Reduced Energy Density Research Articles

Investigation of Rate Capability and Mass Transfer Dynamics in Lithium-Ion Batteries

Lithium-ion batteries are poised to play a pivotal role in achieving net-zero emissions amidst the ongoing global green transition. The quest for new and sustainable battery chemistries is imperative to meet the anticipated increase in demand. Consequently, the development of cost-effective electrochemical techniques holds significant importance in advancing battery research. Ongoing efforts aim to surpass conventional energy storage solutions, focusing on enhancing energy density and capacity. Thicker electrodes offer a promising pathway for enhancing the electrochemical performance of lithium-ion batteries (LIBs); however, their utilization presents challenges stemming from issues such as increased tortuosity, cracking, and delamination. These challenges ultimately compromise electrode mechanical integrity and reduce energy density, particularly at higher C rates. Addressing these challenges requires exploring the mass transport properties within the electrodes to enhance diffusion. Investigating the rate capabilities and the phenomenon of electrode mass transport presents an opportunity to gain comprehensive insights into the diffusion processes, which is essential for optimizing LIB performance [1], [2].In this study, cathodes were fabricated using lithium nickel manganese cobalt oxide (NMC111) as the active material, employing two different binders and corresponding solvents: the conventional binder polyvinylidene fluoride (PVDF) with N-methyl-2-pyrrolidone (NMP), and a more sustainable alternative utilizing lignin as the binder and water as the solvent. These cathodes were integrated into half-cells, and their electrochemical performance was assessed through galvanostatic cycling. The rate performance analysis revealed an improvement in performance correlating with electrode thickness, reaching an optimal point where capacity retention begins to decline. The PVDF/NMP cathodes utilized for assessing rate performance exhibited active mass loadings ranging from 3.4 ± 0.2 to 19.8 ± 0.5 mg/cm2. Notably, a notable decline in specific discharge capacity was observed at higher C-rates as the active mass loadings decreased for PVDF/NMP half-cells. Among these, electrodes with an active mass loading of 3.4 ± 0.2 mg/cm2 demonstrated superior performance, achieving a specific discharge capacity of 95 mAh/g at 5.0 C.The main overpotentials (ohmic, reaction, and concentration) were investigated by plotting cell potentials against current densities in lignin/water and PVDF/NMP half-cells. This facilitated the calculation of the effective mass transfer coefficient using two definitions of state of charge (SoC): nominal, referencing the initial capacity, and dynamic, based on the capacity achieved in each cycle. This analysis aimed to explore cathode characterization possibilities and evaluate the influence of the binder. Mass transport analysis indicated that cathodes fabricated with lignin and utilizing nominal SoC yielded more anticipated curves and reliable outcomes than those using PVDF/NMP. Polarization curves revealed that lignin/water cathodes exhibited the highest concentration overpotentials. However, challenges were observed in estimating ohmic resistance. Additionally, the results demonstrated that the effective mass transfer coefficient declines with increasing current indicative of a larger diffusion layer at lower SoC.

Environmental Impact Assessment of Utilizing Palm Oil as Biofuel for Engines

This study examines the techno-environmental analysis of utilizing palm oil as biofuel for engines. It aims to assess transesterification, pyrolysis, and hydrogenation processes for palm oil based biodiesel production, and evaluate the effect of crude palm oil on the performance of engine and emissions through Environmental Impact Assessment (EIA). The investigation focuses on the influence that palm oil biodiesel has on the performance of engine, emphasizing power and torque output, considering engine speed and biodiesel blend ratio. A sensitivity analysis using relevant research data will illustrate their interaction effects. Additionally, it will examine the potential for additional fuel use due to biodiesel’s reduced energy density. By integrating technical and economic analyses, this work provides insights into the feasibility and palm oil green diesel impact as a fuel alternative for engines. Results showed that SPOP, IPOP, and CPOP reported 18.52%, 33.33%, and 48.15% GHG emission. A comprehensive analysis of GHG emissions data for the three consecutive years 2019, 2020, and 2021 shows that energy sector and industrial processes reported the highest and lowest contributions to the overall emission of GHG respectively. The environmental impact assessment results for different stages of palm oil based biodiesel production reveals that the cultivation stage emits 2,762 kg of carbon dioxide (CO2) equivalent per functional (epf) unit, the eutrophication stage emits 0.12 kg of phosphorus epf unit, the acidification stage emits 0.06 kg of sulfur dioxide epf unit, and the photochemical oxidation stage emits 0.02 kg of ethylene epf unit. Palm oil biodiesel shows higher heat release rate than diesel suggesting that it is more environmentally friendly and provide more energy per unit of fuel compared to diesel.

