolytes, and the corresponding influence factors are described in detail. Furthermore, the ion transport pathway and ion conduction mechanism are analyzed and discussed. In addition, the advanced gel polymer electrolyte systems including flame‐retardant polymer electrolytes, composite gel polymer electrolytes, copolymerization, single‐ion conducting polymer electrolytes, etc. with more superior and functional performance are classified and summarized. Finally, the application prospects, development opportunities, remaining challenges, and possible solutions are discussed. [ABSTRACT FROM AUTHOR]

Sodium‐ion batteries (SIBs) are expected to become alternatives to lithium‐ion batteries (LIBs) as next‐generation rechargeable batteries, owing to abundant sodium sources and low cost. However, SIBs still use liquid organic electrolytes (LOEs), which are highly flammable and have the tendency to leak. Although inorganic solid electrolytes (ISEs) and solid polymer electrolytes (SPEs) have been investigated for many years, given their higher safety level, neither of them is likely to be commercialized because of the rigidity of ISEs and the low room‐temperature ionic conductivity of SPEs. During the last decade, composite polymer electrolytes (CPEs), composed of ISEs and SPEs, exhibiting both relatively high ionic conductivity and flexibility, have gained much attention and are considered as promising electrolytes. However, the ionic conductivities of CPEs are still unsatisfactory for practical application. Hence, this Review focuses on the principle of sodium ion conductors and particularly on recent investigations and development of CPEs. [ABSTRACT FROM AUTHOR]

Organic‐inorganic composite solid electrolytes consisting of garnet fillers dispersed in polyvinylidene difluoride (PVDF) frameworks have shown promise to enable high‐energy solid‐state Li‐metal batteries. However, the air‐sensitive garnets easily form poorly‐conductive residues, which hinders fast Li‐ion exchange at the garnet‐polymer interface and results in low ionic conductivity. The highly alkaline residues trigger instant dehydrofluorination of PVDF to form unsaturated CC bonds, which are unstable against high‐voltage cathode materials. Here it is shown that, by applying a 10‐nm polydopamine coating on the residue‐removed garnet surface, the modified garnet filler becomes air‐stable and does not generate alkaline residues, so PVDF remains an intact structure. Surface characterizations reveal substantial metal‐nitrogen bonding between the La atoms of garnet and the amino groups of polydopamine, which can invite stronger adsorption of Li ions at the heterointerface. A new interparticle Li‐ion conduction mechanism is disclosed for the composite electrolyte, in which Li ions preferably migrate through the garnet‐polydopamine interface, forming an efficient ion‐percolation network. As a result, the composite electrolyte demonstrates an effective room‐temperature Li+ conductivity of 1.52 × 10–4 S cm–1 and a high cutoff voltage of up to 4.7 V versus Li+/Li to support stable operation of all‐solid‐state Li‐LiCoO2 batteries. [ABSTRACT FROM AUTHOR]

All‐solid‐state batteries are promising candidates for safe energy‐storage systems due to non‐flammable solid electrolytes and the possibility to use metallic lithium as an anode. Thus, there is a challenge to design new solid electrolytes and to understand the principles of ion conduction on an atomic scale. We report on a new concept for compounds with high lithium ion mobility based on a rigid open‐framework boron structure. The host–guest structure Li6B18(Li3N) comprises large hexagonal pores filled with ∞1[ ${{}_{{\rm { \infty }}}{}^{{\rm { 1}}}{\rm { [}}}$ Li7N] strands that represent a perfect cutout from the structure of α‐Li3N. Variable‐temperature 7Li NMR spectroscopy reveals a very high Li mobility in the template phase with a remarkably low activation energy below 19 kJ mol−1 and thus much lower than pristine Li3N. The formation of the solid solution of Li6B18(Li3N) and Li6B18(Li2O) over the complete compositional range allows the tuning of lithium defects in the template structure that is not possible for pristine Li3N and Li2O. [ABSTRACT FROM AUTHOR]

