Transference Number Research Articles

Biomimetic Channels Design in Metal-Organic Framework Enabling Highly Lithium-Ion Conduction for Lithium-Metal Batteries.

Solid-state electrolytes (SSEs) based on metal-organic frameworks (MOFs) are an ideal material for constructing high-performance lithium metal batteries (LMBs). However, the low ion conductivity and poor interface contact (especially at low temperatures) still seriously hinder its further application. Herein, inspired by the Na+/K+ conduction in biology systems, a series (NH2, OH, NH-(CH2)3-SO3H)-modified MIL-53-X as SSEs is reported. These functional groups are similar to anions suspended in biological ion channels, partially repelling anions while allowing cations to be effectively transported through pore channels. Subsequently, MIL-53-X with hierarchical pore structure (H-MIL-53-X) is obtained by introducing lauric acid as a regulator, and then the effects of structural design and morphology control on its performance are explored. The conductivity of H-MIL-53-NH-SO3Li with multi-level pore structure and modified by sulfonic acid groups reached 2.2×10-3Scm-1 at 25°C, lithium-ion transference number of 0.78. Besides, the H-MIL-53-NH-SO3Li still has an excellent conductivity of 10-4Scm-1 at -40°C. Additionally, LiFePO4/Li batteries equipped with H-MIL-53-NH-SO3Li SSEs could operate stably for over 200 cycles at 0.1C. The strategy of combining structural and morphological design of MOFs with biomimetic ion channels opens new avenues for the design of high-performance SSEs.

Diethylenetriaminepentaacetic Acid-based Conducting Solid Polymer Electrolytes Impede Lithium Dendrites and Impart Antioxidant Capacity in Lithium-Ion Batteries.

In the development of lithium-ion batteries (LIBs), cheaper and safer solid polymer electrolytes are expected to replace combustible organic liquid electrolytes to meet the larger market demand. However, low ionic conductivity and inadequate cycling stability impede their commercial viability. Herein, a novel flexible conducting solid polymer electrolytes (CSPEs) based on polyvinyl alcohol (PVA) and ion-polarized diethylenetriaminepentaacetic acid (P-DETP) is developed for the first time and applied in LIBs. PVA and P-DETP form a compact polymer network through hydrogen bonding, enhancing the thermomechanical stability of CSPE while restricting the migration of larger anions. Furthermore, density functional theory calculations confirm that P-DETP can facilitate the dissociation of Li+-TFSI- via electrostatic attraction, resulting in increased mobility of lithium ions. Additionally, P-DETP contributes to the formation of a stable electrode-electrolyte interface layer, effectively suppressing the growth of lithium dendrites and improving antioxidant capacity. These synergistic effects enable CSPE to exhibit remarkable properties including high ionic conductivity (2.8 × 10-4 S cm-1), elevated electrochemical potential (5.1V), and excellent lithium transference number (0.869). Notably, the P-DETP/LiTFSI CSPE demonstrates stable performance not only in LiFePO4 batteries but also adapts to high-nickel ternary LiNi0.88Co0.06Mn0.06O2 cathode, highlighting its immense potential for application in high energy density LIBs.

An oxygen-defective framework with intensified Lewis acidity reinforcing composite electrolyte for all-solid-state lithium metal batteries

Composite solid electrolytes (CSEs) are considered a key component of all-solid-state lithium metal batteries, regarded as the next generation of energy storage devices with high energy density and long operating life. Numerous studies have shown that the performance of CSEs is closely related to the structure of the fillers and the interactions between fillers and other components, including polymer matrices and lithium salts. To create more abundant interaction sites in CSEs, we designed a nanostructured framework with intensified Lewis acidity (PVDF-HFP/Ov-CeO2) for poly(ethylene) oxide (PEO) electrolyte (denoted as Ov-CeO2-CSE). The mystery concerning the nanostructured framework adsorbs with PEO polymer and dissociates TFSI− and its influence on the electrochemical lithium ions storage performance is meticulously revealed by coupling experimental with theoretical results. Impressively, the prepared Ov-CeO2-CSE shows improved ionic conductivity (1.76 × 10−4 S cm−1 at 30 °C) and a good lithium-ion transference number (0.49). The Li||Ov-CeO2-CSE||Li cell exhibits great cyclability over 3,500 h at a current density of 0.1 mA cm−2 (areal capacity: 0.1 mAh cm−2, 60 °C). Furthermore, the Li||Ov-CeO2-CSE||LFP cell delivers a high specific capacity of 154.6 mAh g−1 at a current density of 0.5 C, stably maintained over 500 cycles. This work provides a potential strategy for designing multifunctional frameworks by efficient interfaces to build advanced all-solid-state lithium metal batteries.

