Cycling Stability Research Articles

A polyolefin separator reinforced inorganic/organic composite electrolyte for quasi-solid-state Lithium-sulfur batteries with high cycle stability and long lifespan

Lithium-sulfur (Li-S) batteries are considered a promising next-generation energy storage system due to the high energy density and the low cost. However, the severe shuttle effect of polysulfide and the security issue caused by organic liquid electrolyte and lithium metal anode have hindered their commercial application. Herein we achieved a polyolefin commercial separator reinforced inorganic/organic composite electrolyte (denoted as Com-LATP) via coating the polypropylene (PP) separator with the composite of polymethyl methacrylate/poly(vinylidene fluoride) (PMMA/PVDF) modified with Li1.3Al0.3Ti1.7(PO4)3 (LATP). The Com-LATP electrolyte (thickness: ∼30 um) exhibits remarkable tensile strength of 103 MPa, an ionic conductivity of 0.47·mS cm-1 with the Li+ transfer number of 0.45, which is beneficial for the uniform Li+ flux and the stable striping and plating of Li metal. The Li symmetrical batteries equipped with this Com-LATP exhibited stable cycling for over 350 h. Meanwhile, the Com-LATP electrolyte with the special dense structure can hinder the polysulfide diffusion. The developed quasi-solid-state lithium-sulfur batteries have demonstrated impressive cycling stability with an initial specific capacity of 1184.8 mA h g-1 at a discharge rate of 0.2 C, maintaining performance over 200 cycles. Additionally, they exhibited outstanding rate capability, retaining a reversible capacity of 710.4 mA h g-1 even at a higher discharge rate of 2 C. This research introduces an innovative structural design approach for high-performance quasi-solid-state Li-S batteries, which holds significant promise for advancing the commercialization of lithium-sulfur battery technology.

Excellent Energy Storage Performance of Multi-Alternating-Layer Structured PMMA/PVDF Dielectric Composite at High-Temperature

Polymer dielectric capacitors have high power density and are an integral component of electronic and power device. Currently, the limited energy density restricts their further application. In this research, a novel method was designed to optimize performance of PMMA/PVDF composite via an alternating stacked multi-layer structure. And, the five-alternating-layer of PVDF-PMMA-PVDF-PMMA-PVDF (F-A-F-A-F) composite has excellent dielectric properties, for instance, a better dielectric constant (4.52@1 kHz) and a low dielectric loss (0.034@1 kHz). The discharge energy density (Ue) of it is significantly larger than that of PMMA and PVDF. Particularly, the Ue of F-A-F-A-F composite is increased by 83.0% (from 4.71 J/cm3 to 8.62 J/cm3) with charging-discharging efficiency of 60% at 80 °C. Moreover, the F-A-F-A-F composite achieves an excellent stability after 40,000 cycles. This composite has a wide range of potential applications in the field of traditional dielectric capacitor due to its good energy storage performance and cycle stability.

Simultaneous structure and surface engineering of metal-organic framework derived LiNi0.5-xFe2xMn1.5-xO4 cathode material for improving high voltage performance of lithium-ion batteries

This study presents a novel material synthesis approach utilizing a terephthalic acid-based metal-organic framework as a precursor and employing an ethanol-assisted hydrothermal treatment to produce high-performance Fe-doped LiNi0.5Mn1.5O4 (LNMO) cathode material. This strategy yields a well-crystallized spinel structure with uniformly distributed transition metal ions. Additionally, the appropriate quantity of Fe dopant can achieve the desired Mn3+/Mn4+ ratio, level of structural disordering, and crystal phase purity for Fe-doped LNMO. The synthesis process also aids in forming an amorphous Li2CO3 surface layer, approximately 1 nm thick, which protects the active material from excessive reaction with electrolyte. The typical Fe-doped LNMO cathode (S-05) exhibits superior performance compared to a commercialized LNMO counterpart. It delivers an initial discharge capacity of 135 mAh g-1 at 1 C with exceptional cycling stability over 500 cycles (capacity retention of 90%) under high voltage (5.0 V vs. Li+/Li). Furthermore, its rate capability significantly improves, with a capacity retention of 85% (5 C/0.2 C). This enhanced performance aligns with evidence of activated Ni2+/Ni3+/Ni4+ redox reactions and suppressed cathode electrolyte interphase resistance, leading to promoted Li+ diffusion. Moreover, it is found the cathode helps alleviate electrolyte degradation at high voltages by inhibiting the formation of singlet oxygen in the electrolyte.

