Pore Conductance Research Articles

Understanding the evolution of cold sensing and menthol activation in TRPM8.

Transient receptor potential melastatin 8 (TRPM8) is a polymodally gated ion channel activated by a variety of stimuli including menthol, cold, and pH. These chemical and physical stimuli ultimately regulate the ion conductance pore. While the menthol binding site and ion conduction pathway gate have been identified, the physics that underlies the mechanism of activation among different stimuli remains elusive. Particularly, the temperature modulation, how TRPM8 converts small changes in temperature into a conformational change, ultimately resulting in signal transduction is not well understood. Here to shed light into polymodal regulation of TRPM8, we perform a comparative analysis of conformational dynamics and functional characterizations of ancestral and extant human TRPM8. We use ancestral sequence reconstruction, a computational molecular evolution tool, to explore that ability to disentangle TRPM8 activation modes, which presumably emerged distinctly over evolutionary time. Based on the extant sequences of TRPM8, ancestral reconstruction was used to determine the DNA sequences of the last common primate, mammalian, and vertebrate ancestors. Resurrection and experimental analysis of these ancestral TRPM8 proteins show them to be functional in heterologous mammalian cells. Whole-cell patch-clamp electrophysiology and calcium mobilization assays confirm our hypothesis that the cold and menthol responses differ in terms of emergence and sensitivity between the ancestral constructs suggesting a new method to dissect polymodal protein behavior. Furthermore, comparative conformational analysis of ancestral and extant TRMP8 through the Dynamic Flexibility and Dynamic Coupling analysis also further support this hypothesis and provide dynamical finger prints for menthol and cold sensation.

Paracellular ion transport in claudin-15 ion channels.

Claudins, one of the primary constituents of tight junctions, assemble to form paracellular channels that regulate ion permeability. From the resolution of its crystallographic structure emerged the opportunities to investigate how structural properties of the pore determine function. In claudin-15, a cation-selective channel in the small intestine, the ion conduction pores are composed of the assembly of four β-sheets from extracellular domains of claudins between two membranes. We used computational methods to map the effect of mutation of the pore-facing residues on charge- and size-selectivity of claudin-15. Utilizing molecular dynamics simulations of a three-pore system in an infinitely long claudin strand, an electric field was applied to induce ion transport. Single pore ion conductance was calculated and the charge-selectivity of the pore was compared against experimental permeability of claudin-15. More than ten single-point and double-point mutations were identified that affect the charge (cation) selectivity of the pore. Coupled with structural variation of the pore, our results elucidate the structural basis for claudin-15 permselectivity.

Carbonaceous electrode materials for supercapacitor: Preparation and surface functionalization

Supercapacitors became more and more important recently in the area of energy storage and conversion. Their large power deliveries abilities, high stability and environmental friendliness characteristics draw tremendous attention in high-power applications such as public transit networks. Carbonaceous materials with unique surface and electrochemical properties were widely used in supercapacitors as electrode materials. This review focuses on the developments in supercapacitor electrodes made from carbonaceous materials recently, their working principle and evaluation parameters were summarized briefly. The preparation methods and electrochemical properties of different carbonaceous materials were compared and classified. It was found that the surface situation (e.g., porous structure, hydrophilic) of carbonaceous materials strongly affect the electrochemical performances of supercapacitor. So far, active carbons would be the most applicable carbonaceous electrode materials owing to their good chemical stability and conductivity, extensive accessibility inexpensiveness. But their energy densities still fall behind practical demands. Both theoretical calculations and experimental studies show that surface modification and doping of carbonaceous materials can not only optimize their pore size, structure, conductivity and surface properties, but also can introduce extra pseudocapacitance into these materials. Considering global environmental pollution and energy shortage problems nowadays, we sincerely suggested that future work should focus on domestic, medical and industrial wastes residues derived carbonaceous materials and scaled production process such as reactors and exhaust gas treatment.