Direct contact pre-lithiation for practical lithium ion batteries: Focus review

Pre-lithiation methods address the challenges of low initial coulombic efficiency (ICE) and reduced energy density in lithium-ion batteries (LIBs) by adding additional lithium sources to compensate for initial irreversible Li+ losses. The direct contact pre-lithiation (DC-Pr) method has garnered extensive attention due to its simplicity, convenience as well as significant effects on the improved cycling durability. Considering the most important factors, i.e., effectiveness and uniformity, this review focuses on the anode DC-Pr method for LIBs with the lithium sources from Li foil, stabilized lithium metal powder (SLMP), lithium-rich alloys, and physical vapor deposition of lithium metal. After summarizations and discussions, the review overviews the challenges and prospects for DC-Pr methods, aiming to provide guidance for the construction and developments of practical LIBs.

Mechano‐Electrochemical Behavior of Nanostructured Li‐ and Mn‐Rich Layered Oxides with Superior Capacity Retention and Voltage Decay for Sulfide‐Based All‐Solid‐State Batteries

AbstractLi‐ and Mn‐rich layered oxides (LMROs) are recognized as promising cathode materials for lithium‐ion batteries (LIBs) due to their high specific capacity and cost efficiency. However, LMROs encounter challenges such as manganese dissolution in electrolytes and the release of oxygen gas from irreversible oxygen redox reactions, leading to structural degradation and voltage decay that reduce energy density. Consequently, recent research has shifted toward employing LMROs in all‐solid‐state batteries (ASSBs), where Mn dissolution is negligible. Herein, nanostructured LMROs demonstrate superior electrochemical compatibility with sulfide‐based solid electrolytes in ASSBs compared to conventional LIBs. Nanostructured LMRO exhibits outstanding capacity retention (97.1% after 1300 cycles at 30 °C) with significantly suppressed voltage decay. Furthermore, the initial electrochemical activation of Li2MnO3 domains within LMRO is explored in terms of the mechano‐electrochemical interactions in the composite cathode. At elevated temperatures, interfacial degradation accelerates due to the chemical oxidation of Li6PS5Cl solid electrolytes, driven by oxygen released from LMRO. To address this, LMRO surfaces are modified with thioglycolic acid through esterification, suppressing interfacial degradation of Li6PS5Cl and ensuring stable capacity retention over 500 cycles at 60 °C. These findings underscore the potential of LMRO materials as promising cathode options for ASSBs, surpassing those used in LIBs.

Enhancing reaction kinetics in aprotic magnesium-air batteries using a freestanding flexible metal-free carbon fiber cathode

Metal-air batteries hold great promises for future energy storage, driven by their impressive energy density. However, practical applications encounter challenges due to the sluggish kinetics of oxygen reduction and evolution reactions taking place at cathode interface, particularly in demanding conditions such as high-current density and open-air scenarios. Addressing these challenges requires cathodes with high reactivity and optimized structure to efficiently facilitate electrochemical reactions. This necessitates the development of self-supporting cathodes that eliminate the current electrode fabrication process, which can lead to binder-induced blockage of reactive sites and reduce energy density due to heavy current collectors. Here, we propose an effective strategy to design freestanding cathodes with high reactivity and a well-designed hierarchical pore structure. This cathode significantly enhances battery reaction kinetics while accommodating insoluble discharge products and preserving air and electrolyte transport pathways for high-performance Mg-air batteries. The freestanding flexible metal-free carbon fiber cathode (E-CNFs) enables a Mg-air battery operating in an open-air condition to exhibit an ultralow overvoltage of 0.4 V as well as delivered a long-term lifetime of 280 h. As a result, an impressive full discharge capacity of 5772 mAh/g under a current density of 800 mA g−1 is achieved, surpassing those in all previously reported Mg-O2/air batteries.

Construction of Adaptive Deformation Block: Rational Molecular Editing of the N-Rich Host Molecule to Remove Water from the Energetic Hydrogen-Bonded Organic Frameworks.