Vacuum assisted desorption of sodium zirconate sorbent for enhancing cyclic stability in pre-combustion CO2 capture

Sodium zirconate (Na2ZrO3) is a promising material for pre-combustion CO2 capture due to its fast sorption kinetics and excellent cyclic stability at high temperatures under ideal condition (desorption in 100% N2). Still, there is a lack of study on the performance of Na2ZrO3 cyclic capture under harsh condition (desorption in high concentration CO2). In this study, Na2ZrO3 was prepared by wet-mixing and heated-drying, and the difference in the cyclic CO2 capture performance of the sample was compared between desorption under harsh condition and vacuum condition. The crystal structure of Na2ZrO3 was identified during the sorption-desorption cycles. The crystal structure was also modeled and simulated to analyze the reason for the superior capture performance from the monoclinic Na2ZrO3. It was found that the special interlocked and multilayered stacked structure of the monoclinic Na2ZrO3 allowed for high reactivity with CO2. It was found that high temperature solely had little help in the desorption of Na2ZrO3 under harsh condition, but vacuum condition promoted desorption of Na2ZrO3 in high fraction CO2, and vacuum desorption at 1000 °C-1050 °C resulted in Na2ZrO3 with both good capture performance and cycling stability. Vacuum desorption led to more complete reversion of Na2ZrO3 to the monoclinic state, benefiting for CO2 capture. This study attempted to simulate the harsh capture environments of real industrial applications and to explore the possibility of Na2ZrO3 as a carbon capture material for pre-combustion capture.

Facile synthesis of Co/Fe bimetallic doped Ni3S2 nanosheets and supercapacitor performance

Ni3S2 is an outstanding electrode material due to its high theoretical specific capacity, however, in practical research, the higher theoretical capacity is difficult to show, and the change of the structure in the cycling process affects the cycling stability, which limits its practical application. To address these issues, this study presents a strategy to synthesize Fe and Co bimetallic doped Ni3S2 nanosheets on nickel foam (NF) surface. This strategy introduces bimetallic atoms quickly and easily while synthesizing nanosheet structures, and the resulting synergistic interactions between the bimetals and the mutual support effect of the nanosheets can effectively enhance electron transfer and improve cycling stability. The electrochemical results show that the Fe and Co-doped sample (Ni3S2-Co/Fe-5) exhibits a specific capacitance of 3351 F·g−1 at 1 A·g−1 in the three-electrode system, which is nearly five times higher than the specific capacity of the undoped Fe and Co-doped sample (Ni3S2), and the capacity retention rate after cycling 5000 cycles at a current density of 10 A·g−1 is 100 %, the prepared sample (Ni3S2-Co/Fe-5) was assembled with activated carbon (AC) to form a hybrid supercapacitor, which could provide a maximum power density of 9818 W·kg−1, a maximum energy density of 66.25 Wh·kg−1, and a capacity retention of 94.5 % after 10,000 cycles, with a capacity loss of only 5.6 %.

Sb-anchoring single-crystal engineering enables ultra-high-Ni layered oxides with high-voltage tolerance and long-cycle stability

Ni-rich layered oxides are promising cathodes for Li-ion batteries, but the inherent structural defects result in severe surface/bulk degradation during long cycling, especially at high cutoff voltage. Herein we propose a Sb-anchoring single-crystalline engineering to enhance the microstructural and electrochemical stability of ultra-high-Ni layered oxides, where the surface-enriched Sb doping inhibits Li-Ni mixing, suppressing the undesired layered to mixed/rock-salt phase transformation; the bulk-doped Sb rivets into Ni sites, reinforcing the bulk phase stability; the single-crystal endows enhanced crack resistance and reduced surface area, preventing surface parasitic reactions and the subsequent proliferation of cathode electrolyte interfaces. In-situ XRD reveals an essential correlation between cycle stability and phase reversibility, whereas Sb doping into both surface and bulk structures showcases a continuous anchoring effect, largely enhancing the phase transformation reversibility. DFT calculations prove a high oxidation tolerance, as Ni2+ diffusion barrier is higher than the pure cathode. A representative Li(Ni0.9Co0.05Mn0.05)0.99Sb0.01O2 cathode exhibits a high-voltage up to 4.6V, and a Li(Ni0.9Co0.05Mn0.05)0.99Sb0.01O2//graphite full-cell demonstrates an ultra-high capacity retention of 93.4% after 1000 cycles at 1C in 3.0−4.2V. This simple and efficient cathode engineering will promote the promising application of Ni-rich layered oxides in high-energy Li-ion batteries.