All‐solid‐state batteries are promising candidates for safe energy‐storage systems due to non‐flammable solid electrolytes and the possibility to use metallic lithium as an anode. Thus, there is a challenge to design new solid electrolytes and to understand the principles of ion conduction on an atomic scale. We report on a new concept for compounds with high lithium ion mobility based on a rigid open‐framework boron structure. The host–guest structure Li6B18(Li3N) comprises large hexagonal pores filled with ∞1[ ${{}_{{\rm { \infty }}}{}^{{\rm { 1}}}{\rm { [}}}$ Li7N] strands that represent a perfect cutout from the structure of α‐Li3N. Variable‐temperature 7Li NMR spectroscopy reveals a very high Li mobility in the template phase with a remarkably low activation energy below 19 kJ mol−1 and thus much lower than pristine Li3N. The formation of the solid solution of Li6B18(Li3N) and Li6B18(Li2O) over the complete compositional range allows the tuning of lithium defects in the template structure that is not possible for pristine Li3N and Li2O. [ABSTRACT FROM AUTHOR]

All‐solid‐state batteries are promising candidates for safe energy‐storage systems due to non‐flammable solid electrolytes and the possibility to use metallic lithium as an anode. Thus, there is a challenge to design new solid electrolytes and to understand the principles of ion conduction on an atomic scale. We report on a new concept for compounds with high lithium ion mobility based on a rigid open‐framework boron structure. The host–guest structure Li6B18(Li3N) comprises large hexagonal pores filled with ∞1[ ${{}_{{\rm { \infty }}}{}^{{\rm { 1}}}{\rm { [}}}$ Li7N] strands that represent a perfect cutout from the structure of α‐Li3N. Variable‐temperature 7Li NMR spectroscopy reveals a very high Li mobility in the template phase with a remarkably low activation energy below 19 kJ mol−1 and thus much lower than pristine Li3N. The formation of the solid solution of Li6B18(Li3N) and Li6B18(Li2O) over the complete compositional range allows the tuning of lithium defects in the template structure that is not possible for pristine Li3N and Li2O. [ABSTRACT FROM AUTHOR]

Solid‐state electrolytes have attracted considerable attention in new energy‐related devices due to their high safety and broad application platform. Polyoxometalates (POMs) are a kind of molecular‐level cluster compounds with unique structures. In recent years, owing to their abundant physicochemical properties (including high ionic conductivity and reversible redox activity), POMs have shown great potential in becoming a new generation of solid‐state electrolytes. In this review, an overview is investigated about how POMs have evolved as ion‐conducting materials from basic research to novel solid‐state electrolytes in energy devices. First, some expressive POM‐based ion‐conducting materials in recent years are introduced and classified, mainly inspecting their structural and functional relationship. After that, it is further focused on the application of these ion‐conducting electrolytes in the fields of proton exchange membranes, supercapacitors, and ion batteries. In addition, some properties of POMs (such as inherent dimension, capable of forming stable hydrogen bonds, and reversible bonding to water molecules) enable these functional POM‐based electrolytes to be employed in innovative applications such as ion selection, humidity sensing, and smart materials. Finally, some fundamental recommendations are given on the current opportunities and challenges of POM‐based ion‐conducting electrolytes. [ABSTRACT FROM AUTHOR]

All‐solid‐state batteries are promising candidates for safe energy‐storage systems due to non‐flammable solid electrolytes and the possibility to use metallic lithium as an anode. Thus, there is a challenge to design new solid electrolytes and to understand the principles of ion conduction on an atomic scale. We report on a new concept for compounds with high lithium ion mobility based on a rigid open‐framework boron structure. The host–guest structure Li6B18(Li3N) comprises large hexagonal pores filled with ∞1[ ${{}_{{\rm { \infty }}}{}^{{\rm { 1}}}{\rm { [}}}$ Li7N] strands that represent a perfect cutout from the structure of α‐Li3N. Variable‐temperature 7Li NMR spectroscopy reveals a very high Li mobility in the template phase with a remarkably low activation energy below 19 kJ mol−1 and thus much lower than pristine Li3N. The formation of the solid solution of Li6B18(Li3N) and Li6B18(Li2O) over the complete compositional range allows the tuning of lithium defects in the template structure that is not possible for pristine Li3N and Li2O. [ABSTRACT FROM AUTHOR]