Energetic hydrogen-bonded organic frameworks (E-HOFs), as a type of energetic material, spark fresh vitality to the creation of high energy density materials (HEDMs). However, E-HOFs containing cations and anions face challenges such as reduced energy density due to the inclusion of crystal water. In this work, the modification of amino groups in N-rich organic units could form a smart building block of hydrogen-bonded frameworks capable of changing the volume of the void space in the molecule through adaptive deformation of E-MOF blocks, thus enabling the replacement of water. Based on the above strategy, we report an interesting example of a series of hydrogen-bonded organic frameworks (E-HOF 2a and 3a) synthesized using a facile method. The crystal structure data of all of the compounds were also obtained in this work. Anhydrous 2a and 3a exhibit higher density, good thermal stability, and low mechanical sensitivity. The strategy of covalent bond modification for the host molecules of energetic frameworks shows enormous potential in eliminating the crystalline H2O of hydration and exploring high energy density materials.

Surface modification of perforated separator for more robust and thinner all‐solid‐state electrolyte membrane

AbstractSolid electrolytes (SEs) play an essential role in the development of all‐solid‐state batteries (ASSBs) due to their exceptional ionic conductivity. However, conventional pelletized SEs with hundreds of micrometers result in highly reduced energy density and suffer from mechanical brittleness, which delay the commercialization of ASSBs. In this study, we present an innovative approach to fabricate SE membranes with perforated Al2O3 nanolayer‐coated polyethylene (PE) separator as a mechanical supporter. Al2O3‐coated separators exhibit better adhesion with LPSCl particles and better thermal stability. As a result, the SE membrane exhibits thickness of 35 μm while maintaining a superior mechanical tensile strength. Furthermore, when the SE membrane is applied to Li||LiNi0.7Co0.15Mn0.15O2 full‐cells, stable cycling performance over 250 cycles, which is comparable to thick LPSCl pellet cell, can be achieved even with higher conductance (>150 mS). Our results highlight the potential of thin and durable SE membranes in contributing to the commercialization of ASSBs.

Towards the Integration of Direct Contact Prelithiation into the Manufacturing Process for Large-Format Lithium-Ion Batteries

The increasing requirements for high-performance lithium-ion batteries from applications such as electric aviation and electric mobility require further improvement of this energy storage technology. Prelithiation is a method to improve the energy density and lifespan by integrating additional lithium during battery cell production to compensate for occurring irreversible losses of active lithium, which lead to a reduced energy density and capacity fade. Direct contact prelithation incorporates lithium metal in contact to the anode active material to generate a lithium reservoir, which can be consumed by parasitic reactions inside the cell.One factor limiting direct contact prelithiation to laboratory scale is the missing knowledge how to integrate direct contact prelithiation into the manufacturing system of battery cells and how subsequent process steps after lithium insertion are affected. The presented work investigates the effect of direct contact prelithiation on the cell assembly and cell finalization processes of the lithium-ion battery production chain. The occurring challenges to integrate the formed anode-lithium-composite in the cell assembly processes are likely to be similar to those for pure lithium electrodes. The electrolyte filling and formation processes show a high need for adaptation regarding direct contact prelithiation, since the first lithiation of the anode and the formation of the solid electrolyte interphase is already initiated with electrolyte filling. Successful industrialization of direct contact prelithiation requires attention to safety concerns due to exothermic chemical reactions, accurate determination of the solid electrolyte interphase to ensure high cell quality, and streamlining of the currently time-consuming formation process.

Fluorinated porous frameworks enable robust anode-less sodium metal batteries.

Sodium metal batteries hold great promise for energy-dense and low-cost energy storage technology but are severely impeded by catastrophic dendrite issue. State-of-the-art strategies including sodiophilic seeding/hosting interphase design manifest great success on dendrite suppression, while neglecting unavoidable interphase-depleted Na+ before plating, which poses excessive Na use, sacrificed output voltage and ultimately reduced energy density. We here demonstrate that elaborate-designed fluorinated porous framework could simultaneously realize superior sodiophilicity yet negligible interphase-consumed Na+ for dendrite-free and durable Na batteries. As elucidated by physicochemical and theoretical characterizations, well-defined fluorinated edges on porous channels are responsible for both high affinities ensuring uniform deposition and low reactivity rendering superior Na+ utilization for plating. Accordingly, synergistic performance enhancement is achieved with stable 400 cycles and superior plateau to sloping capacity ratio in anode-free batteries. Proof-of-concept pouch cells deliver an energy density of 325 Watt-hours per kilogram and robust 300 cycles under anode-less condition, opening an avenue with great extendibility for the practical deployment of metal batteries.