Advancing energy storage capabilities in 0.7BNST(1-x)-0.3BLMNx lead-free dielectric ceramic materials

Lead-free ferroelectric ceramics with a composition of 0.7(Bi0.5Na0.5)0.7Sr0.3Ti(1-x)O3-0.3Ba0.94La0.04(Mg1/3Nb2/3)xO3 (abbreviated as 0.7BNST(1-x)-0.3BL(MN)x, 0 ≤ x ≤ 0.12) were prepared using solid-phase sintering method, involving co-substituting at A and B sites. High recoverable energy density (Wrec) of 3.54 J/cm3 and energy efficiency (η) 85.49% are achieved at an electric field of 270 kV/cm. Furthermore, these ceramics exhibited excellent temperature and cycle stability at 120 kV/cm (within 25 °C–150 °C, Wrec fluctuation range <14 %; under 1∼106 cycles, the Wrec fluctuation range <5 %). In terms of dielectric performance, they exhibited a high dielectric constant (εr∼4540), an extremely low dielectric loss tanδ of <0.04 (30 °C–300 °C), and good temperature stability with Δε/ε150 °C ≤ ±15 % (−19.5 °C–233.4 °C). During the charging and discharging process, these ceramics demonstrated a high energy density (Wd) of 1.2 J/cm3, a power density (PD) of 61.7 MW/cm3, and an extremely short discharge time (t0.9) of approximately ∼0.11 μs＀ This study has improved the dielectric energy storage performance of BNT-based lead-free piezoelectric ceramics, making them suitable for use in pulse power devices.

Novel carbon nitride for efficient degradation of organic pollutants and value-added recycled plastics: synergistic effects of nitrogen vacancies and Fe

The introduction of nitrogen vacancies (VN) and iron (Fe) single atoms sites significantly enhances the visible light absorption and charge transfer ability of carbon nitride (CN) catalysts. This paper presents the successful synthesis of a VN-rich, Fe single atoms incorporated CN, a catalyst that demonstrates exceptional degradation performance and cycling stability. The 2-mercaptobenzothiazole (MBT) removal rate by 20Fe-CN reached 99.51% within just 11min under visible light, and the catalyst maintained superior photocatalytic performance upon repeated use. Additionally, the 20Fe-CN/Photo/High-temperature system effectively converted polystyrene (PS) to benzoic acid (BA), achieving a BA yield of 19.73% after 48hours. Under visible light irradiation, the VN sites captured electrons and facilitated their rapid transfer to neighboring Fe sites, enhancing the photocatalytic redox processes. This study also identified ·O2- as the primary active species in the photocatalytic process. This research supports the development of diverse single-atom modified carbon nitride photocatalysts, holding significant potential for wastewater treatment and plastic resource recycling, and providing valuable insights for future photocatalysts in environmental remediation.

A novel smart window based on co-crosslinked hydrogel with temperature self-adaptability and anti-freezing functions for building energy saving

Thermochromic smart windows based on hydrogels with adaptive regulation of solar radiation have attracted an increasing attention due to their potential in temperature management. However, hydrogels with extremely high water content may freeze, leading to the risk of transparency reduction and even window breakage in cold environment. In this study, co-crosslinked P(NIPAM-co-AM)@GLY@PVA hydrogel with excellent solar radiation regulation and anti-freezing performance was prepared by introducing antifreeze glycerol (GLY) and polymer polyvinyl alcohol (PVA). By adjusting the amount of GLY, PVA and hydrophilic AM, P(NIPAM-co-AM)@GLY@PVA hydrogel showed a satisfactory thermochromic performance, with a luminous transmittance (Tlum) of 68.05 %, a solar modulation ability (ΔTsol) of 62.11 %, a lower critical solution temperature (LCST) of ∼24 °C and an antifreeze temperature of −15 °C. The thermal management experiments proved that the thermochromic@anti-freezing (TCA) smart window assembled based on P(NIPAM-co-AM)@GLY@PVA hydrogel had an excellent performance in managing indoor temperature and cyclic stability. This work may open a new avenue to solve problems in the application field of hydrogel-based smart windows

