Unleashing the electrochemical performance of zirconia nanoparticles on valve-regulated lead acid battery.

The electrochemical act of valve-regulated lead acid batteries can be enhanced by conductive materials like metal oxides. This work aims to examine the preparation and influence of zirconia on poly(vinyl alcohol) based gel valve-regulated lead acid battery. Characterizations like Fourier transform infrared spectroscopy, ionic conductivity, water retention study, cyclic voltammetry, electrochemical impedance spectroscopy and galvanostatic charge-discharge techniques were done. The optimized gel system exhibited a discharge capacity of 198.45 µAh cm-2 at the current density of 0.6 mA cm-2. The battery cell with an optimized gel matrix displayed a maximum discharge capacity of 22.5 µAh at a current of 20 µA. After 500 continuous cycles, the battery attained a discharge capacity retention of 91 %. The presence of zirconia will increase the electrochemical performance of gel valve-regulated lead acid batteries.

Li3V2(PO4)3 Cathode Material: Synthesis Method, High Lithium Diffusion Coefficient and Magnetic Inhomogeneity.

Li3V2(PO4)3 cathodes for Li-ion batteries (LIBs) were synthesized using a hydrothermal method with the subsequent annealing in an argon atmosphere to achieve optimal properties. The X-ray diffraction analysis confirmed the material's single-phase nature, while the scanning electron microscopy revealed a granular structure, indicating a uniform particle size distribution, beneficial for electrochemical performance. Magnetometry and electron spin resonance studies were conducted to investigate the magnetic properties, confirming the presence of the relatively low concentration and highly uniform distribution of tetravalent vanadium ions (V4+), which indicated low lithium deficiency values in the original structure and a high degree of magnetic homogeneity in the sample, an essential factor for consistent electrochemical behavior. For this pure phase Li3V2(PO4)3 sample, devoid of any impurities such as carbon or salts, extensive electrochemical property testing was performed. These tests resulted in the experimental discovery of a remarkably high lithium diffusion coefficient D = 1.07 × 10-10 cm2/s, indicating excellent ionic conductivity, and demonstrated impressive stability of the material with sustained performance over 1000 charge-discharge cycles. Additionally, relithiated Li3V2(PO4)3 (after multiple electrochemical cycling) samples were investigated using scanning electron microscopy, magnetometry and electron spin resonance methods to determine the extent of degradation. The combination of high lithium diffusion coefficients, a low degradation rate and remarkable cycling stability positions this Li3V2(PO4)3 material as a promising candidate for advanced energy storage applications.

CdAl4O7/CdO nanocomposites: green tea extract-mediated sol-gel auto-combustion synthesis, characterization, and study as a potential hydrogen storage material.

In this article, we present the synthesis of binary CdAl4O7/CdO nanocomposites using green tea extracts and green chemistry methods for high-performance hydrogen storage. The green tea extract contains bioactive compounds (polyphenols) that act as reducing agents, which facilitate the reaction between metal ions and water. By examining the structural and morphological characteristics of the obtained substrates using scanning electron microscopy (SEM), X-ray diffraction (XRD), transmission electron microscopy (TEM), and Fourier transform infrared spectroscopy (FT-IR), it was demonstrated that the nanocomposites were successfully synthesized. We evaluated the electrochemical performance of the synthesized CdAl4O7/CdO nanocomposites using a three-electrode chronopotentiometry system. According to the results, the synthesized nanocomposites are capable of storing 1750 mAh/g of hydrogen at a constant current of 1 Amp. By using green tea extract as a natural structure-directing agent, the CdAl4O7/CdO nanocomposite can be developed more sustainably as high-performance hydrogen storage materials. Ultimately, this work contributes to the advancement of sustainable energy storage through the synthesis of a promising new material.

Mixed-Dimensional (2D/3D/3D) Heterostructured Vanadium Oxide with Rich Oxygen Vacancies for Aqueous Zinc Ion Batteries with High Capacity and Long Cycling Life.