Effect of Surface Nature on Stripping of in Situ li Anodes and Enhancement of Its Stripping Capacity

Li-metal solid-state batteries (LMSSBs) have been considered disruptive technologies for the widespread adoption of EVs due to their improved safety and higher energy density. Recently, in situ Li anode formation on solid-electrolytes (SEs) has garnered interest owing to its low manufacturing cost, high purity, and enhanced energy density. Thus, there have been intense efforts to understand the mechano-electrochemical properties of in situ Li anodes. Our previous work has demonstrated that the accessible capacity of in situ thin Li decreases as current density increases. This result indicates that more Li will remain inaccessible as the stripping rate increases, leading to the reduced energy density of LMSSB cells. To minimize the amount of inaccessible Li at high stripping rates, it is essential to investigate the factors affecting the stripping capacities of in situ Li and devise a new way to achieve enhanced stripping capacities at high stripping rates.First, this study focuses to understand the correlation between the stripping capacity of in situ thin Li and the nature of the surface. This study demonstrates that the nature of the surface can dramatically affect the stripping capacity. When discharging at room temperature and 3 mA/cm2, approximately 50% of the accessible capacity of in situ plated Li was achieved.Furthermore, this study demonstrates that stripping Li under conditions that more closely resemble an EV duty cycle improves the accessible capacities at high stripping rates. By introducing short intermittent rest periods during stripping, the Li/LLZO interface can be relaxed as Li vacancies at the interface can be moved away, preventing voids to forms. Also, even if voids form at the interface, the growth of voids can be delayed because of rewetting mechanisms during the rest periods.This study is expected to not only provide insight into the stripping properties of in situ Li, but also suggest future guidelines for the practical discharge protocols of anode-free LMSSBs with commercially-relevant discharge rates.

Effects of feed energy density, daily milking frequency, and a single injection of cabergoline on behavior and welfare in dairy cows at dry-off

Drying off dairy cows may challenge animal welfare due to high milk yields. A total of 111 loose-housed Holstein cows yielding >15 kg/d of milk were included in a 2 × 2 × 2 factorial design during dry-off to investigate the effects of reduced feeding level (normal vs. reduced energy density), reduced milking frequency (twice vs. once daily), and administration of a dopamine agonist (saline i.m. injection vs. cabergoline i.m. injection) on behavior in the home pen. During the 7 d before dry-off, cows were fed and milked according to 1 of the 4 feeding level and milking frequency combinations. Within 3 h after the last milking, cows were injected i.m. with 5 mL of either saline or a dopamine agonist (5.6 mg of cabergoline; Velactis, Ceva Santé Animale, Libourne, France; labeled for use only with abrupt dry-off, i.e., no preceding reduction in feeding level or milking frequency before last milking). Cows' behavior during d -1, 0, and +1 relative to the last milking was recorded via video and leg-attached sensors. Cows on the reduced energy density diet spent more time feeding and showed more attempts to feed from other cows' bins on d -1. Throughout the period of observations, cows on the reduced diet spent a lower percentage of lying time with their head raised, a higher percentage of lying time with their legs bent, and less time standing in a vigilant posture than did cows on the normal lactation diet. Reducing the daily milking frequency from 2 to 1 did not result in any clear behavioral signs of discomfort. On d 0, cows injected with cabergoline lay down longer but had their head raised for a shorter percentage of time while lying, compared with cows injected with saline. Cows injected with cabergoline also spent less time feeding than cows injected with saline on d 0, and reduced the time spent drinking from d -1 to d 0. Finally, fewer cabergoline-injected cows used the brush for self-grooming, and, among cows that did use the brush, the cows injected with cabergoline reduced the time spent using the brush from d -1 to d 0. In conclusion, cows injected with cabergoline showed several behavioral changes compared with control cows injected with saline. The behavioral changes shown by cows injected with cabergoline may be indicative of malaise during the first 24 h after injection, raising concern for animal welfare. No behavioral evidence for reduced udder pain in cows injected with cabergoline compared with control cows injected with saline was found. Drying off by reducing the energy density of the diet caused behavioral changes indicative of hunger before dry-off, whereas reducing the milking frequency had no clear effects on behavior.

