Long Cycle Life Research Articles

Cubic hollow porous carbon with defective-edge Fe-N4 single-atom sites for high-performance Zn-air batteries

Regulating the local coordination of Fe active center can further improve the oxygen reduction reaction (ORR) performance of Fe-N-C catalyst to meet the practical application requirements of zinc-air batteries (ZABs). Herein, carbon vacancies modified hollow porous catalysts (C-FeZ8@PDA-950) are constructed by microenvironment modulation, achieving the efficient utilization of active sites and optimization of electronic structure. Density functional theory (DFT) calculations confirm that the defective-edge Fe-N4 sites can weaken the adsorption free energy of OH*, and hinder the dissolution of Fe center, significantly accelerating the ORR process for ZABs. The rechargeable liquid ZABs equipped with C-FeZ8@PDA-950 display high specific capacity (819.95 mAh gZn−1) and excellent long-cycling life (over 500 h). Furthermore, the relevant flexible all-solid-state ZABs also display outstanding folding performance under various bending angles. This work will provide insights into optimizing the electronic structure to improve electrocatalytic performance in the energy conversion and storage area.

Preparation of leaf protoplasts from Populus (Populus × xiaohei T. S. Hwang et Liang) and establishment of transient expression system

Poplar, as a typical woody plant, is an ideal raw material for the production of lignocellulose biofuel. However, the longer life cycle is not conducive to the rapid identification of poplar genes. At present, protoplasts have been used for gene function identification and high-throughput analysis in many model plants. In this paper, a simplified and efficient protoplast isolation and transient expression system of Populus (Populus × xiaohei T. S. Hwang et Liang) is described. Firstly, we proposed an efficient enzyme hydrolysis method for isolating protoplasts from leaves of Populus × xiaohei. Secondly, we optimized the conditions of protoplast transformation mediated by PEG, and established an efficient transient expression system of protoplasts of Populus × xiaohei. Finally, the subcellular localization of three identified Dof transcription factors (PnDof19, PnDof20 and PnDof30) was also observed in the nucleus by using this scheme, which proved that the method was feasible. In general, this efficient method of protoplast isolation and transformation can be used for the study of protein subcellular localization and can be applied to other fields of molecular biology, such as protein interaction, gene activation and so on.

IoT-Based Smart Energy Management in Hybrid Electric Vehicle Using Driving Pattern

Driving patterns involve multiple starts, stops, and goes, requiring both average and momentary demands on power. Batteries function better for the average power demand. An ultracapacitor is used as an auxiliary system with a longer life cycle and higher power density for the vehicle’s momentary power needs. The challenging part of hybridization is smart energy management among the sources. An energy management control strategy decides the energy share among the ESSs. Most of the researchers used standard driving patterns for analyzing vehicle performance. However, a real-time driving pattern is needed to investigate the vehicle’s performance. An IoT-based smart decision-making module can better regulate the energy across the multisource based on sensor unit data about vehicle driving speed. The experimental findings illustrate the effect of the suggested smart energy management control on the hybridization of ESSs to split the power among ESSs to meet the demand for power, maintain the charges in ESSs, and extend the lifespan of the battery. Based on the calculations, the LM approach has a minimal MAD of 0.046781 for training data and 0.043859 for testing data. It has been said that the LM algorithm has the lowest MSE, with values of 0.006397 and 0.005781 for training and testing, respectively. Even in RMSE, the training and testing values of 0.079355 and 0.075893 for the LM Algorithm are the lowest. When the LM algorithm is being trained, its MAPE score is 0.022489, but when it is being tested, it is 0.004846.

An approach to predicting corrosion fatigue for marine applications

Corrosion fatigue is one of the main failure mechanisms of components working in corrosive environments. As a result, the assessment of this phenomenon and taking it into account is of paramount importance in designing such components and particularly in the marine sector where the structural elements are generally designed to have longer life cycles. However, being highly time-demanding due to requiring to be done slowly, conducting corrosion fatigue tests is a serious challenge in marine structures. In this study, at first, the performance of two available methods for accelerating corrosion fatigue tests (using pre-corroded specimens as well as artificially-pitted ones) were compared for a steel with offshore applications. The idea here was to find a way to round out the obligation for conducting the long corrosion fatigue experimental tests with low frequencies. Moreover, extensive finite element (FE) studies have been carried out to predict corrosion fatigue life without the necessity to conduct corrosion fatigue tests and just based on the data obtained from fatigue S-N curves. The numerical and experimental results were in good agreement which means that FE models can effectively be used as a reliable tool to reduce the need for conducting long corrosion fatigue tests.