Effects of Symmetric and Asymmetric Pre-Compression Combinations on the Mechanical Properties and Fatigue Behavior of ZK60 Magnesium Alloy

Pre-compression modes influence the microstructure of rolled magnesium alloys, thereby enhancing their mechanical and fatigue properties. This study investigates the distribution of dislocations, extension twins, and texture components in rolled ZK60 magnesium alloy sheets subjected to single-pass pre-compression (S-PT3), symmetric pre-compression (S-PT3R3), and asymmetric pre-compression (S-PT3R6). The results indicate that the variation in the orientation of pre-twin textures, leading to differences in the Schmid factor, is the primary cause of the mechanical performance differences observed under different pre-compression modes. In contrast, the hardening effect due to grain refinement is negligible. As the total amount of pre-compression increases, the hardening effect of pre-dislocations becomes more significant. Single-pass pre-compression exhibits a higher fatigue life under large strain amplitudes. Although asymmetric pre-compressed samples show increased overall strength and hardness, their fatigue life and cyclic stability are inferior. During cyclic loading, different pre-compression modes significantly impact the hysteresis curve, deformation mechanisms, stress ratio, and elastic limit amplitude. Symmetric pre-compression samples exhibit superior cyclic stability and fatigue life. Based on different application requirements, suitable pre-compression treatment methods can be selected to optimize the performance of ZK60 magnesium alloys, providing scientific guidance for practical engineering applications.

Effect of Ce-Doping on the Structural, Morphological, and Electrochemical Features of Co3O4 Nanoparticles Synthesized by Solution Combustion Method for Battery-Type Supercapacitors

This study investigates the potential of cerium (Ce) doping to improve the performance of cobalt oxide (Co₃O₄) nanoparticles as battery-type supercapacitor electrodes. Pure Co₃O₄ nanoparticles were synthesized via a solution combustion method and then doped with 2.5% (Ce-Co3O4) and 5% Ce (CeO2-Co3O4). Comprehensive characterization, including X-ray diffraction (XRD), Raman spectroscopy, and field emission scanning electron microscopy (FESEM), was used to analyze the impact of Ce doping on the material properties. XRD analysis confirmed the successful incorporation of Ce into the Co₃O₄ structure, with distinct CeO2 phases forming at higher doping levels. Ce doping resulted in decreased crystallite size and peak intensity, indicating reduced crystallinity and increased defect concentration. Raman spectroscopy corroborated these findings, showing a redshift that suggests weakened metal-oxygen bonds and smaller grain sizes due to Ce³⁺ incorporation. FESEM images demonstrated that Ce doping effectively reduced nanoparticle agglomeration, with 2.5% doping leading to smaller particles and 5% doping promoting a 2D flake-like morphology with increased porosity. Nitrogen adsorption-desorption measurements revealed a significant increase in surface area and pore volume for CeO2-Co₃O₄, facilitating improved electrolyte diffusion and reduced resistance, thereby enhancing electrochemical performance. Evaluation of the electrochemical properties of undoped and Ce-doped Co₃O₄ materials revealed a battery-like response in a three-electrode configuration. Notably, the CeO2-Co3O4 exhibited a superior specific capacity of 603.3 C g-1 at a current density of 1 A g-1, significantly exceeding the values of 368.5 C g-1 and 127.1 C g-1 achieved by Ce-Co3O4 and undoped Co3O4, respectively. Furthermore, the CeO2-doped Co3O4 demonstrated exceptional cyclic stability, retaining 87% of its initial capacity after undergoing 5000 charge-discharge cycles at a high current density of 10 A g-1. These results suggest that Ce doping is a promising strategy for optimizing Co₃O₄-based battery-type electrode materials, potentially leading to the development of high-performance and cost-effective energy storage systems.