Heterostructure engineering and oxygen vacancy engineering are the most promising modification strategies to reinforce the Zn2+ ion storage of vanadium oxides. Herein, a rare mixed-dimensional material (VOx), composed of V2O5 (2D), V3O7 (3D), and V6O13 (3D) heterostructures, rich in oxygen vacancies, was synthesized via thermal decomposition of layered ammonium vanadate. The VOx cathode provides an exceptional discharge capacity (411 mA h g-1 at 0.1 A g-1) and superior cycling stability (the capacity retention remains close to 100% after 800 cycles at 2 A g-1) for aqueous zinc-ion batteries (AZIBs). Ex situ characterizations confirm that the byproduct Zn3V2O7(OH)2·nH2O is generated/decomposed during discharge/charge processes. Furthermore, VOx demonstrates reversible intercalation/deintercalation of H+/Zn2+ ions, enabling efficient energy storage. Remarkably, a reversible crystal-to-amorphous transformation in the V2O5 phase of VOx during charge-discharge was observed. This investigation reveals that mixed-dimensional heterostructured vanadium oxide, with abundant oxygen vacancies, serves as a highly promising electrode material for AZIBs, further advancing the comprehension of the storage mechanism within vanadium-based cathode materials.

Conversion of Natural Biowaste into Energy Storage Materials and Estimation of Discharge Capacity through Transfer Learning in Li-Ion Batteries.

To simultaneously reduce the cost of environmental treatment of discarded food waste and the cost of energy storage materials, research on biowaste conversion into energy materials is ongoing. This work employs a solid-state thermally assisted synthesis method, transforming natural eggshell membranes (NEM) into nitrogen-doped carbon. The resulting NEM-coated LFP (NEM@LFP) exhibits enhanced electrical and ionic conductivity that can promote the mobility of electrons and Li-ions on the surface of LFP. To identify the optimal synthesis temperature, the synthesis temperature is set to 600, 700, and 800 °C. The NEM@LFP synthesized at 700 °C (NEM 700@LFP) contains the most pyrrolic nitrogen and has the highest ionic and electrical conductivity. When compared to bare LFP, the specific discharge capacity of the material is increased by approximately 16.6% at a current rate of 0.1 C for 50 cycles. In addition, we introduce innovative data-driven experiments to observe trends and estimate the discharge capacity under various temperatures and cycles. These data-driven results corroborate and support our experimental analysis, highlighting the accuracy of our approach. Our work not only contributes to reducing environmental waste but also advances the development of efficient and eco-friendly energy storage materials.

The effect of building arrangement on the flow characteristics in meandering compound channels.

Due to the fact that most of the cities and villages are built on the banks of the rivers, the hydraulic characteristics of water flow always undergo changes during floods, so it is necessary to study the interaction of the flood flows of meandering compound channel in these areas. In this paper, the effect of building arrangement on the flow characteristics in meandering compound channels was investigated by using laboratory models. For this purpose, a smooth floodplain (without building) and three different types of building arrangement on the floodplain including structural obstacles perpendicular and parallel to the floodplain flow and checkered structural obstacles have been used. The tests have been conducted at three relative depths of 0.29, 0.39 and 0.49 and the corresponding discharges. All experiments were performed under a quasi-uniform and fully developed flow condition. The measurement data were recorded at different sections along the meandering main channel. Stage-discharge curves, Manning's n, velocity distribution, boundary shear stress and Darcy-Weisbach friction factor are determined over 12 test runs. The results of this research show that the arrangement of buildings has a great effect on the longitudinal velocity of the main channel. At a relative depth of 0.49, in a meandering compound channel with the arrangement of structural obstacles perpendicular to the floodplain flow, the dimensionless longitudinal velocity of the main channel compared to the smooth floodplain increases by 113%, but with the arrangement of structural obstacles parallel to the floodplain flow, the dimensionless longitudinal velocity increases by 27%. Also, the building arrangement is effective in reducing the discharge capacity of the meandering compound channel, so that in a building density of 18.5%, structural obstacles perpendicular to the floodplain flow reduce the discharge capacity of the channel by 50% compared to the smooth floodplain. In the channel with structural obstacles arranged perpendicular to the floodplain flow, Manning's roughness coefficient increases sharply with increasing the relative depth, but in the channel with the structural obstacles parallel to the floodplain flow, Manning's roughness coefficient decreases with increasing the relative depth. In the channel with the arrangement of structural obstacles perpendicular to the floodplain flow, the bed shear stress of the main channel is higher than the other building arrangements, so that at the relative depth of 0.49, the average maximum bed shear stress in all sections increases by 42% compared to the smooth floodplain.