Co-precipitation reaction: A facile strategy for designing hierarchical porous carbon nanosheets for EDLCs and zinc-ion hybrid supercapacitors

Hierarchical porous carbon is a valuable electrode material for electrochemical energy storage devices by virtue of its high specific surface area, excellent conductivity, and large pore volume. Herein, a simple, convenient and cheap self-made Fe-based template strategy is innovated to prepare hierarchical porous carbon employing coal chemical byproducts anthracene as carbon precursor, which is utilized as electrode materials of electrical double layer capacitors (EDLCs) and zinc ions hybrid supercapacitors (ZHSs). Benefiting from the high specific surface area (2085.1 m2 g−1), feasible micropore content (0.28 cm3 g−1), suitable oxygen content (11.57 at%) and two-dimensional nanosheet structure, the optimal sample delivered a high specific capacitance value of 183.5 F g−1 at 0.05 A/g and excellent rate capability (109.5 F g−1 at 20 A/g) for symmetric supercapacitor. Meanwhile, the as-fabricated ZHSs exhibited remarkable specific capacitance (181.67 mAh/g at 0.05 A/g), superior energy density (145.2 Wh kg−1), high power density (14.5 kW kg−1) and splendid cycling stability (∼91.25 % after 40,000 charge/discharge cycles at 2 A g−1). This work affords a new idea for the synthesis of template carbon using a feasible and low-cost co-precipitation reaction route and has great significance for the development of high-performance electrochemical energy storage device.

Patch Amperometry and Intracellular Patch Electrochemistry.

Both patch amperometry (PA) and intracellular patch electrochemistry (IPE) take advantage of a recording configuration where an electrochemical detector-carbon fiber electrode (CFE)-is housed inside a patch pipette. PA, which is employed in cell-attached or excised inside-out patch clamp configuration, offers high-resolution patch capacitance measurements with simultaneous amperometric detection of catecholamines released during exocytosis. The method provides precise information on single-vesicle size and quantal content, fusion pore conductance, and permeability of the pore for catecholamines. IPE, on the other hand, measures cytosolic catecholamines that diffuse into the patch pipette following membrane rupture to achieve the whole-cell configuration. In amperometric mode, IPE detects total catechols, whereas in cyclic voltammetric mode, it provides more specific information on the nature of the detected molecules and may selectively quantify catecholamines, providing a direct approach to determine cytosolic concentrations of catecholaminergic transmitters and their metabolites. Here, we provide detailed instructions on setting up PA and IPE, performing experiments and analyzing the data.

Multistage Activation of Anthracite Coal-Based Activated Carbon for High-Performance Supercapacitor Applications

An anthracitic coal-derived activated porous carbon is proposed as a promising carbon electrode material for supercapacitor (SC) applications. The specific capacitance of this activated carbon SC electrode is related to the characteristics, such as specific surface area, pore size distribution, wettability, and conductivity. In the present work, a series of anthracite-based activated carbons (ABAC) were prepared via a multistage activation process and used as electrode materials for SCs. The multistage activation experiment was developed by exploring different activation temperatures, precursor/activating agent mass ratios, and process treating environments. The electrochemical performance of ABACs was evaluated in a three-electrode testing system. Multiple electrolytes were utilized, such as 1 M sulfuric acid (H2SO4) and 1 and 6 M potassium hydroxide (KOH) solutions. An optimum ABAC electrode was obtained, characterized by its largest wettability and superior conductivity, and achieved excellent electrochemical performance. The three-electrode system exhibited a specific capacitance of 288.52 and 260.30 F/g at 0.5 A/g in the 1 M H2SO4 and 6 M KOH electrolytes, respectively. It was found that moderate multistage activation temperatures are beneficial for the electrolyte uptake which enhances the specific capacitance. The high content of the oxygen functional groups on the activated carbon surface greatly improved its specific capacitance due to the increase in wettability. In the 1 M H2SO4 electrolyte, the working electrode exhibited better performance than in 1 M KOH because the ion diameter in the acidic electrolyte was more suitable for pore diffusion. The concentrated KOH electrolyte leads to an increase in specific capacitance due to increased ions being adsorbed by a certain number of the hydrophilic pores. Moreover, the specific capacitance of the optimum ABAC sample remained at 95.4% of the initial value after 1000 galvanostatic charge–discharge tests at 0.5 A/g, which is superior to the performance of SC grade commercial carbon.

Fine Pore‐Structure Engineering by Ligand Conformational Control of Naphthalene Diimide‐Based Semiconducting Porous Coordination Polymers for Efficient Chemiresistive Gas Sensing

AbstractExploring new porous coordination polymers (PCPs) that have tunable structure and conductivity is attractive but remains challenging. Herein, fine pore structure engineering by ligand conformation control of naphthalene diimide (NDI)‐based semiconducting PCPs with π stacking‐dependent conductivity tunability is achieved. The π stacking distances and ligand conformation in these isoreticular PCPs were modulated by employing metal centers with different coordination geometries. As a result, three conjugated PCPs (Co−pyNDI, Ni−pyNDI, and Zn−pyNDI) with varying pore structure and conductivity were obtained. Their crystal structures were determined by three‐dimensional electron diffraction. The through‐space charge transfer and tunable pore structure in these PCPs result in modulated selectivity and sensitivity in gas sensing. Zn−pyNDI can serve as a room‐temperature operable chemiresistive sensor selective to acetone.