Dual-atoms iron sites boost the kinetics of reversible conversion of polysulfide for high-performance lithium-sulfur batteries

Atomically dispersed metal catalysts have offered significant potential for accelerating sluggish kinetics of lithium polysulfides conversion and inhibiting the shuttle effect, so as to achieve the long-life cycle and high-rate performance of lithium sulfur batteries. However, the end-on adsorption structure between single metal site and polysulfide limits the adsorption capacity and catalytic activity of single atom catalysts. Here, we construct dual-atoms iron sites on nitrogen doped graphene to serve as highly efficient catalyst for lithium sulfur batteries. As expected, the dual-atoms sites can firmly bind polysulfides by forming double Fe-S bonds between polysulfides and the two adjacent iron atoms. Such double-bond adsorption structure is also favorable for electron transfer and polysulfides activation, resulting in reducing the energy barrier and accelerating the reaction kinetics. As a result, the as-obtained dual-atoms iron catalyst can effectively alleviate the shuttle effect and improve the utilization of active sulfur, thus the batteries present high initial capacity of 1615 mAh g−1 at 0.05 C and long-cycle life with a decay rate per cycle as low as 0.015% at 2C over 1000 cycles.

2D Amorphous Iron Selenide Sulfide Nanosheets for Stable and Rapid Sodium-Ion Storage.

Sodium ion batteries (SIBs) suffer from large electrode volume change and sluggish redox kinetics for the relatively large ionic radius of sodium ions, raising a significant challenge to improve their long-term cyclability and rate capacity. Here, it is proposed to apply 2D amorphous iron selenide sulfide nanosheets (a-FeSeS NSs) as an anode material for SIBs and demonstrate that they exhibit remarkable rate capability of 528.7 mAh g-1 at 1 A g-1 and long-life cycle (10000 cycles) performance (300.4 mAh g-1 ). This performance is much more superior to that of the previously reported Fe-based anode materials, which is attributed to their amorphous structure that alleviates volume expansion of electrode, 2D nature that facilitates electrons/ions transfer, and the S/Se double anions that offer more reaction sites and stabilize the amorphous structure. Such a 2D amorphous strategy provides a fertile platform for structural engineering of other electrode materials, making a more secure energy prospect closer to a reality.

Design of novel thermal management system for Li-ion battery module using metal matrix based passive cooling method

Reliable, efficient and safe energy storage is important for electric vehicles and renewable energy storage of power grid. Lithium-ion battery is preferred as energy storage device due to its higher energy density, low self-discharge and longer cycle life. Lithium-ion cells generate heat during high discharge rates and harsh ambient temperature operation, which raises cell temperature and impacts its performance. Therefore, an efficient thermal management system (TMS) is necessary to alleviate thermal issues during charge/discharge process. A combination of phase change material (PCM) with high conductive plate metal matrix is proposed to eliminate the limitation on the heat transfer characteristics of air-cooled systems. To analyze the thermal and electrochemical behavior of a Lithium-ion cell, a detailed CFD simulation with empirical NTGK electro-chemical model is used. The model is first validated with available experimental data and the analysis is then extended to predict thermal response of individual cell of 3s3p module under natural convection boundary conditions. Poor heat transfer capability associated with natural convection at elevated temperature and discharge rate causes the cell maximum temperature (Tmax) and uniformity (ΔT) to be higher than acceptable values of 45 °C and 3 °C respectively. A thermal management system based on passive cooling using PCM is proposed and analyzed using CFD model by first validating the PCM melting behavior under uniform heating. The model is then extended to analyze the impact of PCM on cell temperature rise at different discharge rates of 8 A - 25 A (≈1C - 3.2C) and various operating temperatures of 25°C to 35°C. Low thermal conductivity of PCM limits heat dissipation which leads to higher temperature gradient. A novel TMS based on plate metal matrix structure enclosing PCM is proposed to enhance heat conduction across PCM and increase heat dissipation to maintain battery module under safe operating temperature limits. This approach has brought down the module maximum temperature to 44.1 °C and temperature difference to 1.6 °C during operation at 25 A (3.2C) and 35 °C. Hence, PCM with high latent heat and low thermal conductivity could be used with high conductivity plate metal matrix to improve cell performance by keeping the cell temperature at required range.