A Study on the Effect of Graphene in Enhancing the Electrochemical Properties of SnO2-Fe2O3 Anode Materials.

To enhance the conductivity and volume expansion during the charging and discharging of transition metal oxide anode materials, rGO-SnO2-Fe2O3 composite materials with different contents of rGO were prepared by the in situ hydrothermal synthesis method. The SEM morphology revealed a sphere-like fluffy structure, particles of the 0.4%rGO-10%SnO2-Fe2O3 composite were smaller and more compact with a specific surface area of 223.19 m2/g, the first discharge capacity of 1423.75 mAh/g, and the specific capacity could be maintained at 687.60 mAh/g even after 100 cycles. It exhibited a good ratio performance and electrochemical reversibility, smaller charge transfer resistance, and contact resistance, which aided in lithium-ion transport. Its superior electrochemical performance was due to the addition of graphene, which made the spherical particle size distribution more uniform, effectively lowering the volume expansion during the process of charging and discharging and improving the electrochemical cycle stability of the anode materials.

Discarded COVID-19 masks-derived-doped porous carbon for lithium-sulfur batteries.

Despite the high theoretical capacity and energy density of lithium-sulfur (Li-S) batteries, the development of Li-S batteries has been slow due to the poor electrical conductivity and the shuttle effect of the electrode materials, resulting in low sulfur utilization and fast long-term cycling capacity decay. The modified carbon materials are often used as sulfur hosts to significantly improve the cycling performance of the materials, but also bring high-cost issues. Here, the porous carbon materials are synthesized quickly and conveniently by the microwave cross-linking method using discarded medical masks as carbon sources and concentrated sulfuric acid as solvent. However, poor surface and structural properties limit the application of materials. The porous carbon material is modified with p-toluene disulfide and urea as the sulfur and nitrogen sources by the microwave cross-linking method, which not only improves the porosity and specific surface area of the porous carbon material, but also improved the electrical conductivity and interlayer spacing of the material. As synthesized SN-doped porous carbon is employed as the sulfur host, which exhibits a high discharge capacity (1349.3 mAh g-1) at 0.1°C, the S-porous C/S, N-porous C/S, and SN-porous C/S can maintain 78.1, 43.9, and 59.5% of the initial capacity after 500 cycles. The results indicate that the doping of S and N atoms provides sufficient active sites for the chemisorbed lithium polysulfides (LiPSs) to improve the reaction kinetics of the materials.

Excimer Laser-Deposited Na2/3Ni1/4Mn3/4O2 Film Cathode for Stable Sodium-Ion Battery.

Continued development of lithium-ion batteries is limited by the shortage of Li element. In this situation, the exploration of high-performance sodium-ion batteries is attracting much attention. In this experimental work, Na2/3Ni1/4Mn34O2 film cathode materials were fabricated by excimer laser deposition at different oxygen partial pressures. X-ray diffraction studies and field emission scanning electron microscopy revealed high c-axis orientation and uniform grain distribution, respectively, in the deposited films. Furthermore, after 30 cycles under a current density of 13 mA g-1, the film samples deposited at an oxygen partial pressure of 65 Pa exhibited a high capacity-retention of 91%. The film structure also had a large-current discharge performance, which makes practical applications possible.

Synergistic Double Cross-Linked Dynamic Network of Epoxidized Natural Rubber/Glycinamide Modified Polyacrylic Acid for Silicon Anode in Lithium Ion Battery: High Peel Strength and Super Cycle Stability.

