High Energy Density Research Articles

Phase transition, antiferroelectric and pulse discharge properties of (1-x)NaNbO3–xBi2/3ZrO3 ceramics

In present work, a novel ceramic composition of (1-x)NaNbO3-xBi1/3ZrO3 was designed to break through the bottleneck that high energy density (Wd) and power density (PD) are difficult to coexist for pulse discharge applications. The modified ceramics exhibited well-defined double P-E loops, a high PD of ∼22.5 MW/cm3 and a high Wd of ∼0.22 J/cm3 simultaneously, superior to other published works. The structural analysis showed that the unstable antiferroelectric P phase gradually transforms into the stable R phase after Bi1/3ZrO3 modification, mainly due to the great decrease of P-R transition temperature to 175 oC. In addition, P-E and I-E results under large signals further demonstrated the phase transition from P to R phase. Our work provides a significant way to regulate the phase transition of sodium niobate.

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.

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.

Effects of boundary conditions on flash boiling ammonia sprays from a twin-fluid atomizer

Ammonia is a carbon-free fuel with a high hydrogen capacity (17.8 wt%) and well-established production and distribution infrastructures, making it a viable option for decarbonized and dispatchable power. In addition, ammonia combustion in its liquid phase is preferred for simplified storage, higher energy density, and compatibility with high-pressure industrial conditions. However, ammonia fuel has drawbacks that must be addressed. This work aims to investigate experimentally the effect of the boundary conditions on the dynamics of an ammonia spray injected by a commercial twin-fluid atomizer in a chamber at room pressure and temperature. A flash boiling analysis was conducted to assess the thermodynamic conditions that promote this phenomenon and the accuracy of existing correlations to predict this transition to flash boiling. The result showed that low injection pressures and preheated atomizing flow promote the formation of bubbles and the subsequent collapse inside the atomizer, creating an unstable spray. Such instabilities are significantly reduced when the injection pressure is increased. Additionally, increasing the atomizing air flow, injection pressure, and atomizing flow temperature improves the fuel breakup, widening the spray angle. However, the spray angle decreases at a certain point, indicating that atomization is more sensitive to thermodynamic conditions than a mechanical breakup.

Ni-modified BaTiO3 film prepared by sol-gel with high energy storage performance

The development of lead-free dielectric capacitors with high recoverable energy storage density and high energy storage efficiency is important for improving the overall performance of electronic and power systems. BaTiO3 (BTO) is one of the most common ferroelectric materials and has attracted much attention for energy storage applications in the past decades due to its excellent dielectric and ferroelectric properties. However, high remnant polarization and low electrical breakdown strength of BTO limit its development in energy storage applications. Many efforts (e.g., elements doping, interface/heterostructure, etc.) have been made to improve the energy storage density of BTO thin films. In this paper, Ba1-xNixTiO3 thin films (x = 0, 0.02, 0.04, 0.06, 0.08; abbreviated as BNxT) were synthesized via sol-gel and spin-coated method. The effect of Ni doping on the structural, dielectric, ferroelectric and energy storage properties of BTO thin films has been studied. The results confirmed that with the increase of Ni doping, a second phase arises and the dielectric constant decreases. While appropriate Ni doping led to the improvement of the breakdown strength, further increase of Ni deteriorated the energy storage because of the high oxygen vacancy. Finally, optimized energy storage performance was obtained for BN0.04T thin film: dielectric constant of 401, dielectric loss of 0.002, recoverable energy density of 20.2 J/cm3 and energy storage efficiency of 83.6% at 965 kV/cm. Meanwhile, the remnant and maximum polarization of the films were 0.06 μC/cm2 and 50 μC/cm2, respectively. BN0.04T thin film has an excellent application prospect and is expected to appear as a component in the future composite energy storage film system.

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.