Fine Pore-Structure Engineering by Ligand Conformational Control of Naphthalene Diimide-Based Semiconducting Porous Coordination Polymers for Efficient Chemiresistive Gas Sensing.

Exploring new porous coordination polymers (PCPs) that have tunable structure and conductivity is attractive but remains challenging. Herein, fine pore structure engineering by ligand conformation control of naphthalene diimide (NDI)-based semiconducting PCPs with π stacking-dependent conductivity tunability is achieved. The π stacking distances and ligand conformation in these isoreticular PCPs were modulated by employing metal centers with different coordination geometries. As a result, three conjugated PCPs (Co-pyNDI, Ni-pyNDI, and Zn-pyNDI) with varying pore structure and conductivity were obtained. Their crystal structures were determined by three-dimensional electron diffraction. The through-space charge transfer and tunable pore structure in these PCPs result in modulated selectivity and sensitivity in gas sensing. Zn-pyNDI can serve as a room-temperature operable chemiresistive sensor selective to acetone.

Effect of Cobalt Ferrite Nanoparticles in a Hydrophilic Shell on the Conductance of Bilayer Lipid Membrane.

We measured the conductance of bilayer lipid membranes of diphytanoylphosphatidylcholine induced by interaction with cubic magnetic nanoparticles (MNPs) of cobalt ferrite 12 and 27 nm in size and coated with a hydrophilic shell. The MNP coating is human serum albumin (HSA) or polyethylene glycol (PEG). The interaction of nanoparticles added to the bulk solution with the lipid bilayer causes the formation of metastable conductive pores, which, in turn, increases the integral conductance of the membranes. The increase in conductance with increasing MNP concentration was practically independent of the particle size. The dependence of the bilayer conductance on the concentration of PEG-coated MNPs was much weaker than that on the concentration with a shell of HSA. Analyzing the current traces, we believe that the conductive pores formed as a result of the interaction of nanoparticles with the membrane can change their size, remaining metastable. The form of multilevel current traces allows us to assume that there are several metastable pore states close in energy. The average radius of the putative cylindrical pores is in the range of 0.4-1.3 nm.

Graphene-Based Metal-Organic Framework Hybrids for Applications in Catalysis, Environmental, and Energy Technologies.

Current energy and environmental challenges demand the development and design of multifunctional porous materials with tunable properties for catalysis, water purification, and energy conversion and storage. Because of their amenability to de novo reticular chemistry, metal-organic frameworks (MOFs) have become key materials in this area. However, their usefulness is often limited by low chemical stability, conductivity and inappropriate pore sizes. Conductive two-dimensional (2D) materials with robust structural skeletons and/or functionalized surfaces can form stabilizing interactions with MOF components, enabling the fabrication of MOF nanocomposites with tunable pore characteristics. Graphene and its functional derivatives are the largest class of 2D materials and possess remarkable compositional versatility, structural diversity, and controllable surface chemistry. Here, we critically review current knowledge concerning the growth, structure, and properties of graphene derivatives, MOFs, and their graphene@MOF composites as well as the associated structure-property-performance relationships. Synthetic strategies for preparing graphene@MOF composites and tuning their properties are also comprehensively reviewed together with their applications in gas storage/separation, water purification, catalysis (organo-, electro-, and photocatalysis), and electrochemical energy storage and conversion. Current challenges in the development of graphene@MOF hybrids and their practical applications are addressed, revealing areas for future investigation. We hope that this review will inspire further exploration of new graphene@MOF hybrids for energy, electronic, biomedical, and photocatalysis applications as well as studies on previously unreported properties of known hybrids to reveal potential "diamonds in the rough".