Silicon (Si), a high-capacity lithium-ion battery anode material, has aroused wide attention. Its further practical application has been limited by its huge volume change during the cycle. To reduce this defect, the double cross-linked product of glycinamide hydrochloride modified poly(acrylic acid) (PAG) and epoxidized natural rubber (ENR) was developed as a water-based binder to obtain sufficient elasticity and a sufficiently strong adhesive force. Due to the double cross-linked structures in the system, the binder was enabled to effectively disperse and transfer the stress generated by the volume expansion of the Si particles and keep the integrity of the electrode during the cycle, thus obtaining excellent cycle performance. When the current density was 1 A g-1, PE55 (PAG: ENR = 1:1 cross-linked polymer) electrode still achieved a specific capacity of 2322.2 mAh g-1 after 100 cycles of constant current charge and discharge, and PE55 binder exhibited excellent bonding properties (4.45 N) and mechanical properties (stress: 5.51 MPa, strain: 87.4%). The comparison of poly(acrylic acid) (PAA) electrodes suggests that the introduction of elastic polymer and the construction of double cross-linked structures can increase the stability of Si anodes.

A Stable Core-Shell Si@SiOx/C Anode Produced via the Spray and Pyrolysis Method for Lithium-Ion Batteries.

In the critical situation of energy shortage and environmental problems, Si has been regarded as one of the most potential anode materials for next-generation lithium-ion batteries as a result of the relatively low delithiation potential and the eminent specific capacity. However, a Si anode is subjected to the huge volume expansion-contraction in the charging-discharging process, which can touch off pulverization of the bulk particles and worsens the cycle life. Herein, to reduce the volume change and improve the electrochemical performance, a novel Si@SiOx/C anode with a core-shell structure is designed by spray and pyrolysis methods. The SiOx/C shell not only ensures the structure stability and proves the high electrical conductivity but also prevents the penetration of electrolytes, so as to avoid the repetitive decomposition of electrolytes on the surface of Si particle. As expected, Si@SiOx/C anode maintains the excellent discharge capacity of 1,333 mAh g-1 after 100 cycles at a current density of 100 mA g-1. Even if the current density reaches up to 2,000 mA g-1, the capacity can still be maintained at 1,173 mAh g-1. This work paves an effective way to develop Si-based anodes for high-energy density lithium-ion batteries.

Nanocrystalline Cellulose Supported MnO2 Composite Materials for High-Performance Lithium-Ion Batteries.

The rate capability and poor cycling stability of lithium-ion batteries (LIBs) are predominantly caused by the large volume expansion upon cycling and poor electrical conductivity of manganese dioxide (MnO2), which also exhibits the highest theoretical capacity among manganese oxides. In this study, a nanocomposite of nanosized MnO2 and pyrolyzed nanocrystalline cellulose (CNC) was prepared with high electrical conductivity to enhance the electrochemical performance of LIBs. The nanocomposite electrode showed an initial discharge capacity of 1302 mAh g-1 at 100 mA g-1 and exhibited a high discharge capacity of 305 mAh g-1 after 1000 cycles. Moreover, the MnO2-CNC nanocomposite delivered a good rate capability of up to 10 A g-1 and accommodated the large volume change upon repeated cycling tests.

Electrochemical Performance of Na3V2(PO4)2F3 Electrode Material in a Symmetric Cell.

A NASICON-based Na3V2(PO4)2F3 (NVPF) cathode material is reported herein as a potential symmetric cell electrode material. The symmetric cell was active from 0 to 3.5 V and showed a capacity of 85 mAh/g at 0.1 C. With cycling, the NVPF symmetric cell showed a very long and stable cycle life, having a capacity retention of 61% after 1000 cycles at 1 C. The diffusion coefficient calculated from cyclic voltammetry (CV) and the galvanostatic intermittent titration technique (GITT) was found to be ~10-9-10-11, suggesting a smooth diffusion of Na+ in the NVPF symmetric cell. The electrochemical impedance spectroscopy (EIS) carried out during cycling showed increases in bulk resistance, solid electrolyte interphase (SEI) resistance, and charge transfer resistance with the number of cycles, explaining the origin of capacity fade in the NVPF symmetric cell. Finally, the postmortem analysis of the symmetric cell after 1000 cycles at a 1 C rate indicated that the intercalation/de-intercalation of sodium into/from the host structure occurred without any major structural destabilization in both the cathode and anode. However, there was slight distortion in the cathode structure observed, which resulted in capacity loss of the symmetric cell. The promising electrochemical performance of NVPF in the symmetric cell makes it attractive for developing long-life and cost-effective batteries.