Biological ion channels penetrated through cell membrane form unique transport pathways for selective ionic conductance. Replicating the success of ion selectivity with mixed matrix membranes (MMMs) will enable new separation technologies but remains challenging. Herein, we report a soft substrate‐assisted solution casting method to develop MMMs with penetrating subnanochannels for selective metal ion conduction. The MMMs are composed of penetrating Prussian white (PW) microcubes with subnanochannels in dense polyimide (PI) matrices, achieving selective monovalent metal ion conduction. The ion selectivity of K+/Mg2+ is up to 14.0, and the ion conductance of K+ can reach 45.5 μS with the testing diameter of 5 mm, which can be further improved by increasing the testing area. Given the diversity of nanoporous materials and polymer matrices, we expect that the MMMs with penetrating subnanochannels could be developed into a versatile nanofluidic platform for various emerging applications. [ABSTRACT FROM AUTHOR]

Developing laminar composite solid electrolyte with ultrathin thickness and continuous conduction channels in vertical direction holds great promise for all‐solid‐state lithium batteries. Herein, a thin, laminar solid electrolyte is synthesized by filtrating –NH2 functionalized metal‐organic framework nanosheets and then being threaded with poly(ethylene oxide) chains induced by the hydrogen‐bonding interaction from –NH2 groups. It is demonstrated that the threaded poly(ethylene oxide) chains lock the adjacent metal‐organic framework nanosheets, giving highly enhanced structural stability (Young's modulus, 1.3 GPa) to 7.5‐μm‐thick laminar composite solid electrolyte. Importantly, these poly(ethylene oxide) chains with stretching structure serve as continuous conduction pathways along the chains in pores. It makes the non‐conduction laminar metal‐organic framework electrolyte highly conductive: 3.97 × 10−5 S cm−1 at 25 °C, which is even over 25 times higher than that of pure poly(ethylene oxide) electrolyte. The assembled lithium cell, thus, acquires superior cycling stability, initial discharge capacity (148 mAh g−1 at 0.5 C and 60 °C), and retention (94% after 150 cycles). Besides, the pore size of nanosheet is tailored (24.5–40.9 Å) to evaluate the mechanisms of chain conformation and ion transport in confined space. It shows that the confined pore only with proper size could facilitate the stretching of poly(ethylene oxide) chains, and meanwhile inhibit their disorder degree. Specifically, the pore size of 33.8 Å shows optimized confinement effect with trans‐poly(ethylene oxide) and cis‐poly(ethylene oxide) conformation, which offers great significance in ion conduction. Our design of poly(ethylene oxide)‐threaded architecture provides a platform and paves a way to the rational design of next‐generation high‐performance porous electrolytes. [ABSTRACT FROM AUTHOR]

In this study, multi-walled carbon nanotubes (MWCNTs) were incorporated as functional fillers into bitumen emulsion, along with self-sensing cementitious sensors, to investigate their internal curing and ion conduction. The mechanical properties, piezoresistivity, moisture content, and internal curing of cementitious sensors were analysed under different MWCNTs and water contents. Isothermal Calorimetry (IC), Nuclear Magnetic Resonance (NMR), Thermogravimetric Analysis (TGA), and Inductively Coupled Plasma (ICP) methods were employed to supplement the findings and unveil the mechanism. The compressive strength of bitumen-cement mortars was found to be comparable to that of the counterpart cement mortars. The results confirmed that bitumen emulsion improved the piezoresistivity due to the increased water content in the mortars and the influence of micro-holes. Additionally, the bitumen emulsion limited the moisture loss, leading to improved internal curing. The piezoresistivity was observed to be affected by ion conduction, which in return was influenced by water content. Moreover, as water content of self-sensing mortar decreased, the piezoresistivity initially increased and then decreased, flowing the moisture loss rate. These outcomes can offer insights into the performance of self-sensing bitumen cementitious sensors and their potential application in traffic condition detection and road health monitoring. [ABSTRACT FROM AUTHOR]

In this communication, we demonstrate the electrical detection of SARS-CoV-2 RNA at low femtomolar concentrations without labels or amplification reactions. Following its extraction from virus particles, the viral RNA was electrokinetically preconcentrated (100-fold) within a packed bed of probe-modified microbeads. This preconcentration was accomplished by counter-flow focusing of the RNA along an electric field gradient generated by faradaic ion concentration polarization (fICP). Hybridization of the 30 kb target RNA to the probe-modified beads sufficiently altered their surface charge to yield a measurable change in the ionic conductivity of the packed bed─a feature leveraged for electrical detection. When a single-stranded DNA probe was used, the sensitivity of this enrichment and sensing scheme was low picomolar. However, the utilization of an uncharged PNA probe improved the limit of detection to 3.4 × 10 6 viral copies/mL (22.5 fM SARS-CoV-2 RNA). These results are significant for three reasons. First, the sensitivity is remarkable, given the micrometer scale of both the beads and interstitial spaces. Additional gains in enrichment and sensitivity are anticipated as fundamental parametric studies and optimization are undertaken. Second, this study reveals the impact of the probe type on the sensitivity of microscale surface ion conduction (μSIC) sensors. Third, the RNA sensing approach has practical advantages including its utilization of off-the-shelf beads, a reagent-free approach, nonoptical readout, and low driving voltage, which render it amenable to point-of-care (POC) implementation.