Novel synthesis of N-doped graphene quantum dot as conductive agent for carbon based supercapacitors

Conductive agent can increase conductivity and construct pore structure in supercapacitor (SC) electrode as clean renewable energy. Carbon black (CB) is common conductive agent but its zero dimension hinders efficient charge-transfer conductive bridge. Combining CB with other carbon materials can possibly solve this issue. Graphene quantum dot (GQD) with high hydrophilicity and stable doping features is easier and cheaper to develop. Previous synthesis of GQD requires complex process and lacks large-scale production. In this study, novel one-step thermal treatment was provided to synthesize N-doped GQD. Citric acid and urea ratios were varied to synthesize N-doped GQD with different N-doping extents and electrical conductivities. CB and GQD mixtures, GQD and CB are used as conductive agent for fabricating SC electrodes. Activated carbon electrode with CB and GQD mixture shows the highest specific capacitance (CF) of 241.4 F/g at 20 mV/s, while electrodes without conductive agent and with CB conductive agent respectively shows CF of 41.5 and 108.6 F/g, due to more functional groups, defects, hydrophilic sites and electrochemical surface area of the former case. Symmetric SC with CB and GQD shows a maximum energy density of 10.54 Wh/kg at 550 W/kg, and CF retention of 85% and Coulombic efficiency of 80% after 5000 charging/discharging cycles.

S‐Doped Porous Carbon Cage with Good Accommodation Ability as an Effective S Host for Li‐S Batteries

AbstractThe practical application of Li−S batteries is still limited by the fundamental problems of the insulation properties of sublimed S and the “shuttle effect” of polysulfides. S‐doped porous carbon cage (SPCC) obtained by the catalytic guidance methodology is employed as a highly efficient S host material for Li−S batteries, which presents the cage‐like morphology coupled with abundant pore channels. Compared to the undoped PCC, SPCC exhibits higher electrical conductivity. The composite of sublimed S and SPCC (S@SPCC) employed as cathode for Li−S batteries possesses a higher reversible capacity, superior rate capability and better durability in comparison with that of S@PCC cathode. The synergistic effect of robust matrix associated with good electrical conductivity and abundant pore channels of SPCC is beneficial for the fast electron transport and shorten the Li‐ion diffusion distance. Besides, S doping possesses the positive function to attract Li‐polysulfides, inhibiting the shuttle of Li‐polysulfides and contributing to the superior electrode behavior of the S@SPCC cathode.

Camphene-Assisted Fabrication of Free-Standing Lithium-Ion Battery Electrode Composites

Free-standing electrode (FSE) architectures hold the potential to dramatically increase the gravimetric and volumetric energy density of LIBs by eliminating the parasitic dead weight and volume associated with traditional metal foil current collectors, however current FSE fabrication methods suffer from insufficient mechanical stability, electrochemical performance, or industrial adoptability. Here, we demonstrate a scalable camphene-assisted fabrication method that allows simultaneous casting and templating of FSEs comprised of common LIB materials with performance superior to foil-cast counterparts. These porous, lightweight, and robust electrodes simultaneously enable enhanced rate performance by improving mass and ion transport within the percolating conductive carbon pore network and eliminating current collectors for efficient and stable Li+ storage (> 1000 cycle in half-cells) at increased gravimetric and areal energy densities. Compared to conventional foil-cast counterparts, the camphene-derived electrodes exhibit ~1.5x enhanced gravimetric energy density, increased rate capability, and improved capacity retention in coin-cell configurations. A full cell with free-standing anode and cathode cycled for over 250 cycles with greater than 80% capacity retention at an areal capacity of 0.73 mAh/cm2. This active-material-agnostic electrode fabrication method holds potential to tailor the morphology of flexible, current-collector-free electrodes to optimize LIBs for high power or high energy density Li+ storage and is applicable to other electrochemical technologies and advanced manufacturing methods.

Mechanisms controlling the hydraulic conductivity of anionic polymer-enhanced GCLs

The hydraulic conductivity (k) of specimens of enhanced-bentonite geosynthetic clay liners (EB-GCLs) comprising anionic polymers permeated with two concentrated salt solutions, 500 mM NaCl and 167 mM CaCl2, was measured to determine the effects of polymer properties and specimen preparation method on the k and the associated roles of polymer retention and elution in dictating the measured k. The results of hydrogel formation tests illustrated that poly(acrylic acid) hydrogel was formed in solutions tested during EB-GCL hydration. A dry sprinkling method of specimen preparation resulted in low k (≤5.5 × 10−11 m/s) in multiple EB-GCLs, with a low fraction (≤2.5%) of retained polymer. In contrast, polymer elution from EB-GCLs prepared using a dry mixing method resulted in interaggregate seepage and an increase in k. Higher polymer retention occurred for the wet-mixed EB-GCLs, but did not directly correlate to low k. The long-term k of the EB-GCLs is dependent on several factors, including (i) formation of hydrogel, (ii) mobilization of hydrogel into and blocking of the most conductive pores, (iii) balance of seepage forces and hydrogel crosslink bond strength, (iv) kinetics of hydrogel formation, and (v) adsorption of polymer to the surfaces of the bentonite particles or aggregates of particles.