Efficient hybrid supercapacitor performance enabled by large surface area of 2D mesoporous zinc sulfide nano-sheets synthesized via microwaves

Researchers have shown a significant amount of interest in synthesizing high energy density supercapacitors using a simplest, fast, and low cost technique. The electrochemical performance of supercapacitors can be impacted by the surface area and morphology of electrode materials. A one-step, rapid, and economical microwave-assisted synthesis technique was employed in this study in order to prepare mesoporous nanosheets that are composed of zinc sulfide. The ZnS-based nanosheets possess a large surface area of ∼120 m2g−1 and a mesoporous structure of a pore diameter of <22 nm, which offers numerous electrochemical active sites and it facilitates an excellent super capacitive performance, which is due to its shortened ion/electron diffusion path. The prepared mesoporous nanosheets exhibit a higher specific capacitance of 2282 Fg−1 (1037 C/g) when subjected to a 1 Ag−1 in 2 M KOH aqueous electrolyte with high capability rate. The fabricated device exhibits a high specific capacitance of 252.5 Fg−1 (140 C/g) at 1 Ag−1, which produces a remarkable energy density of about 90 Whkg−1 at 800 Wkg−1 value of power density and an excellent retention of ∼95 % after 10,000 cycles at 6 Ag−1. This study designed an instant, straightforward and low-cost approach to fabricate ZnS nanosheet electrode materials that exhibit excellent performance for supercapacitor applications.

High-resolution 3D hydrodynamic modeling and comprehensive assessment of tidal current energy resources

As a clean and renewable resource, tidal current holds significant development potential. However, accurately assessing tidal current energy resources has been a persistent challenge. This study proposes a comprehensive assessment method using a small-scale, high-precision, multi-criteria three-dimensional hydrodynamic model to assess resource reserves applied to the Zhairuoshan Waterway. The hydrodynamic model was employed to simulate critical parameters such as tidal level, flow velocity, and flow direction. Multiple statistical indicators were used to evaluate the model's accuracy, showing consistency. The study analysed the flow speed distribution over a complete cycle, revealing an average flow speed of 1.51 m/s, with a maximum speed reaching 3.83 m/s. The generally high flow speeds within the waterway, coupled with the stability of the tidal current, indicate the significant resource potential of the study area. A quantitative analysis of the spatial distribution of tidal current energy was conducted using energy flux density, and the results showed that high energy density areas are widely distributed. Furthermore, the theoretical tidal energy resources of the waterway were calculated, showing that the maximum resource reserves could reach 9.98 MW at the selected cross-sections. Coupled with the analysis of unit-width energy flux, the high-potential areas within the waterway were further identified.

Investigating the environmental impacts of lithium-oxygen battery cathode production: A comprehensive assessment of the effects associated with oxygen cathode manufacturing

Lithium-oxygen batteries offer remarkably high energy density compared to current lithium-ion batteries. The key to their electrochemical performance lies in the processes occurring at the air cathode. However, the complexity of these reactions, coupled with the by-products generated during discharge, can make the reaction process slow or impede their efficiency. This study evaluates the environmental impact of high-efficiency lithium-oxygen batteries cathodes, including titanium oxide composites, graphene-based composites and activated carbon-based composites, through a life cycle assessment across 18 impact categories using a cradle-to-gate approach with a functional unit of 25 kWh. Results show that active material production was the largest contributor to environmental impact, particularly Global Warming Potential. Among the evaluated cathodes, reduced graphene oxide/α-mnaganese oxide/palladium (rGO/α-MnO2/Pd) demonstrated the highest environmental impact, with a global warming potential of 1130.71 kg carbon dioxide from active material production, due to its energy-intensive synthesis and the use of chemicals like sulfuric acid, sodium borohydride, hydrochloric acid, and hydrogen peroxide. Additionally, the rGO/α-MnO2/Pd cathode had the highest Human Toxicity Potential and Ozone Depletion Potential. Batteries with graphene-based cathodes achieved a specific capacity of 7500 mAh.g-1, underscoring their performance potential while highlighting the need for more sustainable cathode manufacturing methods. These findings emphasize the environmental considerations necessary for large-scale lithium-oxygen batteries implementation.