Many voltage-gated potassium (Kv) channels display a time-dependent phenomenon called C-type inactivation, whereby prolonged activation by voltage leads to the inhibition of ionic conduction, a process that involves a conformational change at the selectivity filter toward a non-conductive state. Recently, a high-resolution structure of a strongly inactivated triple-mutant channel kv1.2-kv2.1-3m revealed a novel conformation of the selectivity filter that is dilated at its outer end, distinct from the well-characterized conductive state. While the experimental structure was interpreted as the elusive non-conductive state, our molecular dynamics simulations and electrophysiological measurements show that the dilated filter of kv1.2-kv2.1-3m is conductive and, as such, cannot completely account for the inactivation of the channel observed in the structural experiments. The simulation shows that an additional conformational change, implicating isoleucine residues at position 398 along the pore lining segment S6, is required to effectively block ion conduction. The I398 residues from the four subunits act as a state-dependent hydrophobic gate located immediately beneath the selectivity filter. These observations are corroborated by electrophysiological experiments showing that ion permeation can be resumed in the kv1.2-kv2.1-3m channel when I398 is mutated to an asparagine-a mutation that does not abolish C-type inactivation since digitoxin (AgTxII) fails to block the ionic permeation of kv1.2-kv2.1-3m_I398N. As a critical piece of the C-type inactivation machinery, this structural feature is the potential target of a broad class of quaternary ammonium (QA) blockers and negatively charged activators thus opening new research directions toward the development of drugs that specifically modulate gating states of Kv channels., Competing Interests: WT, YL, CB, BP, JA, RU, CC, FB, BR No competing interests declared, (© 2024, Treptow, Liu, Bassetto et al.)

A range of protic ionic liquids (PILs) based on tri-n-alkylammonium cations and mesylate/triflate anions were incorporated into a polymer matrix to form ionogels (IGs). These systems were investigated for their thermal and electrochemical behaviour, as well as under the aspect of ion motion via PFG-NMR. The ionic conductivities of the ILs/IGs are in the range of 10‑4 - 10-3 Scm-1 at elevated temperatures and the diffusion coefficients were around 10‑11 m2s-1. Successful 3D printing of an IG with 70 wt% of IL is possible via stereolithography approaches, opening up applications in, e.g., structured ion-conductive membranes., (© 2024 Wiley‐VCH GmbH.)

All-solid-state batteries are promising candidates for the future generation of energy storage materials. An ideal solid-state electrolyte should have the advantages of excellent compatibility with electrodes and decent ionic conductivity. Nevertheless, the inherent low ionic conductivity of polyethylene oxide (PEO)-based electrolytes leads to low capacity, which significantly limits their wide commercial application. In this study, Dawson-type Li6P2Mo18O62 (LPM) or Li6P2W18O62 (LPW) was selected as lithium salt, combined with ionic liquids (ILs) with ether oxygen chains, and incorporated into a polymer matrix blended with PEO and polyvinylidene fluoride as fillers. A polymer electrolyte film with a smooth surface and uniform filler distribution was prepared using a mechanical co-blending method. The challenge of polyoxometalates as ion-conducting materials is attributed to the strong binding ability of their anion clusters to cations. One prominent benefit of this study is that the dissociation of Li+ from LPM or LPW is facilitated by ILs and relies on the ether oxygen chains in ILs for transport, yielding composites with favorable conduction properties. This study demonstrates the vast potential of polyoxometalates in the field of ionic conductivity.

