Electrolysis Conditions Research Articles

Synthesis of Porous Anodic Alumina Featuring a Periodic Pore Structure by Regulating the Anode Temperature

Abstract Porous anodic alumina (PAA) with a periodic pore structure has been synthesized by using an innovative preparation method. The morphology of PAA pores can be modulated within the same electrolyte by adjusting the temperature of the aluminum anode, enabling periodic variations in pore size (Dp). The formation mechanism of PAA has been elucidated through analyses of micromorphology, anodization current density (ia), interpore distance (Dint), and Dp of the samples. Results indicate that the average Dint for the synthesized PAA is approximately 260–340 nm, while the average Dp ranges from 90 to 260 nm. Both ia and Dp exhibit periodic fluctuations corresponding to changes in anode temperature under consistent electrolyte conditions and anodization voltage (Ua). Lateral pores are generated via a phosphoric acid etching process, resulting in PAA with a distinctive three-dimensional interconnected pore architecture. Furthermore, ridges with an arc-like shape on the outer walls of PAA pores have been observed; their formation mechanism can be effectively explained by the convection model and the viscous flow model. These findings contribute significantly to achieving precise control over the pore structure of PAA.

Electrochemically Controlled Deposition of Low-Crystalline Covalent Organic Frameworks on Nanocarbon Electrode Toward Metal-Free Oxygen Reduction Electrocatalyst.

Morphology-controlled synthesis of covalent organic frameworks (COFs) offers significant potential for electrochemical applications. However, controlling the deposition of nanometer-scale COFs on carbon supports remains challenging due to the need for a slow COF generation rate and the dispersion of carbon supports in liquid-phase synthesis. In this study, nanometer-scale COF/carbon composites are fabricated using electrochemically generated acid (EGA) to assist in the formation of imine-type COFs, which are then deposited onto pre-cast nanocarbon supports on an electrode. A monomer combination of tri(4-aminophenyl)-1,3,5-triazine and 2,5-dimethoxybenzene-1,4-dicarboxaldehyde is utilized due to their suitable oxidation potentials, with 1,2-diphenylhydrazine serving as the EGA source. Through proton generation driven by electrolysis conditions, controlled COF formation is achieved at the single nanometer scale, ranging from 6 to 30nm, on various nanocarbon supports. The COF/carbon electrode is evaluated as an oxygen reduction reaction (ORR) electrocatalyst, demonstrating superior performance compared to other COF-based electrode materials containing the 1,3,5-triazine moiety. The findings experimentally validate the efficacy of the EGA-assisted COF deposition method for nanostructure construction and its ability to enhance the properties of COF-based electrodes through morphology tuning.

Design of Janus Heterostructures Embedded in Carbon Nanofibers via Heterointerface and Structural Engineering for Rapid Polysulfide Conversion

AbstractThe sluggish redox kinetics of sulfur electrode and the “shuttle effect” caused by soluble lithium polysulfides (LiPS) are critical challenges in the advancement of high‐energy lithium‐sulfur batteries. Here, a pioneering flexible self‐supporting composite scaffold that incorporates Janus V2O3/VN heterostructures embedded within multichannel nitrogen‐doped carbon nanofibers (MNCNF) is introduced. The MNCNF features a 3D hierarchical porous conductive network that facilitates rapid ion/electron transport while offering substantial space for high sulfur loading. Theoretical calculations demonstrate that the Janus V2O3/VN heterocatalyst, featuring a built‐in interfacial electric field, facilitates a smooth and rapid “capture‐diffusion‐conversion” of LiPS by leveraging the V2O3’s strong adsorption capacity, VN's high catalytic capability and promoted interfacial charge/ion transport, thereby accelerating bi‐directional sulfur conversion. The as‐designed sulfur electrode with a sulfur loading of 2.0 mg cm−2 showcases high rate capability of 618 mAh g⁻¹ at 5C with 68.1% capacity retention over 500 cycles. Notably, under harsh conditions of high sulfur loading (6.0 mg cm−2) and lean electrolyte (7.5 µL mg−1), it achieves a high initial areal capacity of 4.92 mAh cm−2 with 94.8% capacity retention over 150 cycles. This work offers valuable insights for the rational design of optimal vanadium‐based heterocatalysts aimed at facilitating rapid sulfur redox conversion.