Hydrothermal-calcination synthesis of lithium orthosilicate microspheres for high-temperature CO2 capture

In recent years, the Li4SiO4 adsorbent has become a promising candidate for high-temperature CO2 capture. The fabrication of micro-structured Li4SiO4 could enhance the capture performance effectively. However, there exists a conflict between the purity and the morphology of prepared micro-structured Li4SiO4. This study proposed a novel hydrothermal-calcination method, which could produce Li4SiO4 microspheres with great morphology and relatively high purity. The physicochemical properties, CO2 capture performance and forming mechanisms of Li4SiO4 microspheres are evaluated and investigated systematically. It is found that the hydrothermal process could fabricate micro-spherical LiOH@Li2SiO3 precursor, which was further converted to Li4SiO4 microspheres during the subsequent calcination process. The LiOH@Li2SiO3 precursor could not only maintain the microstructure but also reduce the Li4SiO4 generation temperature, thus improving the morphology as well as the purity of obtained Li4SiO4 microspheres. As a result, the adsorbents could reach a CO2 capture capacity of 0.167–0.222 g/g within 30 min's adsorption under 15 vol.% CO2, and their cyclic stability are diverse depending on the used calcination temperatures. The hydrothermal-calcination contributes to the future preparation of high-performance Li4SiO4-based CO2 adsorbents.

Impact of Climate Change on Spatiotemporal Patterns of Snow Hydrology: Conceptual Frameworks, Machine learning versus Nested Model

Snow accumulation in mountainous watersheds plays a paramount role in the hydrological cycle and environmental stability. In the current research, three different snow modeling approaches including conceptual models, Random Forest (RF) and their nested (Nested-RF) model have been implemented to project climate change. Also, three distinct calibration scenarios employing Snow Cover Area (SCA) and Snow Water Equivalent (SWE) have been used. These scenarios involve using SCA and SWE data individually or combined to calibrate both conceptual snowpack models and machine learning methods. Considering comparative analysis in the mountainous and complex topographic area of Tashk-Bakhtegan watershed as a case study, the Guo model (calibrated using both SCA and SWE data) achieves the highest prediction accuracy in predicting SCA/SWE using conceptual method. Considering various statistics, RF using the same calibration scenario demonstrates high accuracy in estimating SWE and shows promising results in detecting SCA. Considering the feature importance analysis and statistics of the RF and Nested-RF models indicate that the feeding conceptual outputs as extra information into the Nested-RF had minimal influence and even slightly reduced accuracy. Future projections using RF indicate significant reductions in mean annually SCA/SWE, especially under SSP8.5, with a 28.4% decrease in SCA and a reduction in SWE to 13.62 mm from a historical baseline of 19.4 mm. Lower emission scenarios (SSP2.6 and SSP4.5) show less drastic declines. While minor differences were observed between the best conceptual model and the RF approach in capturing spatiotemporal and annual snow patterns, these discrepancies did not reach statistical significance.

Activation of Algicidal Bacteria and Nitrogen-Phosphorus Removal Bacteria During Controlling Cyanobacteria Bloom in Taihu Lake by Artemisinin Algaecide

Cyanobacterial harmful algal blooms (CyanoHABs) in Taihu Lake pose a persistent environmental challenge. This study investigated the inhibitory effects of artemisinin algaecide (AMA) on cyanobacteria in Taihu Lake and assessed its impact on nutrients, as well as the structures of particle-attached (PA) and free-living (FL) bacterial communities and potential ecological mechanisms. The results indicated that A-3 (0.8g artemisinin/L) effectively inhibited CyanoHABs (inhibition rate = 93%) and significantly increased the alpha diversity of PA and FL bacterial communities during the stationary phase， thereby promoting the proliferation of algicidal bacteria (AB) (e.g., Acinetobacter, Stenotrophomonas, and Exiguobacterium) and heterotrophic nitrification-aerobic denitrification (HN-AD) bacteria (e.g., Acinetobacter, Stenotrophomonas, and Bacillus) through the utilization of dissolved organic carbon (DOC) from the dead cyanobacteria. This proliferation enhanced nitrogen metabolism and increased the abundance of nitrogen-cycling functional genes, improving nutrient cycling and enhancing system stability. The increased abundance of AB continuously suppressed cyanobacteria, while the proliferation of HN-AD bacteria removed nitrogen and phosphorus from the water, thus limiting nutrients available for cyanobacterial growth. Our findings demonstrate that AMA effectively inhibits CyanoHABs and prevents secondary blooms, providing a scientific foundation for the widespread application in cyanobacterial management, enhancing the effectiveness and sustainability of CyanoHAB control efforts.