Solid‐state ionic conductors are compelling alternatives to liquid electrolytes in clean energy‐harvesting and ‐storage technologies. The development of novel ionic conducting materials is one of the most critical challenges for next‐generation energy technologies. Several advancements in design strategies, synthetic approaches, conducting properties, and underlying mechanisms for ionic conducting metal–organic frameworks (MOFs) have been made over the past five years; however, despite the recent, considerable expansion of related research fields, there remains a lack of systematic overviews. Here, an extensive introduction to ionic conducting performance for MOFs with different design strategies is provided, focusing primarily on ion mobility with the aid of hydrogen‐bonding networks or solvated ionic charge. Furthermore, current theories on ion conducting mechanisms in different regimes are comprehensively summarized to provide an understanding of the underlying working principles in complex, realistic systems. Finally, challenges and future research directions at the forefront of ionic conducting MOF technologies are outlined. [ABSTRACT FROM AUTHOR]

Polyoxotantalates (POTas) are an important branch of polyoxometalates (POMs) that remain largely undeveloped compared with other members of the POM family including polyoxovanadates, polyoxotungstates, polyoxomolybdates, and polyoxoniobates. Owing to their promising applications in diverse fields such as photo/electrocatalysis, ion conduction, environmental protection, and magnetism, the development of synthetic strategies for new POTas has attracted continuous interest over the past decades. This review summarizes the current status in the development of POTas, including their synthetic methods, crystal structures, physicochemical properties, and potential applications. Additionally, synthetic challenges and prospects are also discussed. It is hoped that this review will be of reference value for the further development of POTas.

Next‐generation thermal management requires the development of low lattice thermal conductivity materials, as observed in ionic conductors. For example, thermoelectric efficiency is increased when thermal conductivity is decreased. Detrimentally, high ionic conductivity leads to thermoelectric device degradation. Battery safety and design also require an understanding of thermal transport in ionic conductors. Ion mobility, structural complexity, and anharmonicity have been used to explain the thermal transport properties of ionic conductors. However, thermal and ionic transport are rarely discussed in direct comparison. Herein, the ionic conductivity of Ag+ argyrodites is found to change by orders of magnitude without altering the thermal conductivity. Thermal conductivity measurements and two‐channel lattice dynamics modeling reveal that the majority of Ag+ vibrations have a non‐propagating diffuson‐like character, similar to amorphous materials. It is found that high ionic mobility is not a requirement for diffuson‐mediated transport. Instead, the same bonding and structural traits that can lead to fast ionic conduction also lead to diffuson‐mediated transport. Bridging the fields of solid‐state ionics and thermal transport, it is proposed that a vibrational perspective can lead to new design strategies for functional ionic conducting materials. As a first step, the authors relate the so‐called Meyer–Neldel behavior in ionic conductors to phonon occupations. [ABSTRACT FROM AUTHOR]

A solid-state polymer electrolyte membrane is formed by blending poly(vinylidene fluoride-co-hexafluoropropylene) with the synthesized copolymer of poly(methyl methacrylate-co-1-vinyl-3-butyl-imidazolium bis(trifluoromethanesulfonyl)imide, in which lithium bis(trifluoromethane)sulfonimide molecules are applied as the source of lithium ions. The accordingly formed membrane that contains 14 wt.% of P(MMA-co-VBIm-TFSI), 56 wt.% of PVDF-HFP, and 30 wt.% of LiTFSI manifests the best electrochemical properties, achieving an ionic conductivity of 1.11 × 10−4 S·cm−1 at 30 °C and 4.26 × 10−4 S·cm−1 at 80 °C, a Li-ion transference number of 0.36, and a wide electrochemical stability window of 4.7 V (vs. Li/Li+). The thus-assembled all-solid-state lithium-ion battery of LiFePO4/SPE/Li delivers a discharge specific capacity of 148 mAh·g−1 in the initial charge–discharge cycle at 0.1 C under 60 °C. The capacity retention of the cell is 95.2% after 50 cycles at 0.1 C and the Coulombic efficiency remains close to 100% during the cycling process. [ABSTRACT FROM AUTHOR]

Real-time structural changes in Na-β″-alumina were observed in situ using transmission electron microscopy (TEM) with electron beam irradiation. Na-β″-alumina has been widely investigated as a solid electrolyte material for sodium–sulfur secondary batteries owing to its high ionic conductivity. This high conductivity is known to be due to the Na+ ions on the loosely packed conduction planes of Na-β″-alumina. In the present study, we acquired real-time videos of the generation of spinel blocks caused by the conduction of Na+ ions. In addition, by observing Na extraction during electron beam irradiation, we experimentally confirmed that spinel block generation originates from the Na+ ion conduction, which has been a subject of recent debate. [ABSTRACT FROM AUTHOR]