Energy-loss process in Ni63 betavoltaic batteries

The betavoltaic effect is characterized by multiple random scatterings and high energy density exchange. The conversion of beta-particles’ energy to electric current is a sophisticated process. A GEANT4-based code is used to model the energy-loss mechanisms of emitted electrons from 63Ni radioisotope, considering the physics behind these losses (such as Coulomb scattering, nuclear stopping, and Bethe-Bloch theory) while taking into account self-absorption and backscattering factors. The study indicates the existence of a significant non-ionizing energy-loss of penetrating beta-particles that may stimulate remarkable local heating in the absorbing structure, which results in a degradation in the performance of betavoltaic batteries using 63Ni as nuclear fuel

0D-1D-2D Multidimensional Heterostructure Films for High-Performance Flexible Microsupercapacitors.

Planar microsupercapacitors (MSCs) are of great value for flexible and wearable electronics. The rational design of electrode materials with rapid ionic kinetics and sufficient active site exposure is critical but challenging for realizing high-energy MSCs. Herein, we report the dot-tube-sheet multidimensional heterostructure films (MHFs) with versatile patterns by a simple mask-assisted strategy, consisting of 0D carbon dots (CDs), 1D carboxyl-carbon nanotubes (c-CNTs), and 2D Ti3C2 MXene nanosheets. Thanks to the high electrical conductivity, enlarged interlayer spacing, abundant porous channels, and excellent mechanical strength, the CDs/c-CNTs/Ti3C2 MHF electrodes deliver a remarkable areal capacitance of 1162.6 mF cm-2 at 0.8 mA cm-2 and prominent cycling stability (107.1% capacitance retention after 10,000 cycles) in a 1 M H2SO4 electrolyte. Moreover, the fabricated solid-state CDs/c-CNTs/Ti3C2 MSCs achieve a high energy density (11.1 mWh cm-2) and long-term cycling lifespan (102.1% capacitance retention after 8000 cycles), superior to those of state-of-the-art MSCs. The parallel and serial interconnected modular power sources highlight the potential for powering the actual energy consumption products.

Electrochemical Mechanism Underlying Lithium Plating in Batteries: Non-Invasive Detection and Mitigation

Efficient, sustainable, safe, and portable energy storage technologies are required to reduce global dependence on fossil fuels. Lithium-ion batteries satisfy the need for reliability, high energy density, and power density in electrical transportation. Despite these advantages, lithium plating, i.e., the accumulation of metallic lithium on the graphite anode surface during rapid charging or at low temperatures, is an insidious failure mechanism that limits battery performance. Lithium plating significantly shortens the battery’s life and rapidly reduces capacity, limiting the widespread adoption of electrical vehicles. When lithium plating is extreme, it can develop lithium dendrites, which may pass through the separator and lead to an internal short circuit and the subsequent thermal runaway damage of the cell. Over the last two decades, a large number of published studies have focused on understanding the mechanisms underlying lithium plating and on approaches to mitigate its harmful effects. Nevertheless, the physics underlying lithium plating still needs to be clarified. There is a lack of real-time techniques to accurately detect and quantify lithium plating. Real-time detection is essential for alleviating lithium plating-induced failure modes. Several strategies have been explored to minimize plating and its effect on battery life and safety, such as electrolyte design, anode structure design, and hybridized charging protocol design. We summarize the current developments and the different reported hypotheses regarding plating mechanisms, the influence of environmental and electrochemical conditions on plating, recent developments in electrochemical detection methods and their potential for real-time detection, and plating mitigation techniques. The advantages and concerns associated with different electrochemical detection and mitigation techniques are also highlighted. Lastly, we discuss outstanding technical issues and possible future research directions to encourage the development of novel ideas and methods to prevent lithium plating.