SnS2-supported MAPbI3 composites for effective photocatalytic hydrogen evolution

Metal halide perovskites have demonstrated encouraging photocatalytic potential due to their favorable photoelectric properties. However, severe carrier recombination greatly affects their catalytic performance. Here, we introduced cocatalyst SnS2 to synthesize novel SnS2/MAPbI3 composites via the electrostatic coupling method, which presented excellent hydrogen production performance. The hydrogen production rate of 5 % SnS2/MAPbI3 (5 wt% SnS2/MAPbI3) reached 445.96 μmol·g−1·h−1, about 325-fold increase compared to pure MAPbI3 (1.37 μmol·g−1·h−1). The 16 h cycle stability test proved its stability and effectiveness. Detailed experimental characterizations and analysis indicate that the cocatalyst SnS2 reduces the surface overpotential and facilitates electron transport and efficiently separates photogenerated charge carriers. This work provides new insights into effective photocatalysts based on MAPbI3.

MnOOH nanorods decorated with CeO2 nanoparticles as advanced electrode for high-performance supercapacitor

The development of novel composite electrode materials is essential to fabricating supercapacitors with high specific capacitance and good stability. In this study, MnOOH nanorods adorned with CeO2 (CeMn composites) have been satisfactorily synthesized through in-situ growth of tiny CeO2 nanoparticles using hydrothermal treatment. SEM images revealed that the granular CeO2 particles are adhered to the surfaces of nanorod-shaped MnOOH. XRD analysis confirmed the CeMn composites maintain the crystal structure of MnOOH and CeO2 with high purity. The EDS elemental mapping images demonstrated that Mn, O, and Ce elements are homogenously dispersion distributed in the CeMn composites. The supercapacitive performance of the MnOOH and CeMn composites pasted onto the Ni foam was evaluated determined through electrochemical measurements. The Ce0.05Mn1 (Ce/Mn molar ratio of 0.05/1) as a supercapacitor electrode exhibited an excellent specific capacitance of 857.62 F/g at 1 A/g, which is higher than the values for the MnOOH. Moreover, the prepared Ce0.05Mn1 still could retain good cycling stability over 3000 charge/discharge cycles. This study presents a feasible route to develop high-performing supercapacitor electrode materials.

Polyaniline@MoS2: An organic and inorganic hybrid framework for asymmetric supercapacitor applications

The polyaniline and MoS2-based organic and inorganic hybrid composite have been synthesized by varying MoS2 concentrations ranging from 1 to 10 wt% and their charge storage performances were analyzed in a three-electrode and in asymmetric cell configuration to understand their electrochemical characteristics. The electrochemical characteristics of the as-prepared electrodes such as cyclic voltammetry, galvanostatic charge-discharge, and electrochemical impedance spectroscopy were studied in 1 M H2SO4 electrolyte. Among the prepared compositions PANI@MoS2 (5 wt%) electrode showed a high specific capacity of 148.6 F g−1 at 0.5 A g−1 among the prepared compositions. Further, the asymmetric hybrid pouch cell was fabricated where PANI@MoS2 and activated carbon were used as a positive and negative electrode, respectively. The 2 × 2 cm2 asymmetric cell (AC||PANI@MoS2(5 wt%) delivered a specific energy of 32 Wh kg−1 at a specific power of 3.2 kW kg−1 in the PVA-H2SO4 hydrogel electrolyte. This specific energy is two-fold higher than the AC||PANI asymmetric cell where the specific energy and specific power are about 18.66 Wh kg−1 and 3.2 kW kg−1, respectively. The cycle stability of the AC||PANI@MoS2 (5 wt%) was also performed at 2 A g−1 and the cell showed capacitance retention of about 99.27% after 13,000 cycles. The cell performances at different bending angles were analyzed to ensure the flexible nature of the pouch cell. Thus, the proposed organic and inorganic hybrid composite electrode is believed to be a potential electrode material for supercapacitor application in an acidic electrolyte medium.