Ion channels allow for the passage of ions across biological membranes, which is essential for the functioning of a cell. In pore loop channels the selectivity filter (SF) is a conserved sequence that forms a constriction with multiple ion binding sites. It is becoming increasingly clear that there are several conformations and dynamic states of the SF in cation channels. Here we outline specific modes of structural plasticity observed in the SFs of various pore loop channels: disorder, asymmetry, and collapse. We summarize the multiple atomic structures with varying SF conformations as well as asymmetric and more dynamic states that were discovered recently using structural biology, spectroscopic, and computational methods. Overall, we discuss here that structural plasticity within the SF is a key molecular determinant of ion channel gating behavior. [ABSTRACT FROM AUTHOR]

The energy landscape concept is increasingly valuable in understanding and unifying the structural, thermodynamic and dynamic properties of inorganic solids. We present a range of examples which include (i) structure prediction of new bulk phases including carbon nitrides, phosphorus carbides, LiMgF3 and low-density, ultra-flexible polymorphs of B2O3, (ii) prediction of graphene and related forms of ZnO, ZnS and other compounds which crystallise in the bulk with the wurtzite structure, (iii) solid solutions, (iv) understanding grossly non-stoichiometric oxides including the superionic phases of δ-Bi2O3 and BIMEVOX and the consequences for the mechanisms of ion transport in these fast ion conductors. In general, examination of the energy landscapes of disordered materials highlights the importance of local structural environments, rather than sole consideration of the average structure. [ABSTRACT FROM AUTHOR]

Ion channels allow for the passage of ions across biological membranes, which is essential for the functioning of a cell. In pore loop channels the selectivity filter (SF) is a conserved sequence that forms a constriction with multiple ion binding sites. It is becoming increasingly clear that there are several conformations and dynamic states of the SF in cation channels. Here we outline specific modes of structural plasticity observed in the SFs of various pore loop channels: disorder, asymmetry, and collapse. We summarize the multiple atomic structures with varying SF conformations as well as asymmetric and more dynamic states that were discovered recently using structural biology, spectroscopic, and computational methods. Overall, we discuss here that structural plasticity within the SF is a key molecular determinant of ion channel gating behavior.

Fast Li+ solid ion conductors are a key component of all-solid-state batteries, a technology currently under development. The possible use of metallic lithium as active material in solid-state batteries warrants a quantum step improvement of battery specific energy, enabling further electric vehicles application. Hereby, we report the synthesis and ion conduction properties of a new solid hybrid electrolyte based on the MIL-121 metal organic framework (MOF) structure. After an ion exchange procedure that introduces Li+ in the structure, a known quantity of a soaking electrolyte is incorporated. The soaking electrolyte is based on the EMIM-TFSI ionic liquid, thus we can classify our formulation as a MOF–ionic liquid hybrid solid electrolyte. Electrical conductivity is investigated by impedance spectroscopy and preliminary studies of ion dynamics are conducted by 7Li NMR. The field of MOF-based ion conductors remains in incipient stages of research. Our report paves the way towards the rational design of new solid-state ion conductors.

Operando characterization provides direct insight into material response under application conditions and it is essential to understand the stability limits of thermoelectric materials and their decomposition mechanisms. An operando setup capable of maintaining a thermal gradient while running DC current through a bar‐shaped sample has been developed. Under operating conditions, X‐ray scattering data can be measured along the sample to obtain spatially resolved structural knowledge in concert with measurement of electrical resistance and the Seebeck coefficient. Here thermoelectric β‐Zn4Sb3, which is a mixed ionic–electronic conductor, is studied, and a significant temperature dependence of the Zn migration is directly observed. Measurements with the thermal gradient applied either along or opposite to the DC current establish that the ion migration is an electrochemical effect rather than a thermodiffusion. Consideration of only the applied critical voltage or current density is insufficient for deducing the stability limits and structural integrity of materials with temperature‐dependent ion mobility. The present operando setup is not limited to studies of thermoelectric materials, and it also lends itself to studies of, for example, ion diffusion in solid‐state electrolytes or structural transformations in solid‐state reactions. [ABSTRACT FROM AUTHOR]