A modified separator based on ternary mixed-oxide for stable lithium metal batteries

Li metal batteries (LMBs) are among the most promising options for next-generation secondary batteries under the rapidly growing demand for high-energy–density electrochemical energy storage. However, the implementation of LMBs are hindered by major obstacles such as dentritic Li deposition and low cycling Coulombic efficiency. A practical functional separator is developed in this study, which consists of a Lewis acidic mixed oxide of ZrO2-SiO2-Al2O3 as a functional coating with anion anchoring ability to modulate ion transport in the vicinity of the Li metal anode, delivering a high Li+ transference number of 0.88 in carbonate electrolytes that suppresses dendrite formation. The strong Lewis acid sites in ZrO2-SiO2-Al2O3 originate from coordinatively unsaturated Zr4+ ions, which immobilize anions and reduce their decomposition rate. This significantly improves the chemical stability of the electrolyte and induces a more stable solid electrolyte interphase layer. The modified separator enables an anode-free cell containing a high-loading LiNi0.8Co0.1Mn0.1O2 cathode to present stable charge and discharge cycling for 150 cycles at 0.5C. By effectively suppressing Li dendrite growth and supporting the long-term operation of anode-free LMBs, this study offers a novel approach to rationally design mixed oxides with high Lewis acidity for functional separators.

Ion transport properties and performance of gellan gum based composite polymer membrane electrolytes in proton battery and PEMFC applications

Biopolymer Gellan gum (GG) incorporated with ammonium iodide (NH₄I) salts and inorganic filler nano-TiO2 improved the ion transport facility in the salt-polymer matrix. The crystalline/amorphous nature of the membranes and the presence of n-TiO2 are evident from XRD analysis. The vibration modes corresponding to the characteristic functional groups and bonding interactions within the polymer matrix and incorporated filler materials present in the as-prepared membranes were analyzed using FTIR technique respectively. The ion transport parameters such as ionic conductivity (σ), diffusion coefficient (D), and mobility (μ), were studied using Ac impedance, transference number measurement, and FTIR deconvolution. The biopolymer membrane with the composition, 1 g GG: 0.3 M.wt% of NH4I (GGAI-3) shows the highest ionic conductivity of 2.65 ± 0.03×10−3 S/cm and on addition of 0.1 M.wt% of n-TiO2 (GGAIT-1) the increase in ionic conductivity of 4.07 ± 0.02×10−2 S/cm was observed. The H¹NMR studies help in understanding the mobility of charge carriers upon their chemical shifts. The glass transition temperature values of the as-prepared membranes were determined using DSC studies. The morphological change on the surface of the GG polymer membrane due to the addition of NH4I and n-TiO2 were analyzed using the SEM technique. The thermal, mechanical, and chemical stability of the highest ion-conducting biopolymer and composite polymer membranes were assessed using TGA, mechanical stability tests, and chemical stability tests. The IEC test exhibits the number of exchangeable ions in the polymer matrix. Utilizing the GGAI-3 and GGAIT-1 membranes as electrolytes, proton batteries were constructed and observed to have the pseudocapacitive behaviour; as the electrodes experience surface limited redox reaction at the electrode-electrolyte interface. The PEMFC cell using the GGAI- 3 and GGAIT-1 as proton exchange membrane exhibits the OCV of 646 mV and 682 mV respectively. Their performances were analyzed using the I-V polarization curve resulted with the power density of 0.14 mW/cm2and 0.34 mW/cm2 respectively.