Agar Acts as Cathode Microskin to Extend the Cycling Life of Zn//α-MnO2 Batteries.

The Zn/MnO2 battery is a promising energy storage system, owing to its high energy density and low cost, but due to the dissolution of the cathode material, its cycle life is limited, which hinders its further development. Therefore, we introduced agar as a microskin for a MnO2 electrode to improve its cycle life and optimize other electrochemical properties. The results showed that the agar-coating layer improved the wettability of the electrode material, thereby promoting the diffusion rate of Zn2+ and reducing the interface impedance of the MnO2 electrode material. Therefore, the Zn/MnO2 battery exhibited outstanding rate performance. In addition, the agar-coating layer promoted the reversibility of the MnO2/Mn2+ reaction and acted as a colloidal physical barrier to prevent the dissolution of Mn2+, so that the Zn/MnO2 battery had a high specific capacity and exhibited excellent cycle stability.

Composite Polybenzimidazole Membrane with High Capacity Retention for Vanadium Redox Flow Batteries.

Currently, energy storage technologies are becoming essential in the transition of replacing fossil fuels with more renewable electricity production means. Among storage technologies, redox flow batteries (RFBs) can represent a valid option due to their unique characteristic of decoupling energy storage from power output. To push RFBs further into the market, it is essential to include low-cost materials such as new generation membranes with low ohmic resistance, high transport selectivity, and long durability. This work proposes a composite membrane for vanadium RFBs and a method of preparation. The membrane was prepared starting from two polymers, meta-polybenzimidazole (6 µm) and porous polypropylene (30 µm), through a gluing approach by hot-pressing. In a vanadium RFB, the composite membrane exhibited a high energy efficiency (~84%) and discharge capacity (~90%) with a 99% capacity retention over 90 cycles at 120 mA·cm-2, exceeding commercial Nafion® NR212 (~82% efficiency, capacity drop from 90% to 40%) and Fumasep® FAP-450 (~76% efficiency, capacity drop from 80 to 65%).

Ionic and Electronic Conductivities of Lithium Argyrodite Li6PS5Cl Electrolytes Prepared via Wet Milling and Post-Annealing.

Lithium argyrodite Li6PS5Cl powders are synthesized from Li2S, P2S5, and LiCl via wet milling and post-annealing at 500°C for 4 h. Organic solvents such as hexane, heptane, toluene, and xylene are used during the wet milling process. The phase evolution, powder morphology, and electrochemical properties of the wet-milled Li6PS5Cl powders and electrolytes are studied. Compared to dry milling, the processing time is significantly reduced via wet milling. The nature of the solvent does not affect the ionic conductivity significantly; however, the electronic conductivity changes noticeably. The study indicates that xylene and toluene can be used for the wet milling to synthesize Li6PS5Cl electrolyte powder with low electronic and comparable ionic conductivities. The all-solid-state cell with the xylene-processed Li6PS5Cl electrolyte exhibits the highest discharge capacity of 192.4 mAh·g-1 and a Coulombic efficiency of 81.3% for the first discharge cycle.

The Electrochemical Performances of n-Type Extended Lattice Spaced Si Negative Electrodes for Lithium-Ion Batteries.

The electrochemical performances of lithium-ion batteries with different lattice-spacing Si negative electrodes were investigated. To achieve a homogeneous distribution of impurities in the Si anodes, single crystalline Si wafers with As-dopant were ball-milled to form irregular and agglomerated micro-flakes with an average size of ~10 µm. The structural analysis proved that the As-doped Si negative materials retain the increased lattice constant, thus, keep the existence of the residual tensile stress of around 1.7 GPa compared with undoped Si anode. Electrochemical characterization showed that the As-doped Si anodes have lower discharge capacity, but Coulombic efficiency and capacity retention were improved in contrast with those of the undoped one. This improvement of electrochemical characteristics was attributed to the increased potential barrier on the side of Si anodes, inherited from the electronic and mechanical nature of Si materials doped with As. We believe that this study will guide us the way to optimize the electrochemical performances of LIBs with Si-based anodes.