Effect of Anion-Conducting Electrolytes in Pore-Filling Membranes on Performance and Durability in Water Electrolysis

This study examines the effect of the structural characteristics of anion-conducting monomers within pore-filling anion exchange membranes on the performance and durability of anion exchange membrane water electrolysis. Analysis reveals that acrylamide- and acrylate-based membranes show optimal performance without methyl groups, with acrylamide-based membranes outperforming their acrylate counterparts in current density, particularly at 1.8 V. The AC-AA and AC-MAA monomers demonstrate durability, with AC-MAA showing enhanced alkaline stability, likely due to the presence of a methyl group, resulting in an increase rate of 746.6 μV/h compared to AC-AA’s 1150 μV/h. This study also shows that a commercial membrane exhibits a decrease rate of 3116 μV/h, underscoring the pore-filling membrane’s superior durability. Furthermore, the findings highlight that pore-filling membrane technology enables better durability and performance in electrolysis environments compared to the commercial homogeneous membrane, particularly when alkaline conditions are present. This research provides a foundation for designing high-performance, durable membranes for efficient hydrogen production, particularly under water electrolysis conditions.

Characterization of Diffusioosmotic Ion Transport for Enhanced Concentration-Driven Power Generation via Charge Heterogeneity in Nanoporous Membranes.

Nanoscopic mass/ion transport through heterogeneous nanostructures with various physicochemical environments occurs in both natural and artificial systems. Concentration gradient-driven mass/ion transport mechanisms, such as diffusioosmosis (DO), are primarily governed by the structural and electrical features of the nanostructures. However, these phenomena under various electrical and chemical conditions have not been adequately investigated. In this study, we fabricated a pervaporation-based particle-assembled membrane (PAM)-integrated micro-/nanofluidic device that facilitates easy tuning of the surface charge heterogeneity in nanopores/nanochannels. The nanochannels in the device consisted of two heterogeneous and in-series PAMs. The device was used to quantitatively measure electric signals generated by DO within the nanochannels with a single electrolyte or a combination of two electrolytes. Then, we characterized ion transport by changing surface charge heterogeneity and applying various electrolytic conditions, characterizing the concentration-driven power generation under these conditions. We found that not only does the charge heterogeneity provide additional resistance to ion transport but also the manipulation of the heterogeneity enables the effective modulation of ion transport and optimization of concentration-driven power generators regarding ion selectivity. In conjunction with the surface charge heterogeneity, the electrolytic conditions significantly affected the net flux of ion transport by enhancing or even negating the ion selectivity. Hence, we anticipate that both the platform and results will provide a deeper understanding of ion transport in nanostructures within complex environments by optimizing and improving practical concentration-driven applications, such as energy conversion/harvesting, molecular focusing/separation, and ionic diodes and memristors.

Non-Aqueous Electrochemical CO2 Reduction to Multivariate C2-Products Over Single Atom Catalyst at Current Density up to 100mAcm-2.

Electrochemical CO2 reduction reaction (CO2-RR) in non-aqueous electrolytes offers significant advantages over aqueous systems, as it boosts CO2 solubility and limits the formation of HCO3 - and CO3 2- anions. Metal-organic frameworks (MOFs) in non-aqueous CO2-RR makes an attractive system for CO2 capture and conversion. However, the predominantly organic composition of MOFs limits their electrical conductivity and stability in electrocatalysis, where they suffer from electrolytic decomposition. In this work, electrically conductive and stable Zirconium (Zr)-based porphyrin MOF, specifically PCN-222, metalated with a single-atom Cu has been explored, which serves as an efficient single-atom catalyst (SAC) for CO2-RR. PCN- 222(Cu) demonstrates a substantial enhancement in redox activity due to the synergistic effect of the Zr matrix and the single-atom Cu site, facilitating complete reduction of C2 species under non-aqueous electrolytic conditions. The current densities achieved (≈100mAcm- 2) are 4-5 times higher than previously reported values for MOFs, with a faradaic efficiency of up to 40% for acetate production, along with other multivariate C2 products, which have never been achieved previously in non-aqueous systems. Characterization using X-ray and various spectroscopic techniques, reveals critical insights into the role of the Zr matrix and Cu sites in CO2 reduction, benchmarking PCN-222(Cu) for MOF-based SAC electrocatalysis.