Investigation of the effects of tri-ammonium citrate electrolyte additive for lead-acid battery using lead foil as negative grid

This study aims to create a lead foil anode for lead-acid batteries with high specific energy, lightweight, and corrosion-resistant. The research also discovered that incorporating tri-ammonium citrate (AC) into the electrolyte significantly enhances the cycling performance of the pure lead level foil negative electrode under high-rate-partial-state-of-charge (HRPSoC) conditions. This addition also increases the specific capacity at high rates, resulting in a 2.3-fold improvement in HRPSoC cycling performance at a 1C rate and a 52 % increase in discharged capacity at a 4C rate, compared to the control blank plate without AC. Through X-ray diffraction (XRD), scanning electron microscope (SEM), and other material characterization methods, as well as electrochemical tests, it is proved that AC improves the morphology of lead sulfate into a lamellar stacked structure. It can also effectively refine lead sulfate grains and inhibit sulfation. In addition, pure lead foil batteries exhibit superior capacity cycle stability at a high multiplication rate compared to grid lead-based alloy batteries. Pure lead foil batteries also have a significantly longer cycle life, with a 65 % increase in discharge-specific capacity at a 4C multiplication rate and a 2.2 times and 1.8 times increase in cycle life at 1C and 2C multiplication rates, respectively.

Embedding Pt in Ni-MOF/CdS organic-inorganic hybrid materials as electron channel to promote photogenerated carrier separation for enhanced photocatalytic hydrogen evolution under visible light

CdS exhibits a high photogenerated carrier yield, yet it is susceptible to photocorrosion due to the limited number of active sites. Ni-MOF boasts a considerable specific surface area and a plethora of active sites, yet it displays a low photogenerated carrier yield and suboptimal conductivity. In this study, the incorporation of Pt into a Ni-MOF/Pt/CdS hybrid material served as an electron transport channel, effectively addressing the limitations of CdS, Ni-MOF, and electrical conductivity. The results of electrochemical tests demonstrate that the electron transport and separation efficiency of the hybridised material is noteworthy. Following the performance test, the optimal visible photocatalytic hydrogen evolution rate of the Ni-MOF/Pt/CdS hybrid material was found to be 14.1 mmol h−1g−1, representing a significant enhancement of approximately 61.3 times compared to that of pure CdS. Furthermore, XPS analysis indicates the presence of Pt-S bonds, which effectively inhibit the oxidation of S2− to S on the CdS surface, thus alleviating the photocorrosion phenomenon and enhancing the cycling stability. This level of stability is maintained at 92.6 % after five cycles. This work offers a novel approach to addressing the limitations of inorganic catalysts, including the scarcity of active sites and the low photogenerated carrier yield, as well as the poor conductivity observed in organic catalysts.

Three-dimensional allium flower-like iron-cobalt sulfide nanomaterials for high-performance supercapacitors

Supercapacitors with their improved performance in high energy density and long-term cycling stability have been the growing trend in recent years for fulfilling the demand of efficient energy storage systems. Herein, we report morphology-controlled three-dimensional (3D) Allium flower-like bimetallic iron-cobalt sulfide (3D-FeCoS AF) nanomaterials on nickel foam (NF) electrodes using a single-step electrochemical deposition strategy. The self-standing bimetallic 3D-FeCoS AF nanostructures show good performance towards the supercapacitance applications. The 3D-FeCoS AF nanostructures delivered a specific capacitance of ∼375.7 F g−1 at a current density of 1.0 A/g. The possible electron cloud delocalization among the FeS nanostructures through d-bands leads to the lower charge transport resistance at the 3D-FeCoS AF electrode–electrolyte interfaces and improved conductivity. The 3D-FeCoS AF electrode demonstrated excellent specific capacity and rate performance in a 2.0 M KOH electrolyte. Owing to their enormous electrochemical active surface area (ECSA) and distinctive 3D nanosheet morphology, the present 3D-FeCoS electrode holds great potential for the fabrication of additional transition metal sulfide materials for excellent supercapacitor performances. The findings of this study suggest promising prospects for the utilization of these materials in practical supercapacitance applications.