Camphene-Assisted Fabrication of Free-Standing Lithium-Ion Battery Electrode Composites.

Free-standing electrode (FSE) architectures hold the potential to dramatically increase the gravimetric and volumetric energy density of lithium-ion batteries (LIBs) by eliminating the parasitic dead weight and volume associated with traditional metal foil current collectors. However, current FSE fabrication methods suffer from insufficient mechanical stability, electrochemical performance, or industrial adoptability. Here, we demonstrate a scalable camphene-assisted fabrication method that allows simultaneous casting and templating of FSEs comprising common LIB materials with a performance superior to their foil-cast counterparts. These porous, lightweight, and robust electrodes simultaneously enable enhanced rate performance by improving the mass and ion transport within the percolating conductive carbon pore network and eliminating current collectors for efficient and stable Li+ storage (>1000 cycles in half-cells) at increased gravimetric and areal energy densities. Compared to conventional foil-cast counterparts, the camphene-derived electrodes exhibit ∼1.5× enhanced gravimetric energy density, increased rate capability, and improved capacity retention in coin-cell configurations. A full cell containing both a free-standing anode and cathode was cycled for over 250 cycles with greater than 80% capacity retention at an areal capacity of 0.73 mA h/cm2. This active-material-agnostic electrode fabrication method holds potential to tailor the morphology of flexible, current-collector-free electrodes, thus enabling LIBs to be optimized for high power or high energy density Li+ storage. Furthermore, this platform provides an electrode fabrication method that is applicable to other electrochemical technologies and advanced manufacturing methods.

Achieving High‐Performance Oxygen Reduction Catalyst and Zn–Air Battery through a Synergistic Nitrogen Doping Strategy

It remains a challenge to achieve high‐performance, low‐cost, and robustly durable Fe, N co‐doped carbon‐based oxygen reduction reaction (ORR) catalysts with abundantly accessible Fe–NX sites. Herein, a novel scheme is designed to enrich the pore structure, increase the specific surface area, and generate spatially isolated Fe–NX sites of the ORR catalyst, in which pyridine nitrogen‐rich lamellar metal–organic complex (Fe–tetrapyridophenazine) is employed as the precursor and 2D graphitic carbon nitride (g‐C3N4) as additional nitrogen source for achieving synergistic nitrogen‐doping effect. The introduction of g‐C3N4 not only ameliorates the nitrogen coordination environment of metal active centers of the composite, but also increases the specific surface area and improves the pore structure. The resultant Fe–NC&CN composite has abundant active sites as well as remarkable electrical conductivity and suitable pore size for electron transfer and reactant diffusion. As expected, the catalyst exhibits excellent ORR activity, driving the reaction with low overpotential (E1/2 = 0.879 V) and remaining stable over a long reaction time (93% for 60 000 s), better than commercial Pt/C (20%) in all aspects. The assembled Zn–air battery exhibits high open‐circuit voltage of 1.566 V and high specific capacity of 815 mAh gZn−1, as well as stable and persistent discharge performance.