Electrochemistry of Pt and Pd Under Pulse Electrolysis Conditions

Platinum and palladium are the most suitable electrode materials for studying the kinetics and mechanism of various electrochemical processes. Consequently, their behavior in electrochemical systems has been the subject of extensive study. However, the effect of pulse alternating current (PAC) on Pt and Pd in aqueous electrolytes represents a relatively new area of research for electrochemical process technologies. It was demonstrated that employing PAC with a frequency of 50 Hz to platinum in NaOH electrolyte result in the formation of Pt particles (7.6 nm) containing a PtOx phase (0.25 ± 0.03 wt%). The dissolution of platinum in NaCl electrolyte resulted in the formation of only platinum chloride complexes. The palladium in the NaOH electrolyte was passivated when PAC was employing to Pd electrodes. In the NaCl electrolyte, the formation of Pd-PdO particles (42 ± 2 wt% of PdO) was observed. The crystallite size for Pd and PdO was 7.9 and 1.99 nm, respectively. The discrepancy in the chemical properties of two metals belonging to the transition metals of group VIII of the periodic system, which are characterized by the same space group (Fm3m), can be attributed to the combination of electronic and redox properties of Pt and Pd.

An Electrochemical Screening Reactor Kit for Rapid Optimization of Electrosynthesis Applications

Electrosynthetic processes powered by renewable energy present a viable solution to decarbonize chemical industry, while producing essential chemical products for modern society. However, replacing well‐established thermocatalytic methods with renewable‐powered electrosynthesis requires cost‐efficient and highly optimized systems. Current optimization of electrolysis conditions towards industrial applications involving scalable electrodes is time consuming highlighting the necessity for the development of electrochemical setups for aimed at rapid and material efficient testing. Thus, we introduce a 3D printed electrochemical screening reactor designed for rapid optimization of relevant electrochemical parameters, utilizing electrode and membrane materials comparable to those in scalable electrolyzers. The reactor comprises eight individual two‐compartment cells that can be operated simultaneously and independently. To evaluate the reactor’s ability to provide meaningful insights on scalable cell designs, trends were compared with data from conventional scalable systems for electrochemical hydrogenations (EChH), demonstrating fast and accurate parameter optimization with the screening reactor. A detailed description of the reactor design and construction data files using open‐source tool are provided, enabling easy modification for anyone. We believe this screening reactor will be a valuable tool for the scientific community, for facilitating the discovery of reactions with customized electrode designs and rapidly improving conditions in established large‐scale electrolyzers.

Constructing valid Li+ fast-transfer channels on novel P(TPC@Lys-Li) separator to enable security, high energy density, and controllable Li dendrites for lithium-metal batteries