Cobalt/cerium-based ternary Prussian blue analogs as battery type electrode for supercapacitor applications

Supercapacitors are energy storage devices with remarkable properties including high power density, prolonged operational life, and hasty charging/discharging profile; however, a primary barrier to broad development is reduced energy density. Consequently, efforts have been undertaken to fabricate supercapacitors electrodes that resemble battery-type behavior. Owing to the unique structural characteristics and redox active sites, Prussian blue analogs (PBAs) are becoming attractive electrode materials. Herein, we presented the fabrication of ternary PBA-based electrode i.e., cerium cobalt hexacyanoferrate (CeCoHCF) with improved electrical properties and their characterization through different analytical techniques (SEM, FTIR, EDX, XPS, and XRD). The incorporation of cerium and cobalt together in PBA framework imparts a positive effect on the electrochemical properties. The as-synthesized CeCoHCF exhibits a significant specific capacity of 268.8 mA h g−1 at 1 A g−1 under alkaline conditions (3 M KOH) along with 88.6 % of capacity retention over 1000 cycles. Furthermore, the fabricated electrode exhibited the specific capacity 159.4 mA h g−1 at 1 A g−1 in neutral media (1 M Na2SO4). To investigate the practical application, symmetric supercapacitor device was fabricated that provides improved energy and power density as well as a wide operational voltage of around 1.2 V. Conclusively, PBA-based material can be potential candidates for future storage applications, owing to their outstanding electrochemical performance, chemical resilience, simplicity of synthesis, and low cost.

Na–K Co‐deposition in Liquid‐Alloy Batteries Revealed by Operando Visualization

Despite the great prospects of alkali metal batteries, safety concerns associated with dendrite growth still limit their commercial applications. An attractive alternative is to use the room temperature liquid sodium–potassium alloy as the anode, which inherently prevents dendrite growth. Currently, Na–K alloy anodes allow only Na+ or K+ to be cycled, depending on the choice of electrolyte and ion selectivity of the cathode, which results in reduced energy density of the battery. Herein, the possibility of concurrent use of both Na+ and K+ ions in Na–K alloy anodes is explored, and the working mechanism by operando optical microscopy is investigated. It is found that the type of deposited metal is dictated by both salt and solvent in electrolyte. Impressively, Na–K co‐deposition is observed in KFSI‐DME electrolyte for the first time, which strongly influences the dendrite morphology and evolution. Furthermore, the current density also has a great impact on the deposition pattern, which allows dendrite‐free Na/K deposition on the liquid‐alloy anode. These findings enrich our understanding of the intricate electrochemical behaviors of Na–K binary electroactive alloy systems and offer guidance for the sufficient use of Na and K while avoiding dendrite formation in such liquid‐alloy batteries.

Quantum size effect to induce colossal high-temperature energy storage density and efficiency in polymer/inorganic cluster composites.

Polymer dielectrics need to operate at high temperatures to meet the demand of electrostatic energy storage in modern electronic and electrical systems. The polymer nanocomposite approach, an extensively proved strategy for the performance improvement, encounters the bottleneck of reduced energy density and poor discharge efficiency beyond 150°C. Here, we report a polymer/metal oxide cluster composite prepared based on the "site isolation" strategy. Capitalizing on the quantum size effect, the bandgap and surface defect states of the ultra-small inorganic clusters (2.2nm diameter) are modulated to markedly differ from the regular-sized nanoparticles. Experimental results in conjunction with computational simulation demonstrate that, the presence of ultra-small inorganic clusters can introduce more abundant, deeper traps in the composite dielectric with respect to the conventional polymer/nanoparticle blends. Unprecedented high-temperature capacitive performance including colossal energy density (6.8 Jcm-3 ), ultra-high discharge efficiency (95%) and superior stability at different electric field frequencies, are achieved in these polymer/cluster composites up to 200°C. Along with the advantages in material preparation (inexpensive precursors and one-pot synthesis), such polymer/inorganic cluster composite approach is promising for high-temperature dielectric energy storage in practical power apparatus and electronic devices. This article is protected by copyright. All rights reserved.