Tumor–neuron interactions: A novel concept contributor to glioblastoma invasion

Tumor–neuron interactions: A novel concept contributor to glioblastoma invasion

Heterosynaptic plasticity in biomembrane memristors controlled by pH

In biology, heterosynaptic plasticity maintains homeostasis in synaptic inputs during associative learning and memory, and initiates long-term changes in synaptic strengths that nonspecifically modulate different synapse types. In bioinspired neuromorphic circuits, heterosynaptic plasticity may be used to extend the functionality of two-terminal, biomimetic memristors. In this article, we explore how changes in the pH of droplet interface bilayer aqueous solutions modulate the memristive responses of a lipid bilayer membrane in the pH range 4.97–7.40. Surprisingly, we did not find conclusive evidence for pH-dependent shifts in the voltage thresholds (V*) needed for alamethicin ion channel formation in the membrane. However, we did observe a clear modulation in the dynamics of pore formation with pH in time-dependent, pulsed voltage experiments. Moreover, at the same voltage, lowering the pH resulted in higher steady-state currents because of increased numbers of conductive peptide ion channels in the membrane. This was due to increased partitioning of alamethicin monomers into the membrane at pH 4.97, which is below the pKa (~5.3–5.7) of carboxylate groups on the glutamate residues of the peptide, making the monomers more hydrophobic. Neutralization of the negative charges on these residues, under acidic conditions, increased the concentration of peptide monomers in the membrane, shifting the equilibrium concentrations of peptide aggregate assemblies in the membrane to favor greater numbers of larger, increasingly more conductive pores. It also increased the relaxation time constants for pore formation and decay, and enhanced short-term facilitation and depression of the switching characteristics of the device. Modulating these thresholds globally and independently of alamethicin concentration and applied voltage will enable the assembly of neuromorphic computational circuitry with enhanced functionality.Impact statementWe describe how to use pH as a modulatory “interneuron” that changes the voltage-dependent memristance of alamethicin ion channels in lipid bilayers by changing the structure and dynamical properties of the bilayer. Having the ability to independently control the threshold levels for pore conduction from voltage or ion channel concentration enables additional levels of programmability in a neuromorphic system. In this article, we note that barriers to conduction from membrane-bound ion channels can be lowered by reducing solution pH, resulting in higher currents, and enhanced short-term learning behavior in the form of paired-pulse facilitation. Tuning threshold values with environmental variables, such as pH, provide additional training and learning algorithms that can be used to elicit complex functionality within spiking neural networks.Graphical abstract

Experimental and Numerical Studies of the Effect of Microstructure of Ionic Conductors on Generation of Hydrogen in Solid Oxide Electrochemical Cells (SOC)

Ceramic ionic conductors are applied in innovative systems for highly efficient and clean power generation. The oxygen separation membranes and solid oxide fuel cells (SOFC) and solid oxide electrolyzers (SOE) can be the examples.Influence of various structural properties of ceramic ionic conductors which are used for solid oxide fuel cells was well-defined and described using several mathematical models. Such parameters as ionic and electronic conductivity, porosity, tortuosity, shape and distribution of pores were included. In case of solid oxide electrolysis cells, effects of these parameters on the electrolysis reaction remain unclear and obscure. There is no clearly defined correlation, neither there is an optimization tool for modification of the parameters to maximize the performance of solid oxide cell operating in regenerative mode. For that reason it is necessary to perform a complete comprehensive analysis combining both the experimental and numerical techniques to identify the key microstructural parameters and their correlation with the performance of electrochemical reaction. The work was aimed at verification of data presented in earlier studies which advised that porosity of electrodes of SOEs needs to be different than in the case of SOFCs, however different values were claimed. Mingyi et al. [1] indicated that optimum porosity for SOEC is about 45%, however several other studies advised on different values.This paper presents results of numerical simulations and correlation of material properties with operational characteristic of a solid oxide electrochemical cell which were followed by initial experimental investigations towards validation of the numerical model, including the analysis of selected operational states. Model was established on the basis of theoretical correlations between microstructural parameters and macro-level performance. It was used for performing variant analysis of different modes of operation under varied conditions. The outcomes of the numerical investigations made it possible to define the requirements for fabrication of modified cells for high temperature electrolysis which were studied.The work presents preliminary results of electrochemical characterization of modified cells and an attempt to generalize the model of SOC customized to highly efficient electrolysis.The general concept of optimizing the performance of SOE by fine-tuning of the microstructure which was proposed earlier [2] is assessed throughout experiments using in-house 50 mm x 50 mm cells fabricated in the Institute of Power Engineering. The proposed path for tailoring the microstructural properties is presented and discussed.

Modeling of Porous Lithium Metal Electrodes: Turning the Li-Dendrite Problem Around

The properties of rechargeable lithium-ion batteries are determined by the electrochemical and kinetic properties of their constituent materials as well as by their underlying microstructure. Microstructural design can be leveraged to achieve a leap in performance and durability. Here we investigate a porous electrode structure, as a strategy to increase the surface area, and provide structural stability for Li-metal anodes. The porous architecture consists of a mixed electron/ion conductor that function as a scaffold for lithium metal deposition. A new finite element model was developed to simulate the large topological changes associated with Li plating/stripping. This model is used to predict the current density distribution as a function of material and structural properties. A dimensionless quantity that combines Li-ion conductivity, surface impedance and average pore size is shown to be a good indicator to predict the peak current density. Preventing current localization at the separator reduces the risk of cell shorting. The analyses show that the peak current scales as (hG)1/2, where h is the ratio between surface and bulk conductivity and G is the average pore size. Stability analyses suggest that the growth is morphologically stable, and that confining Li-plating into pores can enable high-energy density solid-state batteries.