Lithium metal batteries (LMBs) attract widespread attention under current high energy density developments. However, wild Li dendrite propagations owing to chaotic Li depositions raise challenges for LMB blossoming. Separators with specific demands thus should be involved when smoothly transferring into LMBs. In this research, a fascinating P(TPC@Lys-Li) separator is prepared by the turbulent interfacial polymerization and electrospinning to ingeniously clarify dependencies of Li+ transfer dynamics on double electric layer thickness (DELT) regulations within porous skeletons. P(TPC@Lys-Li) enables negatively charged porous skeleton surface and compresses DELT, which constructs high-efficiency Li+ fast-transfer channels on porous skeletons and accelerates Li+ transfer speed by 18.3 times. Especially, P(TPC@Lys-Li) supplies extra Li+ for stable formations of solid electrolyte interphase (SEI) layer, homogenizing nucleation and growth behaviors during Li depositions. Remarkable C-rate capacity and cycle stability thus arise for assembled LMBs, holding 87.2 % capacity retention after 700 cycles at 0.5C even under high cathode loading and lean electrolyte conditions. P(TPC@Lys-Li) also maintains constant physical scale and unabated mechanical strength even at elevated temperatures approaching 200 °C, which provides excellent battery security as LMBs encounter uncontrollable thermal runaway. Above attractive features enable P(TPC@Lys-Li) separator to be potentially applied in LMBs demanding sufficient security, high-capacity density, and fast charge technology.

Favorable Moderate Adsorption of Polysulfide on FeNi3 Intermetallic Compound Accelerating Conversion Kinetics for Advanced Lithium-Sulfur Batteries.

Sluggish conversion kinetics of polysulfides during discharge and the severe shuttle effect significantly hinder the practical application of lithium-sulfur (Li-S) batteries. In this work, the lattice engineering strategy of Fe hybridization is employed to manipulate the bulk phase spacing of FeNi3 (space group Pm3m) intermetallic compounds to adjust the 3d electronic structure, optimizing the adsorption of polysulfides, thereby accelerating the catalytic conversion. As a result, FeNi2.25@OC achieves favorable moderate adsorption toward polysulfides. Due to the larger number of electrons occupying the lowest occupied molecular orbital of Li2S4, the S-S bonds are weakened and broken. Temperature-dependent experiments confirm that FeNi2.25@OC exhibits the lowest activation energy and can effectively accelerate the catalytic conversion of polysulfides. The Li-S cell assembled with FeNi2.25@OC modified PP separator delivers a high initial discharge specific capacity of 1219.5 mAh g-1 at 0.2 C. Even at a high sulfur loading of 6.06mg cm-2 and lean electrolyte conditions (6 µL mg-1), it can cycle stably for 60 cycles.

Pitfall on the interpretation of double layer capacitance increase after accelerated stress test of hydrogen evolution reaction on NiMo catalysts

Critical investigation of methods used to screen the catalytic activity of different electrocatalysts is crucial for the development of water electrolysis technology. One of such protocols to justify the catalytic activity trend among different catalysts involves determining their electrochemically active surface area (ECSA) which is usually estimated from non-Faradic double layered capacitance (Cdl) of the catalyst material. Furthermore, catalytic current normalized with ECSA is frequently used to gain insight into the intrinsic activity of a catalyst. Since not all the metallic catalysts are highly stable under the electrolysis conditions, it is highly important, though rarely explored, to investigate whether or not the adsorption/desorption of leached/dissolved multivalent metal ions influences the measurement of non-Faradic Cdl. Here, we explore the possible influence of Mo leached from NiMo alloy on the measured Cdl of NiMo. Using cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS), Cdl of NiMo alloy was measured before and after carrying out long term (chronopotentiometric and CV cycling) hydrogen evolution reaction (HER) in alkaline conditions. After extended HER testing, we observe a notable rise (∼22 % averaging all our experiments) in the Cdl of NiMo alloy when measured with traditional methods. Interestingly, only 8 % of this increase can be attributed to an expansion in surface area. We hypothesize that the majority of the increase in Cdl stems from the higher amount of charges stored through leached multivalent ions, which accumulate within surface cavities.