Molecular diffusion in nanoporous materials can be understood as series of dynamic hopping or exchange motions of molecules between different discrete sites. Exchange NMR offers the spectral resolution to distinguish between these different sites, based on isotropic and anisotropic NMR interactions that manifest differences in the local chemical or structural environments of molecules at different sites or their local orientations. Such interactions facilitate the observation of distinct adsorption environments and provide insights on the number and distributions of distinct types of environments and the geometries and motional correlation times of local hopping events between different sites. The temporal range accessible by exchange NMR is governed by the time required for the observation of the NMR signal (< 1 ms) and the return of the nuclear magnetic polarization to thermal equilibrium (typically several seconds). Over such timescales, this permits slow molecular exchange processes between local environments to be probed in great quantitative detail. The resulting insights on dynamic exchange or hopping of atoms, molecules, or ions in nanoporous solids provide a basis for understanding processes that occur over longer length and time scale, which ultimately account for their macroscopic diffusion properties. [ABSTRACT FROM AUTHOR]

Molecular crystals have attracted increasing attention as a candidate for innovative solid electrolytes with solid-state Mg-ion conductivity. In this work, we synthesized a novel Mg-ion-conducting molecular crystal, Mg{N(SO2CF3)2}2(CH3OC5H9)2 (Mg(TFSA)2(CPME)2), composed of Mg bis(trifluoromethanesulfonyl)amide (Mg(TFSA)2) and cyclopentyl methyl ether (CPME) and elucidated its crystal structure. We found that the obtained Mg(TFSA)2(CPME)2 exhibits solid-state ionic conductivity at room temperature and a high Mg-ion transference number of 0.74. Contrastingly, most Mg-conductive inorganic solid electrolytes require heating above 150–300°C to exhibit ionic conductivity. These results further prove the suitability of molecular crystals as candidates for Mg-ion-conducting solid electrolytes.

The dynamically active synaptic elements are the fundamental building blocks in neuromorphic systems towards artificial intelligence with computing and sensing capabilities. Here, a two-dimensional (2D) MoS2 synaptic transistor is fabricated by using poly(ethylene oxide) (PEO) and lithium perchlorate (LiClO4) as a laterally coupled ion-conducting electrolyte. Due to the strong electric double layer (EDL) effect, a low operating voltage of 1 V and a high current on/off ratio of 105 have been obtained. In addition, short-term and long-term plasticity of typical synaptic behaviors have been successfully simulated, such as excitatory postsynaptic current, paired pulse facilitation long-term potentiation, long-term depression, and dynamic filtering. These results can provide new opportunities and strategies in building hybrid and low-dimensional neuromorphic systems for future artificial intelligence applications. [ABSTRACT FROM AUTHOR]

Light‐emitting electrochemical cells (LECs) are devices that utilize efficient ion redistribution to produce high‐efficiency electroluminescence in a simple device architecture. Prototypical polymer LECs utilize three components in the active layer: a luminescent conducting polymer, a salt, and an electrolyte. Similarly, many small‐molecule LECs also utilize an electrolyte to disperse salts. In these systems, the electrolyte is incorporated to efficiently conduct ions and to maintain phase compatibility between all components. However, certain LEC approaches and materials systems enable device operation without a dedicated electrolyte. This review describes the general methods and materials used to circumvent the use of a dedicated electrolyte in LECs. The techniques of synthetically coupling electrolytes, incorporating ionic liquids, and introducing inorganic salts are presented in view of research efforts to date. The use of these techniques in emerging classes of light‐emitting electrochemical cells is also discussed. These approaches have yielded some of the most efficient, long‐lasting, and commercially applicable LECs to date. [ABSTRACT FROM AUTHOR]

A strategy based on covalent organic frameworks for ultrafast ion transport involves designing an ionic interface to mediate ion motion. Electrolyte chains were integrated onto the walls of one‐dimensional channels to construct ionic frameworks via pore surface engineering, so that the ionic interface can be systematically tuned at the desired composition and density. This strategy enables a quantitative correlation between interface and ion transport and unveils a full picture of managing ionic interface to achieve high‐rate ion transport. Moreover, the effect of interfaces was scaled on ion transport; ion mobility is increased in an exponential mode with the ionic interface. This strategy not only sets a benchmark system but also offers a general guidance for designing ionic interface that is key to systems for energy conversion and storage. [ABSTRACT FROM AUTHOR]