Metal-organic framework derived S-doped anatase TiO2@C to store Na+ with high-rate and long-cycle life

The design of a reasonable structure and component regulation are valid methods for enhancing the electrochemical properties of TiO2, which serves as prominent anode in sodium-ion batteries with exceptional structural stability. Herein, the carbon-coated anatase TiO2 doped with S (S-TiO2 @C) was synthesized via a facile metal-organic framework-assisted approach. The S atoms partially substitute oxygen atoms in the lattice, thereby enhancing the capacitive behavior, facilitating charge transfer kinetics, and augmenting the diffusion coefficient of Na+. With exceptionally high porosity and substantial carbon content, the caky S-TiO2 @C electrode manifests superior rate capability of 167.7 mAh g−1 at 5.0 A g−1 and long-cycle life of 239.0 mAh g−1 at 2.0 A g−1 over 4000 cycles. It is foreseeable that the strategy of anionic doping and carbon coating on the metal oxide with porous structure to optimize the sodium storage capability of the electrode will be applied in the future.

Electrospun Carbon/MXenes Nanofiber Composites for Electrochemical Capacitors

Herein, carbon nanofiber composites derived from polyacrylonitrile/MXene (PAN) using electrospinning technique are proposed as electrode for supercapacitors. Carbon/MXene composite nanofibers were successfully prepared at different MXene contents of 0, 4, 8, and 12 wt. %. Raman spectra displayed rising IG/ID ratio with increase MXene content. XRD results confirmed the embed MXene merged with carbon amorphous. The thermal stability of composite fibers was decreased with adding MXene. Carbon/MXene at 8 wt. % revealed the highest electrochemical supercapacitor of 155.25 F g-1 at 1.0 A g-1 with 100% capacitance retention after 10,000 cycles. Thus, PANMX8 has great potential for supercapacitor application with long-life cycles and fast-charging ability.

Development of chitosan base graphene oxide/ WO3 hybrid composite for supercapacitor application

The use of non-renewable energy has brought to serious environmental problems for the planet. The amount of greenhouse gases rose immediately as the combustion of fossil fuels increased. As a result, sea levels are steadily rising and the Earth is becoming warmer. Research on renewable energy sources has been done extensively to provide a solution. However, in order to maximise energy utilisation, renewable energy needs an energy storage system, such as a super capacitor. For the development of sustainable supercapacitors for future energy systems, electrode material is a prospective target. The formation of desired electrode material is essential in order to fabricate supercapacitor with higher power density and longer life cycle than secondary batteries in electronic application. In this study, chitosan (CS) was isolated from crab shells, and graphene oxide (GO) was synthesized using a modified Hummers' process, followed by a chemical reduction approach. Based on the results, the synthesized GO exhibited higher capacitance as compared to GO that synthesized through single-step modified Hummers’ method. Continuous efforts have been exerted to further improve the electrochemical performance of GO/WO3 nanocomposite by incorporating an optimum content of WO3. In this manner, comprehensive investigations on different parameters, such as loadings of ammonium paratungstate (APT), hydrothermal temperature and reaction time were conducted in order to study the formation of GO/WO3 nanocomposite. WO3 and GO/WO3 nanocomposite were successfully synthesized through a simple hydrothermal method.