Palladium (II) pyridylidene sulfonamides (PYSAs) for electrocatalytic reduction of CO2

A new class of donor flexible nitrogen ligands, namely pyridylidene sulfonamides (PYSAs; N-(1-benzylpyridin-4(1H)-ylidene)benzene-sulfonamide, N-(1-benzylpyridin-4(1H)-ylidene)thiophene-2-sulfonamide, N-(1-benzylpyridin-4(1H)-ylidene)pyridine-2-sulfonamide and N-(1-benzylpyridin-4(1H)-ylidene)-8-quinoline-sulfonamide), were prepared from 4-amino-1-benzylpyridin-1-ium chloride and various aromatic sulfonyl chlorides. The treatment of PYSAs with [(CH3CN)2PdCl2] afforded the corresponding Pd(II) complexes. The newly synthesized compounds were characterized by multinuclear 1H and 13C NMR spectroscopy, IR spectroscopy, elemental analysis, and single-crystal X-ray diffraction. Their redox chemistry was then evaluated under an inert atmosphere of nitrogen and carbon dioxide, both in the presence and absence of protons. An apparent interaction of CO2 with each Pd(II) catalyst was inferred by the collection of cyclic voltammograms and the enhancement of peak currents at respective peak potentials. All catalysts were robust under bulk electrolysis conditions over 3600 s.

Pore-Scale Visualized Transport and Retention of Fibrous and Fragmental Microplastics in Porous Media under Various Surfactant Conditions.

For advancing current knowledge on the transport of microplastics (MPs) in the environment, this study used a real-time pore-scale visualization and quantitative system to examine the motions and mobility of fibrous and fragmental MPs under various surfactant (AEO, CTAC, and AES) and electrolyte conditions. The videos showed that fibrous MPs formed tangles through entanglement, which moved in an axial direction aligned with the flow streamline. Both fibrous and fragmental MPs showed suspended movement as well as surface movement (e.g., sliding, rolling, and saltating) in the porous media. Some deposited fibrous MPs showed flexible deformation due to shear flow. Compared to fragmental MPs, fibrous MPs showed lower mobility due to the tendency to deposit and clog the porous media. The mobility of fragmental MPs was enhanced in the presence of AEO but remained relatively unchanged with AES. In the presence of CTAC, the mobility of fragmental MPs was slightly inhibited under low ionic strength (IS) conditions but remarkably enhanced under high IS conditions. However, the mobility of fibrous MPs was largely unaffected by the surfactants. Both the numerical model and FDLVO calculations effectively described the transport and deposition of MPs in porous media.

Highly Solvating Electrolytes with Core‐Shell Solvation Structure for Lean‐Electrolyte Lithium‐Sulfur Batteries

The practical energy density of lithium‐sulfur batteries is limited by the low sulfur utilization at lean electrolyte conditions. The highly solvating electrolytes (HSEs) promise to address the issue at harsh conditions, but the conflicting challenges of long‐term stability of radical‐mediated sulfur redox reactions (SRR) and the poor stability with lithium metal anode (LMA) have dimmed the efforts. We now present a unique core‐shell solvation structured HSE formulated with classical ether‐based solvents and phosphoramide co‐solvent. The unique core‐shell solvation structure features confinement of the phosphoramide in the first solvation shell, which prohibits severe contact reactions with LMA and endows prolonged stability for [S3]•– radical, favoring a rapid radical‐mediated solution‐based SRR. The cell with the proposed electrolyte showing a high capacity of 864 mA h gsulfur−1 under high sulfur loading of 5.5 mgsulfur cm−2 and low E/S ratio of 4 µL mgsulfur−1. The strategy further enables steady cycling of a 2.71‐A h pouch cell with a high specific energy of 307 W h kg−1. Our work highlights the fundamental chemical concept of tuning the solvation structure to simultaneously tame the SRR and LMA stability for metal‐sulfur batteries wherein the electrode reactions are heavily coupled with electrolyte chemistry.

Highly Solvating Electrolytes with Core-Shell Solvation Structure for Lean-Electrolyte Lithium-Sulfur Batteries.