Recent advances in hard carbon anodes with high initial Coulombic efficiency for sodium-ion batteries

Initial Coulombic efficiency (ICE) has been widely adopted in battery research as a quantifiable indicator for the lifespan, energy density and rate performance of batteries. Hard carbon materials have been accepted as a promising anode family for sodium-ion batteries (SIBs) owing to their outstanding performance. However, the booming application of hard carbon anodes has been significantly slowed by the low ICE, leading to a reduced energy density at the cell level. This offers a challenge to develop high ICE hard carbon anodes to meet the applications of high-performance SIBs. Here, we discuss the definition and factors of ICE and describe several typical strategies to improve the ICE of hard carbon anodes. The strategies for boosting the ICE of such anodes are also systematically categorized into several aspects including structure design, surface engineering, electrolyte optimization and pre-sodiation. The key challenges and perspectives in the development of high ICE hard carbon anodes are also outlined.

Effects of feeding level, milking frequency, and single injection of cabergoline on blood metabolites, hormones, and minerals around dry-off in dairy cows

This study aimed to investigate the effect of the different dry-off strategies based on reducing feeding level (normal vs. reduced energy density), reducing milking frequency (twice vs. once daily), and administration of a dopamine agonist after last milking (i.e. saline vs. cabergoline injection) on blood metabolites, hormones, and minerals around dry-off. In this experiment, 119 Holstein dairy cows were used in a 2 × 2 × 2 factorial arrangement. In the last week before dry-off, cows were allocated to 1 of the 4 possible dry-off strategies based on feeding level and milking frequency. Within 3 h after last milking, cows were injected with either saline or a D2 dopamine agonist (cabergoline; Velactis, Ceva Santé Animale, Libourne, France; labeled for use only with abrupt dry-off, e.g., no preceding reduction in feeding level or milking frequency before last milking). After dry-off, all cows were fed the same dry cow diet and data collection continued for a week. Blood samples were collected from the coccygeal vein on d -9, -6, -5, -2, 1, 2, 5, and 7 relative to dry-off. Additionally, blood was sampled at 0, 3, and 6 h relative to injection of either cabergoline or saline, equivalent to d 0.125, 0.250, and 0.375 relative to last milking (dry-off). The reduced feeding level before dry-off caused reduced glucose and insulin concentrations as well as increased free fatty acid concentrations, particularly when reduced feeding level was combined with milking the cows 2× daily. The intramuscular injection of cabergoline caused the expected reduction in circulating prolactin concentrations. In addition, dopamine-agonist cabergoline induced an atypical simultaneous pattern of plasma metabolites (i.e., increased glucose and free fatty acid concentrations), hormones (i.e., reduced insulin and increased cortisol concentrations), and minerals (i.e., reduced calcium concentration), indicating that normal metabolic and mineral homeostatic regulations were hindered after the injection of ergot alkaloid cabergoline. In conclusion, reducing milking frequency seems the best management strategy to reduce milk production at dry-off among those tested in this study.

Short-term changes in dietary fat levels and starch sources affect weight management, glucose and lipid metabolism, and gut microbiota in adult cats.

A 2 × 2 factorial randomized design was utilized to investigate the effects of fat level (8% or 16% fat on a fed basis) and starch source (pea starch or corn starch) on body weight, glycolipid metabolism, hematology, and fecal microbiota in cats. The study lasted for 28 d and included a low fat and pea starch diet (LFPS), a high fat and pea starch diet, a low fat and corn starch diet, and a high fat and corn starch diet. In this study, hematological analysis showed that all cats were healthy. The apparent total tract digestibility of gross energy, crude protein, and crude fat was above 85% in the four diets. After 28 d, cats fed the high fat diets (HF) gained an average of 50 g more than those fed the low fat diets (LF). The hematological results showed that the HF diets increased the body inflammation in cats, while the LFPS group improved the glucolipid metabolism. The levels of glucose and insulin were lower in cats fed the LF diets than those in cats fed the HF diets (P < 0.05). Meanwhile, compared with the LF, the concentrations of total cholesterol, triglyceride, and high-density lipoprotein cholesterol in serum were greater in the cats fed the HF diets (P < 0.05). Additionally, both fat level and starch source influenced the fecal microbiota, with the relative abundance of beneficial bacteria, such as Blautia being significantly greater in the LFPS group than in the other three groups (P < 0.05). Reducing energy density and using pea starch in foods are both valuable design additions to aid in the management of weight control and improve gut health in cats. This study highlights the importance of fat level and starch in weight management in cats.