A Clay-Based Quasi-Solid-State electrolyte with high cation selective channels for High-Performance aqueous Zinc-Ion batteries

A clay-based quasi-solid-state electrolyte was prepared using dimethyl sulfoxide (DMSO) intercalated kaolinite as the raw material to suppress the adverse effects of free water molecules on aqueous zinc-ion batteries (AZIBs). Based on the inherent water absorption and retention properties of clay kaolinite, as well as the interlayer modification, this clay-based quasi-solid-state electrolyte not only achieved a low water content but also exhibited a strong water binding effect, which restricted the HER and side reactions involving water participation. Furthermore, the intercalation of DMSO increased the number of negative charges on the surface of kaolinite, resulting in the formation of a continuous spatial electrostatic field area around the kaolinite particles, which played a role in cation selectivity. The ionic transference number of the quasi-solid-state electrolyte reached 0.91. Additionally, the intercalation of DMSO broadened the interlayer ionic transport channels of kaolinite, further enhancing the transport efficiency of Zn2+ in the quasi-solid-state electrolyte, achieving uniform deposition of Zn2+ on the surface of the Zn anode, and suppressing dendrite growth to maintain a stable quasi-solid-state electrolyte/Zn anode interface. Zn||MnO2 battery assembled with this electrolyte demonstrated a discharge specific capacity of 301 mAh/g at a current density of 60 mA g−1. The Zn||MnO2 battery could be stably cycled for 1000 cycles at a current density of 150 mA g−1, and after 1000 cycles, the battery still maintained a discharge specific capacity of 248.2 mAh/g with a capacity retention rate of 84.8 %, showing excellent capacity performance and cycle stability. The Zn||MnO2 pouch battery could still provide stable power under heavy pressure, bending, and continuous tapping and had the potential for use in flexible batteries.

A COMPARATIVE STUDY OF HEADWAY-BASED AND TRANSPORT SYSTEM-BASED ASSIGNMENTS OF PUBLIC TRANSPORT IN VISUM: THE CITY OF KRYVYI RIH CASE

Many researchers have explored public transport assignment methodologies employing transport modelling software. Nevertheless, there remains a gap in evaluating real-world public transit networks utilizing diverse assignment procedures within Visum software. This paper introduces a thorough comparison of algorithms involved in public transport assignment processes, using the transport model of the city of Kryvyi Rih in Ukraine. The three scenarios of the model were developed depending on the public transport assignment procedure: headway-based, transport system-based utilized to all links, turns, and major turns in the network graph, and transport system-based applied only to the links, turns, and major turns traversed by the active public transport lines. The model of the network comprises 13 transport systems, 7 transport modes, 27598 links, 10097 nodes, 83270 turns, 238 zones, 1748 connections for private transport, 3013 connections for public transport, 534 stops, 1165 stop areas, 1190 stop points, 130 lines and 218 line routes. The transport demand model encompassed 14 demand segments. Compared to the outputs of the model calculation using the headway-based procedure, in the scenarios with transport system-based assignment, passenger flows on rail tram lines significantly decreased. Also, the results of scenarios with transport system-based assignment showed that the passengers extremely use parallel streets for travel from an origin to a destination. The modelling outputs for an actual urban network illustrate that the choice of the shortest route in the transport system-based assignment is closely linked to the main urban roads. This circumstance could potentially result in a rise in the number of transfers needed to sustain accessibility to districts residing far from the central highway.

Isocyanurate‐Derivative Enables Highly Compatible Poly‐Dioxane Electrolyte for Dendrite‐Free Li Metal Batteries

AbstractThe Li+ transport kinetics and electrochemical stability of advanced solid‐state Li metal batteries (SLMBs) are seriously limited by the actual electrolyte compositions. Here, a novel polyether‐based electrolyte (PTGDOX) is presented through in situ co‐polymerization by integrating 1,3‐dioxane with a multifunctional 1,3,5‐triglycidyl isocyanurate additive. The isocyanurate group in PTGDOX not only provides abundant coordinating sites for Li+ transfer and restricts the movement of anions, but also prompts a beneficial inorganic‐rich solid electrolyte interface on the Li electrode. As a result, PTGDOX exhibits a remarkably increased ionic conductivity of 0.48 mS cm−1 at 30 °C and a reasonable Li‐ion transference number of 0.68, enabling the Li||Li symmetric cells to stably cycle for over 2000 h at 1 mAh cm−2. Meanwhile, the assembled Li||LiFePO4 exhibit a 97.4% capacity retention after 700 cycles at 3 C with excellent thermal stability. Moreover, PTGDOX also demonstrates excellent interfacial compatibility with high‐voltage LiNi0.8Co0.1Mn0.1O2 cathode. As such, this work provides a facile and accessible strategy for designing interface‐stable polymer electrolytes and achieving practical dendrite‐free SLMBs.