The practical energy density of lithium-sulfur batteries is limited by the low sulfur utilization at lean electrolyte conditions. The highly solvating electrolytes (HSEs) promise to address the issue at harsh conditions, but the conflicting challenges of long-term stability of radical-mediated sulfur redox reactions (SRR) and the poor stability with lithium metal anode (LMA) have dimmed the efforts. We now present a unique core-shell solvation structured HSE formulated with classical ether-based solvents and phosphoramide co-solvent. The unique core-shell solvation structure features confinement of the phosphoramide in the first solvation shell, which prohibits severe contact reactions with LMA and endows prolonged stability for [S3]•- radical, favoring a rapid radical-mediated solution-based SRR. The cell with the proposed electrolyte showing a high capacity of 864 mA h gsulfur-1 under high sulfur loading of 5.5 mgsulfur cm-2 and low E/S ratio of 4 µL mgsulfur-1. The strategy further enables steady cycling of a 2.71-A h pouch cell with a high specific energy of 307 W h kg-1. Our work highlights the fundamental chemical concept of tuning the solvation structure to simultaneously tame the SRR and LMA stability for metal-sulfur batteries wherein the electrode reactions are heavily coupled with electrolyte chemistry.

Electrooxidative C(sp3)-H Cyanation of Sparteine and Lupanine in Undivided Batch and Continuous-Flow Cells.

Sparteine is widely used as a chiral ligand in asymmetric synthesis, but methods for providing efficient access to functionalized sparteine derivatives are still limited. Herein, we describe an electrochemical α-cyanation of sparteine-type bis-quinolizidine alkaloids. This method features commercially available setups for batch and single-pass continuous flow conditions, enabling easy gram scale synthesis of valuable racemic and enantiopure products. Moreover, insights into the selectivity of the reaction and overoxidation mechanisms are disclosed. This allows for the development of divergent oxidation pathways depending on the electrolysis conditions.

Enhanced Stability of N‐Type Organic Electrochemical Transistors Via Small‐Molecule Passivation

AbstractOrganic electrochemical transistors (OECTs) are of great interest owing to their potential applications in bioelectronics and neuromorphic systems. However, n‐type OECTs suffer from poor stability and facile degradation, mainly due to the oxygen reduction reactions in organic mixed ionic‐electronic conductors during device operation. In this study, a small‐molecule passivation strategy is introduced to greatly improve the stability of poly(benzobisimidazobenzophenanthroline) (BBL)‐based n‐type OECTs. 6,6‐Phenyl‐C61‐butyric acid methyl ester (PCBM) is spin‐coated onto the BBL layer to form a smooth and hydrophobic passivation layer, which effectively inhibits the oxygen reduction reactions while enabling ion permeation in aqueous electrolytes. Consequently, the OECTs employing the PCBM/BBL bilayers with an optimized PCBM thickness exhibit significantly improved operational stability at various electrolyte conditions (0.1 m NaCl or NaOH) and over a wide gate‐voltage sweep range (from −0.7 to 0.7 V). Owing to the high electron mobility of PCBM, the carrier mobility and switching speed of the PCBM/BBL OECTs are also improved compared with those of the pristine BBL OECTs. This study demonstrates the beneficial effects of simple surface passivation in organic mixed ionic‐electronic conductors and provides valuable insights for the design of high‐performance and stable OECTs for more specialized and advanced applications.

Insight into the roles of Cl− for the degradation of acid Red 14 in an electrochemical advanced oxidation system: Mechanisms and DFT studies