In-situ polymerized gel polymer electrolytes for stable solid-state lithium batteries with long-cycle life

The practical application of high energy density lithium batteries is significantly limited by serious safety concerns and chemical instability of traditional organic liquid electrolytes. In this work, polyethylene glycol (PEG) based gel polymer electrolyte (GPE) supported by polyethylene (PE) separator is proposed by in-situ polymerization. The obtained GPE with 50% liquid electrolyte (LE) exhibits an ionic conductivity of 2.22 × 10−4 S cm−1 at 30 °C, a wide electrochemical stability window up to 4.7 V and high lithium ion transference number of 0.502. Furthermore, the GPE displays good interfacial compatibility with lithium anode and the Li//Li symmetric battery with PE supported GPE can cycle stably for 2800 h. In addition, the LiFePO4//Li solid state batteries show outstanding charging/discharging performances at both 30 °C and 60 °C. Particularly, the battery can stable cycle over 1000 cycles at 1 C under 30 °C with capacity retention of 83.36%; meanwhile, it shows a high initial reversible capacity of 149.8 mAh g−1 with excellent cycling stability over 200 cycles at 1 C under 60 °C. This work provides an in-situ polymerized GPE and its promising potential application in lithium metal batteries with a long-cycle life.

Applications of Polymer Electrolytes in Lithium-Ion Batteries: A Review.

Polymer electrolytes, a type of electrolyte used in lithium-ion batteries, combine polymers and ionic salts. Their integration into lithium-ion batteries has resulted in significant advancements in battery technology, including improved safety, increased capacity, and longer cycle life. This review summarizes the mechanisms governing ion transport mechanism, fundamental characteristics, and preparation methods of different types of polymer electrolytes, including solid polymer electrolytes and gel polymer electrolytes. Furthermore, this work explores recent advancements in non-aqueous Li-based battery systems, where polymer electrolytes lead to inherent performance improvements. These battery systems encompass Li-ion polymer batteries, Li-ion solid-state batteries, Li-air batteries, Li-metal batteries, and Li-sulfur batteries. Notably, the advantages of polymer electrolytes extend beyond enhancing safety. This review also highlights the remaining challenges and provides future perspectives, aiming to propose strategies for developing novel polymer electrolytes for high-performance Li-based batteries.

Microplastics evidence in yolk and liver of loggerhead sea turtles (Caretta caretta), a pilot study.

The potential toxicity of microplastics is a growing concern for the scientific community. The loggerhead sea turtle (Caretta caretta) is particularly inclined to accidently ingest plastic and microplastic due to its long-life cycle features. The possible transfer of microplastics from the female to the eggs should be investigated.The present study investigated the presence of microplastics in yolk and liver samples evaluating the number of melanomacrophages in the hepatic tissue as a possible biomarker of microplastics impact on the embryonic health status. The biometric parameters and liver histological analysis of 27 and 48 embryos (from two different nests respectively) at the 30 stage of development were analyzed. Raman Microspectroscopy was performed to identify the microplastics after alkaline digestion (10% KOH) of yolk and portion of liver from 5 embryos at the 30 developmental stage per nest. Microplastics were found in yolk and liver of loggerhead sea turtles at late embryonic stage for the first time. All microplastics were smaller than 5 μm and were made of polymers and colors suggesting their diverse origins. A total number of 21 microplastics, with dimensions lower than 5 μm, were found between the two nests (11 and 10 microplastics respectively). Only two shape categories were identified: spheres and fragments. The most frequent polymers observed were polyethylene, polyvinyl chloride and acrylonitrile butadiene styrene (31.5%, 21.1% and 15.8% respectively). Despite the eggs showing a higher number of microplastics in yolk samples than liver (15 and 6 microplastics in yolk and liver respectively), a positive correlation was observed only between the number of melanomacrophages (r = 0.863 p < 0.001) and microplastics in the liver. This result may suggest that microplastics could exert some effects on the hepatic tissues. Future studies should investigate this aspect and the possible relation between microplastics and other stress biomarkers.