The Self‐Expanding Frame of Graphydiyne Induces Rapid Transport of Lithium Ions in All‐Solid‐State Lithium Metal Batteries

AbstractLow ionic conductivity hinders the practical application of solid polymer electrolytes. Here, an interface‐oscillating polymer electrolyte (IOPE) based on graphdiyne (GDY) is designed and prepared to enable high‐performance all‐solid‐state lithium (Li) metal batteries (ASSLMBs). The affinity of GDY to Li ions induces the competitive adsorption of Li ions, weakens the coordination ability of Li ions with electron‐rich oxygen (on ethylene oxide), and accelerates the Li‐ion migration kinetics. The weak coordination between Li+‐acetylene greatly promotes the rapid reversible transition of GDY itself, resulting in strong self‐expanding/shrinking of the GDY skeleton and the GDY/polymer interface oscillation, and the reduction of the Li‐ion diffusion energy barrier at the interfaces. Consequently, the as‐prepared IOPE shows significantly improved Li‐ion conductivity (1.5 × 10−4 S cm−1 at 35 °C) and transference number, as well as excellent stability toward Li metal anodes. The ASSLMBs assembled with LiFePO4 cathodes and IOPE exhibit excellent rate and cycling performance, capable of stable operation for more than 250 cycles with a high‐capacity retention of 98% at 0.1C (1C = 170 mA g−1). The high‐performance all‐solid‐state Li metal pouch cells are also demonstrated to show great potential for the practical application of IOPE.

Phase transition and ionic conductivity of pyrrolidinium-based ionic plastic crystals with magnesium salts

Abstract Despite being safe for use in secondary Mg batteries, solid electrolytes exhibit lower ionic conductivities than those of traditional liquid electrolytes. Organic ionic plastic crystals—soft crystals with excellent thermal and electrochemical stabilities and ionic conductivities—are promising solid electrolytes. Herein, we investigated the effects of various anion species and Mg salt concentrations on the properties of pyrrolidinium-based organic ionic plastic crystals (N,N-diethylpyrrolidinium bis(fluorosulfonyl)amide [[C2epyr][FSA]] and N,N-diethylpyrrolidinium bis(trifluoromethylsulfonyl)amide [[C2epyr][TFSA]]) upon Mg(TFSA)2 addition. The Mg-ion transference number (tMg2+) was measured using the Vincent–Bruce method; ionic conductivity via impedance measurements; and phase transition via differential scanning calorimetry. The phase transition behavior, dissociation state of the Mg salt, and electrochemical properties varied with the organic ionic plastic crystal anionic structure. The FSA system became liquid when the Mg salt concentration exceeded 15 mol%. The ionic conductivity of the pyrrolidinium-based organic ionic plastic crystals increased substantially with the Mg salt concentration. In the solid state, [C2epyr][FSA]/Mg(TFSA)2 (5 mol%) (FT5) showed the highest ionic conductivity (2.9 × 10−4 S cm−1 at 25 °C). The tMg2+ of FT5 at 60 °C was 0.29. Mg exhibited redox behavior in FT5 but not in [C2epyr][TFSA]/Mg(TFSA)2 (5 mol%). The FSA− structure is suitable for Mg electrochemistry and will aid in developing high-performance secondary Mg batteries.

Designing a Refined Multi-Structural Polymer Electrolyte Framework for Highly Stable Lithium-Metal Batteries.

Rational structural designs of solid polymer electrolytes featuring rich interface-phase morphologies can improve electrolyte connection and rapid ion transport. However, these rigid interfacial structures commonly result in diminished or entirely inert ionic conductivity within their bulk phase, compromising overall electrolyte performance. Herein, a multi-component ion-conductive electrolyte was successfully designed based on a refined multi-structural polymer electrolyte (RMSPE) framework with uniform Li+ solvation chemistry and rapid Li+ transporting kinetics. The RMSPEis constructed via polymerization-induced phase separation based on a rational combination of lithiophilic components and rigid/flexible chain units with significant hydrophobic/hydrophilic contrasts. Further refined by coating a robust polymer network, this all-organic design endows a homogenous micro-nano porous structure, providing a novel framework favorable for rapid ion transport in both its soft interfacial and bulk phases. The RMSPE exhibited excellent ion conductivity of 1.91 mS cm-1 at room temperature and a high Li+ transference number of 0.7. Assembled symmetrical Li cells realized stable cycling for over 2400 h at 3.0 mA cm-2. LiFePO4 full batteries demonstrated a long lifespan of 3300 cycles with a capacity retention of 93.5% and stable cycling performance at -35 °C. This innovative design concept offers a promising perspective for achieving high-performance polymer-based Li metal batteries.