In-situ evolution of CoS/C hollow nanocubes from metal-organic frameworks for sodium-ion hybrid capacitors

Alkaline ion hybrid capacitors bridge the performance gaps between batteries and supercapacitors by combining their merits in terms of energy and power densities. However, the poorly matched electrochemical kinetics between anodes and cathodes leads to reduced energy density and inadequate material utilization. Herein, a hybrid composite has been synthesized by the treatment of a cobalt-based metal–organic-framework (ZIF-67 nanocube), involving the chemical etching-coordination reaction and subsequent carbonization together with sulfidation treatment. The as-prepared material with a hollow structure is composed of nanosized CoS nanoparticles uniformly encapsulated in the mesoporous shells of carbon hollow nanocubes (CoS/C HC). The unique architecture endows CoS/C HC with abundant electrochemical active interfacial sites, good mechanical robustness, and effectively alleviated volume variation. CoS/C HC as electrode material exhibits distinguished sodium storage capabilities relating to specific capacity and prolonged cycling durability at high current densities. Moreover, a sodium-ion hybrid capacitor assembled by using CoS/C HC as anode and activated carbon as cathode delivers an energy density of 199 Wh kg−1 and a power density of 7113 W kg−1. The novel electrode material makes the hybrid capacitors more commercially possible by increasing the utilization of active material and improving structural stability.

Carbon-Binder Optimization for Lithium-Ion Battery Extreme Fast Charge

Battery performance is strongly correlated with electrode microstructure and weight loading of the electrode components. Among them are the carbon-black and binder additives that enhance effective conductivity and provide mechanical integrity. However, these both reduce effective ionic transport in the electrolyte phase and reduce energy density. Therefore, an optimal additive loading is required to maximize performance, especially for fast charging where ionic transport is essential. Such optimization analysis is however challenging due to the nanoscale imaging limitations that prevent characterizing this additive phase and thus quantifying its impact on performance.In this work [1], an additive-phase generation algorithm [2] has been developed to remedy this limitation and identify percolation threshold used to define a minimal additive loading (cf. figure, left). Impact of carbon-black binder (CBD) loading on electrochemical performance has been investigated through a wide array of numerical methods and experiments on NMC/graphite cells. These range from the representation, characterization, and homogenization of electrode microstructures, battery macroscale modeling, and impedance and rate capabilities measurements on various cell formats. The combined work provides information on connectivity/percolation of the solid network, effective solid conductivity and ionic diffusivity, interfacial area, cell capacity, lithium plating, impedance, and transport polarization at the beginning of life (BOL) [1]. Rate capability test demonstrates capacity improvement at fast charge at BOL (cf. figure, right), from 37% to 55%, respectively for high (10%wt) and low (4%wt) additive loading during 6C CC charging (and from 80% to 86% at the end of 10 min 6 CC-CV), in agreement with macroscale model. Improvements are attributed to a combination of lower cathode impedance, reduced electrode tortuosity and cathode thickness [1].[1] F. Usseglio-Viretta et. al., Carbon-binder Weight Loading Optimization for Improved Lithium-ion Battery Rate Capability, submitted to Journal of the Electrochemical Society [2] F. Usseglio-Viretta et. al., SoftwareX, 17, 100915 (2022), https://doi.org/10.1016/j.softx.2021.100915 Figure 1

Carbon-Binder Weight Loading Optimization for Improved Lithium-Ion Battery Rate Capability

Battery performance is strongly correlated with electrode microstructure and weight loading of the electrode components. Among them are the carbon-black and binder additives that enhance effective conductivity and provide mechanical integrity. However, these both reduce effective ionic transport in the electrolyte phase and reduce energy density. Therefore, an optimal additive loading is required to maximize performance, especially for fast charging where ionic transport is essential. Such optimization analysis is however challenging due to the nanoscale imaging limitations that prevent characterizing this additive phase and thus quantifying its impact on performance. Herein, an additive-phase generation algorithm has been developed to remedy this limitation and identify percolation threshold used to define a minimal additive loading. Improved ionic transport coefficients from reducing additive loading has been then quantified through homogenization calculation, macroscale model fitting, and experimental symmetric cell measurement, with good agreement between the methods. Rate capability test demonstrates capacity improvement at fast charge at the beginning of life, from 37% to 55%, respectively for high and low additive loading during 6C CC charging, in agreement with macroscale model, and attributed to a combination of lower cathode impedance, reduced electrode tortuosity and cathode thickness.