In-situ constructing hetero-structured Mo2C-Mo2N embedded in carbon nanosheet as an efficient separator modifier for high-performance lithium-sulfur batteries

Lithium-sulfur batteries (LSBs) are promising electrochemical energy storage devices. However, the shuttle effects and slow conversion kinetics of lithium polysulfides (LiPSs) still impede the practical application of LSBs. Herein, with the assistance of g-C3N4, a hetero-structured Mo2C-Mo2N embedded in the nitrogen-doped carbon sheets composite (Mo2C-Mo2N/C) is facilely in-situ synthesized. The g-C3N4 not only acts as the nitriding reagent for the heterostructure formation, but also is the structure-directing reagent for the formation of two-dimensional structures. More interestingly, Mo2C-Mo2N/C is also employed as a modifier of separators for LSBs. As evidenced experimentally and theoretically, the hetero-structured Mo2C-Mo2N exhibits a strong adsorption ability to LiPSs and concurrently offers a built-in electric field inside the heterostructure that ensures the fast conversion of LiPSs, thus significantly suppressing the shuttle effect and accelerating the electrochemical kinetics of LSBs. Therefore, the prepared LSBs with the Mo2C-Mo2N/C modified separator deliver a discharge specific capacity of 1404 mAh/g at 0.1 C and 660 mAh/g at 4 C, and achieve 1000 stable cycles at 1 C, with a capacity decay rate of only 0.028% per cycle. This study not only provides an efficient strategy for synthesizing hetero-structured materials but also sheds new light on the design of functional separators for high-performance and long-life cycle LSBs.

Stable and long-life Zn anode enabled by an ion-conductive copolymer coating for rechargeable aqueous batteries

The Zn metal anode endows aqueous zinc-ion batteries (ZIBs) with merits in terms of low cost, high safety, and bivalent ions as charge carriers. Yet the current ZIB technology is immature due to some issues arising from the Zn anode, including the dendrite growth, formation of compound byproducts, and hydrogen gas evolution. Here, a nanoporous and ion-conductive polyvinylidene fluoride-hexafluoro propylene copolymer containing zinc trifluoromethanesulfonate (Zn2+-PVDF-HFP coating) is applied onto the Zn foil to improve its anode performance. The Zn anode covered with Zn2+-containing PVDF-HFP coating (Zn@Zn2+-PVDF-HEP) shows good anti-corrosion performance and much longer cycle life, compared to the bare Zn anode. Also, the byproduct growth and hydrogen gas evolution can be efficiently suppressed due to the Zn2+-conductive copolymer coating. For symmetric cells using Zn@Zn2+-PVDF-HFP, a long lifespan of 2200 cycles is achieved when tested at 1 mA cm−2 and 1 mAh cm−2. Even cycled at 10 mA cm−2 and 5 mAh cm−2, this cell can sustain for over 1800 h. The efficacies of Zn2+-PVDF-HFP coating in prolonging cycle life and enhancing areal capacity of the Zn anode are further verified in MnO2- or V2O5-based full cells, for which the mechanisms are discussed in detail.

Stress Relief in Metal Anodes: Mechanisms and Applications

AbstractMetal anodes (lithium/sodium/zinc) are recognized as the most promising choice for rechargeable batteries due to their high theoretical capacity and low electrochemical redox potential. Unfortunately, metal anodes face serious metal dendrite problems, hindering their practical applications. Recent research has shown that metal dendrites can also be caused by high levels of stress generated during the metal deposition process. To address this issue, an alternative strategy based on stress relief is proposed to inhibit the growth of metal dendrites. Herein, this work aims to investigate the mechanism of stress generation and evolution within metal anodes. In addition, this work explores the utilization of stress to induce metal nucleation. This work further discuss the various experimental techniques used to study stress release in metal dendrites and review recent research findings on stress relief in metal dendrites within metal anodes. Specifically, this work examines how microstructure and processing conditions affect stress release and discuss potential strategies for improving the efficiency of stress relief strategies in metal dendrites. As a result, a deeper understanding of stress release in metal dendrites can lead to the development of rechargeable batteries with superior performance, longer cycle life, as well as enhanced safety for practical applications in various fields.