Experimental investigation of the impact of additives in low clinker cementitious materials on multi-ion transference numbers and diffusion coefficients

In this paper, multi-ion transference numbers were determined throughout the chloride migration testing of low clinker cement-based materials. For this purpose, five cement pastes were studied: pure Portland paste (as a reference) and four other pastes, based on limestone filler, fly ash, slag or silica fume. The transference numbers were calculated from the concentration evolution in the three zones of the migration cell (catholyte, anolyte and sample), considering that: (i) ions moved in the catholyte and anolyte; (ii) ions leached from the sample; (iii) ions were generated from the electrode processes, and (iv) the pore solution of the sample evolved during the test. The chloride transference numbers of pastes with pure Portland cement, limestone filler, fly ash, slag or silica fume are almost zero at the beginning of the migration test but 0.23; 0.18; 0.06; 0.05 and 0.20 at the end of the test, respectively. The ion transference numbers obtained were used for the calculation of diffusion coefficients of chlorides, sodium and potassium using the Nernst-Einstein equation.

Molecular Design of Solid Polymer Electrolytes with Enthalpy-Entropy Manipulation for Li Metal Batteries with Aggressive Cathode Chemistry.

Solid polymer electrolytes (SPEs) with high ion conductivity, high Li+ transference number, and a wide electrochemical window are promising for the next-generation high-energy Li metal batteries (LMBs). Here we describe an enthalpy-entropy manipulation strategy enabling a class of polycarbonate-based copolymeric electrolytes (PCCEs) with regulated cation/anion solvation via a molecular design of the polymer backbone. By integrating a weakly solvating linear carbonate with another strongly solvating cyclic carbonate segment in the polymer backbone, the cation-dipole coordination for Li+ ions (with two types of carbonyl groups) is weakened (low enthalpy penalty) and nondirectional (high entropy penalty), which enables a weak solvation and rapid diffusion of Li+. We further introduce a bis-acrylamide-based cross-linking segment which, other than imparting high mechanical strength, exhibits dihydrogen bonding with the difluoro(oxalate) borate anions, which is strong (high enthalpy penalty) and directional (low entropy penalty), thus restricting the migration of anions. As a result, the PCCE delivers a high ionic conductivity of 0.66 mS cm-1 with a high Li+ transference number (0.76) at 25 °C, as well as high oxidation stability. By an in situ polymerization approach, the PCCE enables LMBs using high-nikel LiNi0.8Co0.1Mn0.1O2 cathodes with a high capacity retention of 82.2% over 800 cycles with a cutoff voltage of 4.5 V and further LMBs using aggressive LiNi0.5Mn1.5O4 cathodes with a 96.4% capacity retention over 300 cycles with a cutoff voltage of 5.0 V. The described enthalpy-entropy manipulation approach offers a unique perspective for the molecular design of high-performance SPEs for high-energy Li metal batteries.

Anion-Anchored Polymer-in-Salt Solid Electrolyte for High-Performance Zinc Batteries.

Solid polymer electrolytes hold promise for addressing key challenges in rechargeable zinc batteries (ZBs) utilizing aqueous electrolytes. However, achieving simultaneous high ionic conductivity, excellent mechanical strength, and a high cation transference number while effectively suppressing Zn dendrites remains challenging. Herein, we design a novel polymer-in-salt solid electrolyte (PISSE) composed of polyacrylonitrile (PAN), zinc chloride (ZnCl2), and niobium pentoxide with oxygen vacancies (Nb2O5-x) with high ionic conductivity. PAN polymer matrix provides the electrolyte good mechanical properties and solubility of Zn salt. The high concentration of ZnCl2 effectively decouples the Zn2+ from polymer chain segments and provides more ionic conduction amorphous region. Moreover, incorporating Nb2O5-x filler accelerates Zn2+ desolvation by anchoring (ZnxCly)2x-y clusters and enhances the system's mechanical properties, achieving a superior Zn2+ transference number (~0.93) and interfacial stability. Consequently, the optimized PISSE demonstrates exceptional stability during prolonged cycling periods, wide temperature range operation (-40 ℃ to 60 ℃), remarkable flexibility, and compatibility with diverse electrode materials. This study provides valuable insights into the design of solid-state electrolytes based on ZBs and elucidates their multifunctional prospects.