Textile wastewater was typically characterized by high concentrations of chloride ions, with Acid Red 14 (AR14) representing a significant pollutant. Nevertheless, research into the degradation of AR14 by electrochemical advanced oxidation processes (EAOPs) had largely overlooked the influence of chloride ions. In this regard, the EC-Clorine-MMO/Ti system was designed, and the degradation mechanism of AR14 was subjected to meticulous investigation. The adopted anode was composed of Ti/IrO2-Ta2O5 (mixed metal oxide, MMO). It demonstrated superior efficiency in degrading AR14 within a sodium chloride (NaCl) electrolyte, registering an apparent kinetic constant rate approximately 16.76 times greater than that observed within a sodium perchlorate (NaClO4) electrolyte. The optimal chloride ion concentration was identified as 0.04 mol/L. Besides, alkaline conditions were not conducive to the degradation of AR14. It was noteworthy that the electrochemical byproducts chlorite (ClO2−), chlorate (ClO3−), perchlorate (ClO4−), and trihalomethane (THMs) were not produced in the solution treated by the EC-Clorine-MMO/Ti system. Electron paramagnetic resonance (EPR) spectroscopy, probe, and quenching experiments identified that hydroxyl radicals (•OH), superoxide radicals (O2•−), and dichloride radicals/chlorine monoxide radicals (Cl2•−/ ClO•) were the major reactive species. Of these, •OH played a pivotal role in AR14 degradation. Additionally, the three principal degradation pathways of AR14 were deduced by LC-MS analysis, UV–vis spectra, density-functional theory (DFT) calculations, and excitation-emission matrix (EEM) fluorescence spectroscopy. Furthermore, the generation mechanism of reactive species and the proposed mechanism of AR14 degradation by the EC-Clorine-MMO/Ti system were presented. The study made a significant contribution to the understanding of the electrochemical reactions occurring in textile wastewater and provided valuable insights into the rational control of electrolytic conditions for the treatment of saline wastewater.

Spatial structure design of interlayer for advanced lithium–sulfur batteries

The practical application of lithium-sulfur (Li–S) batteries has been hindered by the lithium polysulfide shuttle effect. An effective way to solve this problem is to utilize interlayer engineering to confine polysulfides and promote their catalytic conversion. From a spatial perspective, we designed a carbon nanofiber conductive layer (CNF, without Sn content, labeled as 0) and two Sn-doped carbon nanofiber catalytic layers (SCNF, with 10 wt% and 20 wt% Sn content, labeled as 1 and 2, respectively) with different contents of catalyst content, and verified an efficient interlayer structure by adjusting the order of preferential contact between the conductive layer and the catalytic layer with the sulfur cathode to form a hierarchical system for the inhibition and conversion of lithium polysulfide. Electrochemical measurements show that different spatial configurations have significant discrepancies on the electrochemical performance of Li–S batteries. Thus, the space configuration of 210 enables the Li–S battery to provide a specific capacity of up to 1088 mAh g−1 after 100 cycles at 0.2C. Even under the harsh conditions of high sulfur loading (5.6 mg cm−2) and lean electrolyte (E/S = 10 μL mg−1), the Li–S battery was able to cycle stably for 94 cycles at 0.2C with 87 % capacity retention. This study provides a novel spatial strategy for advancing the spatial design of high-performance Li–S batteries.

Boosting the O2-to-H2O2 Selectivity Using Sn-Doped Carbon Electrocatalysts: Towards Highly Efficient Cathodes for Actual Water Decontamination.

The high cost and often complex synthesis procedure of new highly selective electrocatalysts (particularly those based on noble metals) for H2O2 production are daunting obstacles to penetration of this technology into the wastewater treatment market. In this work, a simple direct thermal method has been employed to synthesize Sn-doped carbon electrocatalysts, which showed an electron transfer number of 2.04 and outstanding two-electron oxygen reduction reaction (ORR) selectivity of up to 98.0 %. Physicochemical characterization revealed that this material contains 1.53 % pyrrolic nitrogen, which is beneficial for the production of H2O2, and -C≡N functional group, which is advantageous for H+ transport. Moreover, the high volume ratio of mesopores to micropores is known to favor the quick escape of H2O2 from the electrode surface, thus minimizing its further oxidation. A purpose-made gas-diffusion electrode (GDE) was prepared, yielding 20.4 mM H2O2 under optimal electrolysis conditions. The drug diphenhydramine was selected for the first time as model organic pollutant to evaluate the performance of an electrochemical advanced oxidation process. In conventional electro-Fenton process (pH 3), complete degradation was achieved in only 15 min at 10 mA cm-2, whereas at natural pH 5.9 and 33.3 mA cm-2, almost overall drug removal was reached in 120 min.