3D heterostructure constructed by few-layer 1T MoS2 and MXene under high electrostatic fields for high-performance supercapacitors

Electrostatic spray deposition (ESD) is a promising technique for preparing high-quality heterostructure materials to achieve high electrochemical performance. Moreover, the materials obtained by ESD possesses well-dispersed, bonder-free and easy-control advantages. Herein, we firstly report that 1T MoS2/Ti3C2Tx heterostructure material is successfully constructed by few-layer 1T MoS2 and Ti3C2Tx MXene through ESD. The construction of heterostructure by high electrostatic fields is able to solve problem of agglomeration of layered materials, improve conductivity and stabilize 1T MoS2 to realize outstanding electrochemical performance of supercapacitor. As expected, the binder-free 1T MoS2/Ti3C2Tx heterostructure displays an excellent specific capacitance (1198 mF cm−2 at 3 mA cm−2), a high rate performance (45% as current density from 3 to 20 mA cm−2) and long-cycle life (73.8% capacity retention after 7000 cycles at 20 mA cm−2). More interestingly, a simple and efficient route to prepare 2D/2D heterostructure electrode for storing energy can be extended to other materials.

Coexisting Fe single atoms and nanoparticles on hierarchically porous carbon for high-efficiency oxygen reduction reaction and Zn-air batteries

Fe single-atom catalysts still suffer from unsatisfactory intrinsic activity and durability for oxygen reduction reaction (ORR). Herein, the coexisting Fe single atoms and nanoparticles on hierarchically porous carbon (denoted as Fe-FeN-C) are prepared via a Zn5(OH)6(CO3)2-assisted pyrolysis strategy. Theoretical calculation reveals that the Fe nanoparticles can optimize the electronic structures and d-band center of Fe active center, hence reducing the reaction energy barrier for enhancing intrinsic activity. The Zn5(OH)6(CO3)2 self-sacrificial template not only can promote the formation of Fe single atoms, but also contributes to the construction of microporous/mesoporous/macroporous structures. Therefore, the obtained Fe-FeN-C exhibits impressive ORR activity with a half-wave potential of 0.921 V, which far exceeds Pt/C. With Fe-FeN-C as the cathode catalyst, the assembled Zn-air batteries delivered a maximum power density of 206 mW cm−2 and a long-cycle life over 400 h.

The Impact of Hybrid Energy Storage System on the Battery Cycle Life of Replaceable Battery Electric Vehicle

Compared with batteries, ultracapacitors have higher specific power and longer cycle life. They can act as power buffers to absorb peak power during charging and discharging, playing a role in peak shaving and valley filling, thereby extending the cycle life of the battery. In this article, a replaceable battery electric coupe SUV equipped with a lithium iron phosphate (LiFePO4) power battery is taken as the research object, and a vehicle dynamics simulation model is established on the MATLAB/Simulink platform. Parameter matching and control optimization for a hybrid energy storage system (HESS) are conducted. Through a proven semiempirical cycle model of the LiFePO4 power battery, the operating cycle life model is derived and used to estimate the battery cycle life. World Light Vehicle Test Cycle (WLTC) simulation results show that the HESS with 308 ultracapacitors can extend the cycle life of the LiFePO4 power battery by 34.24%, thus significantly reducing the operation cost of the battery replacement station.

Production of Porous Carbon by the Synergistic Chemical and Physical Activations and its Capacitive Performance

Biomass-derived carbons have been extensively investigated for supercapacitor applications thanks to their advantages such as high specific capacitance value, low cost, environmental friendliness, and readily available natural materials. In this study, unique oxygen-rich porous carbons were successfully prepared by combining chemical KOH and physical CO2 activation methods. The physical and textural properties of as-prepared carbon materials are highly dependent on the synthesis conditions. The resulting PC-4K-CO2 porous carbon exhibited a hierarchical porous structure consisting of micropores, mesopores, and macropores along with a large surface area of 1318.4 cm2/g, which allowed high exposure of electrocatalytic sites and ion diffusion/transfer facilitated. As a supercapacitor electrode material, PC-4K-CO2 porous carbon prepared at 800 °C with synergic activation of KOH and CO2 showed the highest specific capacitance of 151 F/g at a current density of 0.5 A/g in the 1 M KOH electrolyte. Besides, the electrode prepared with the PC-4K-CO2 sample has achieved an excellent long-cycling life with only an 8.6% loss of its initial capacitance over 500 cycles even at a current density of 5 A/g. The current study emphasizes the environmental significance of turning pistachio shells into electrode materials for high-performance supercapacitors.