Constructing Donor–Acceptor-Linked COFs Electrolytes to Regulate Electron Density and Accelerate the Li+ Migration in Quasi-Solid-State Battery

HighlightsDonor–acceptor-linked covalent organic framework (COF)-based electrolyte can not only fulfill highly-selective Li+ conduction, but also offer a crucial opportunity to understand the role of electronic density in quasi-solid-state Li metal batteries.Donor–acceptor-linked COF electrolyte results in Li+ transference number 0.83, high ionic conductivity 6.7 × 10–4 S cm−1 and excellent cyclic ability in Li metal batteries.In situ characterizations, density functional theory calculation and time-of-flight secondary ion mass spectrometry are adopted to expound the mechanism of the rapid migration of Li+ in the “donor–acceptor” electrolyte system.

Ionic liquid supported chitosan-g-SPA as a biopolymer-based single ion conducting solid polymer electrolyte for energy storage devices

This article discusses the preparation of different grades of single-ion conducting quasi-solid polymer electrolytes (q-SPE) material (Chit-g-SPA-IL) based on biopolymer (chitosan), polyacrylic acid and DBU-acetate (DBUH+ AcO−) ionic liquid. Chit-SPA-60 %-IL exhibited the highest conductivity within the range of 10−4 S/cm. TGA analysis demonstrated the stability of electrolytes up to a temperature of 120 °C. SEM-EDS analysis unveiled the porous nature of the electrolyte and even distribution of ions throughout the matrix. It exhibited an electrochemical stability window (EWS) of 2.53 V with significant current density and an ionic transference number (ITN) of ~99.9 %. The temperature-dependent conductivity established an Arrhenius-type conduction mechanism with an activation energy of 0.149 eV for ion movement within the electrolyte matrix. The AC conductivity analysis emphasized the time-temperature independence of the ionic conduction mechanism. Dielectric analysis highlighted the capacitive nature of the electrolyte, underlining its substantial capacitance, while modulus studies indicated minimal influence from the electrode-electrolyte interface. Chit-SPA-60 %-IL at 30 °C included a self-diffusion coefficient of 4.57 × 10−5 m2/s, ionic mobility of 1.75 × 10−3 m2/Vs, and drift ionic velocity of 0.44 m/s. These findings makes SPE as a promising candidate for sodium-ion-based energy storage devices.

Enhanced oxygen evolution and power density of Co/Zn@NC@MWCNTs for the application of zinc-air batteries

Rechargeable zinc-air batteries (ZABs) are viewed as a promising solution for electric vehicles due to their potential to provide a clean, cost-effective, and sustainable energy storage system for the next generation. Nevertheless, sluggish kinetics of the oxygen evolution reaction (OER), the oxygen reduction reaction (ORR) at the air electrode, and low power density are significant challenges that hinder the practical application of ZABs. The key to resolving the development of ZABs is developing an affordable, efficient, and stable catalyst with bifunctional catalytic. In this study, we present a series of bifunctional catalysts composed of Co/Zn nanoparticles uniformly embedded in nitrogen-doped carbon (NC) and multi-walled carbon nanotubes (MWCNTs) denoted as Co/Zn@NC@MWCNTs. The incorporation of MWCNTs using a facile and non-toxic method significantly decreased the overpotential of the OER from 570 to 430 mV at 10 mA cm−2 and the peak power density from 226 to 263 mW cm−2. Besides, the electrochemical surface area measurements and electrochemical impedance spectroscopy indicate that the three-dimensional (3D) network structure of MWCNTs facilitates mass transport for ORR and reduces electron transfer resistance during OER, leading to a small potential gap of 0.86 V between OER and ORR, high electron transfer number (3.92–3.98) of the ORR, and lowest Tafel slope (47.8 mV dec−1) of the OER in aqueous ZABs. In addition, in-situ Raman spectroscopy revealed a notable decrease in the ID/IG ratio for the optimally configured Co/Zn@NC@MWCNTs (75:25), indicating a reduction in defect density and improved structural ordering during the electrochemical process, which directly contributes to enhanced ORR activity. Hence, this study provides an excellent strategy for constructing a bifunctional catalyst material with a 3D MWCNTs conductive network for the development of advanced ZAB systems for sustainable energy applications.