CeF3-Doped Porous Carbon Nanofibers as Sulfur Immobilizers in Cathode Material for High-Performance Lithium-Sulfur Batteries.

In this study, the CeF3-doped porous carbon nanofibers (PCNFs), prepared via electroblown spinning technique and carbonization process, are used as sulfur immobilizers in cathodes for lithium-sulfur (Li-S) batteries for the first time. The cathode composed of CeF3-doped PCNFs, carbon nanotubes (CNTs), and S is successfully prepared through the ball-milling and heating method. The formed porous structure in the PCNFs and CNTs facilitates the construction of highly electrically conductive pathways and effectively alleviates volume changes, which can maintain the stability of the cathode structure and make them in close contact between the electrodes. Meanwhile, the intermediate polysulfide dissolved and lost in the electrolyte can also be suppressed because of the hierarchical porous carbon nanofibers and CeF3. The Li-S battery using the cathode can display excellent electrochemical properties and stable capacity retention, presenting an initial discharge capacity of 1395.0 mAh g-1 and retaining a capacity of 901.2 mAh g-1 after 500 cycles at 0.5C. During the rate capability tests of battery, the discharge capacity of Li-S battery with the electrode slowed down from the discharge capacity of 1284.6 mAh g-1 at 0.5C to 1038.6 mAh g-1 at 1C and 819.3 mAh g-1 at 2C, respectively. It is noteworthy that the battery can still endow an outstanding discharge capacity of 1269.73 mAh g-1 with a high retention of 99.2% when the current density returns to 0.5C.

Facile Synthesis of Boron-Doped rGO as Cathode Material for High Energy Li-O2 Batteries.

To improve the electrochemical performance of the high energy Li-O2 batteries, it is important to design and construct a suitable and effective oxygen-breathing cathode. Herein, a three-dimensional (3D) porous boron-doped reduction graphite oxide (B-rGO) material with a hierarchical structure has been prepared by a facile freeze-drying method. In this design, boric acid as the boron source helps to form the 3D porous structure, owing to its cross-linking and pore-forming function. This architecture facilitates the rapid oxygen diffusion and electrolyte penetration in the electrode. Meanwhile, the boron-oxygen functional groups linking to the carbon surface or edge serve as additional reaction sites to activate the ORR process. It is vital that boron atoms have been doped into the carbon lattices to greatly activate the electrons in the carbon π system, which is beneficial for fast charge under large current densities. Density functional theory calculation demonstrates that B-rGO exhibits much stronger interactions with Li5O6 clusters, so that B-rGO more effectively activates Li-O bonds to decompose Li2O2 during charge than rGO does. With B-rGO as a catalytic substrate, the Li-O2 battery achieves a high discharge capacity and excellent rate capability. Moreover, catalysts could be added into the B-rGO substrate to further lower the overpotential and enhance the cycling performance in future.

A Facile Synthesis of High-Surface-Area Sulfur-Carbon Composites for Li/S Batteries.

Small-grained elemental sulfur is precipitated from sodium thiosulfate (Na2 S2 O3 ) in a carbon-containing oxalic acid (HOOC-COOH) solution through a novel spray precipitation method. Surface area analysis, elemental mapping, and transmission electron micrographs revealed that the spray-precipitated sulfur particles feature 11 times higher surface area compared to conventional precipitated sulfur, with homogeneous distribution in the carbon. Moreover, the scanning electron micrographs show that these high-surface-area sulfur particles are firmly adhered to and covered by carbon. This precipitated S-C composite exhibits high discharge capacity with about 75 % capacity retention. The initial discharge capacity was further improved to 1444 mA h g(-1) by inserting a free-standing single-walled carbon nanotube layer in between the cathode and the separator. Moreover, with the help of the fixed capacity charging technique, 91.6 % capacity retention was achieved.