FFF/FDM 3D-Printed Solid Polymer Electrolytes Based on Acrylonitrile Copolymers for Lithium-Ion Batteries.

Lithium-ion batteries (LIBs) are essential in modern electronics, particularly in portable devices and electric vehicles. However, the limited design flexibility of current battery shapes constrains the development of custom-sized power sources for advanced applications like wearable electronics and medical devices. Additive manufacturing (AM), specifically Fused Filament Fabrication (FFF), presents a promising solution by enabling the creation of batteries with customized shapes. This study explores the use of novel poly(acrylonitrile-co-polyethylene glycol methyl ether acrylate) (poly(AN-co-PEGMEA)) copolymers as solid polymer electrolytes for lithium-ion batteries, optimized for 3D printing using FFF. The copolymers were synthesized with varying AN:PEGMEA ratios, and their physical, thermal, and electrochemical properties were systematically characterized. The study found that a poly(AN-co-PEGMEA) 6:1 copolymer ratio offers an optimal balance between printability and ionic conductivity. The successful extrusion of filaments and subsequent 3D printing of complex shapes demonstrate the potential of these materials for next-generation battery designs. The addition of succinonitrile (SCN) as a plasticizer significantly improved ionic conductivity and lithium cation transference numbers, making these copolymers viable for practical applications. This work highlights the potential of combining polymer chemistry with additive manufacturing to provide new opportunities in lithium-ion battery design and function.

Stable Efficient Solid-State Supercapacitors and Dye-Sensitized Solar Cells Using Ionic Liquid-Doped Solid Biopolymer Electrolyte.

As synthetic and nonbiodegradable compounds are becoming a great challenge for the environment, developing polymer electrolytes using naturally occurring biodegradable polymers has drawn considerable research interest to replace traditional aqueous electrolytes and synthetic polymer-based polymer electrolytes. This study shows the development of a highly conducting ionic liquid (1-hexyl-3-methylimidazolium iodide)-doped corn starch-based polymer electrolyte. A simple solution cast method is used to prepare biopolymer-based polymer electrolytes and characterized using different electrical, structural, and photoelectrochemical studies. Prepared polymer electrolytes are optimized based on ionic conductivity, which shows an ionic conductivity as high as 1.90 × 10-3 S/cm. Fourier transform infrared spectroscopy (FTIR) confirms the complexation and composite nature, while X-ray diffraction (XRD) and polarized optical microscopy (POM) affirm the reduction of crystallinity in biopolymer electrolytes after doping with ionic liquid (IL). Thermal and photoelectrochemical studies further affirm that synthesized material is well stable above 200 °C and shows a wide electrochemical window of 3.91 V. The ionic transference number measurement (t ion) confirms the predominance of ionic charge carriers in the present system. An electric double-layer capacitor (EDLC) and a dye-sensitized solar cell (DSSC) were fabricated by using the highest conducting corn starch polymer electrolyte. The fabricated EDLC and DSSC delivered an average specific capacitance of 130 F/g and an efficiency of 1.73% in one sun condition, respectively.

Transference Numbers and Ion Coordination Strength for Mg2+, Na+, and K+ in Solid Polymer Electrolytes.

In solid polymer electrolytes, the transference number (T i ) is fundamental for performance as it defines the transport efficiency of the electrochemically active species. For systems "beyond Li", a lack of suitable methods to determine the T i is limiting the understanding of the ion transport in such systems. In this study, a method based on electrophoretic NMR (eNMR) and electrochemical impedance spectroscopy (EIS) is used to determine the T + for Na+, K+, and Mg2+ in poly(ε-caprolactone) (PCL), comparing this to previous results in poly(ethylene oxide). In common for all cations, a distinct correlation between strong coordination and a low T + is observed. Paradoxically, however, the divalent Mg2+ in PCL displayed a T + of 0.86 compared to ∼0.5 for the monovalent cations. Persistent clustering in this system suggests that it is better treated as a monovalent [MgTFSI]+ + TFSI- system, resulting in a T + of the [MgTFSI]+ cation of 0.43. These results serve as a door opener for the wide applicability of the eNMR/EIS method in order to provide an understanding of charge transport in multivalent systems.