Carbon-Free H2 Production from Ammonia Decomposition over 3D-Printed Ni-Alloy Structures Activated with a Ru/Al2O3 Catalyst

Hydrogen, with its high energy density and zero greenhouse gas emissions, is an exceptional energy vector, pivotal for a sustainable energy future. Ammonia, serving as a practical and cost-effective hydrogen carrier, offers a secure method for hydrogen storage and transport. The decomposition of ammonia into hydrogen is a crucial process for producing green hydrogen, enabling its use in applications ranging from clean energy generation to fueling hydrogen-powered vehicles, thereby advancing the transition to a carbon-free energy economy. This study investigates the catalytic performance of various 3D-printed porous supports based on periodic open cellular structures (POCS) and triply periodic minimal surface (TPMS) architecture manufactured from IN625 nickel alloy powder using the laser powder bed fusion (LPBF) technique. The POCS and TPMS, featuring geometries including BCC, Kelvin, and Gyroid, were analyzed for cell size, strut/sheet diameter, porosity, and specific surface area. Pressure drop analyses demonstrated correlations between structural parameters and fluid dynamics, with BCC structures exhibiting lower pressure drops due to their higher porosity and the open channel network. The dip/spin coating method was successfully applied to activate the supports with a commercial Ru/Al2O3 catalyst, achieving uniform coverage crucial for catalytic performance. Among the tested geometries, the Gyroid structure showed superior catalytic activity towards ammonia decomposition, attributed to its efficient mass transfer pathways. This study highlights the importance of structural design in optimizing catalytic processes and suggests the Gyroid structure as a promising candidate for improving reactor efficiency and compactness in hydrogen production systems.

Making Sense of the Relationship Between Ultra-Processed Foods, Obesity, and Other Chronic Diseases

Ultra-processed foods (UPFs) is a food category within the NOVA system. The key feature of UPFs are foods that have been highly processed and contain various additives, especially those that are industrially produced. It is claimed that UPFs are inherently unhealthy. The classification system is highly controversial. This paper critically evaluates the evidence. In stark contrast to conventional systems for food classification, the NOVA system disregards the nutritional values of foods. As a result, many foods generally considered to be healthy are included as UPFs, whereas many unhealthy foods are excluded. Epidemiological studies, mainly prospective cohort studies, have consistently reported an association between the intake of UPFs and risk of obesity, cardiovascular disease (CVD), type 2 diabetes, common mental disorders (especially depression), and all-cause mortality. A similar association has been reported for cancer and hypertension, but the supporting evidence is weaker. The most plausible explanation for this is that the associations are largely due to a limited number of unhealthy foods, such as processed meat and sugar-sweetened beverages. Studies of the relationship between UPFs and obesity present a different picture. There is much evidence that suggests that UPFs play a major causal role in obesity. The high contents of fat, sugar, carbohydrates, and sodium commonly present in UPFs makes these foods hyperpalatable. In addition, UPFs typically have a high energy density. As a result of these two features of UPFs, most people consume an excessive energy intake when presented with UPFs. Because UPFs include a wide range of foods, many of which are healthy, it is likely that while many UPFs are obesogenic, many others are not.

Cold Sintering Halide-in-Oxide Composite Solid-State Electrolytes with Enhanced Ionic Conductivity.

All-solid-state batteries (ASSBs) have attracted increasing attention for next-generation electrochemical energy storage due to their high energy density and enhanced safety, achieved through the use of nonflammable solid-state electrolytes (SSEs). Oxide-based SSEs, such as Li1.3Al0.3Ti1.7(PO4)3 (LATP), are notable for their high ionic conductivity and excellent chemical and electrochemical oxidation stability. Nevertheless, their brittle mechanical properties and poor interface contact with electrode materials necessitate high-temperature and long-duration sintering or postcalcination processes, limiting their processability for real-world applications. Additionally, the formation of secondary phases can detrimentally affect the ionic conductivity of LATP electrolytes. Emerging halide-based SSEs offer reliable deformation for practical processing while maintaining high ionic conductivity. In this work, we report a transient liquid-assisted cold sintering process to integrate oxide-based LATP as the matrix and halide-based Li3InCl6 as the conductive boundary phase into a halide-in-oxide ceramic composite electrolyte at a low processing temperature of 150 °C. This composite structure significantly reduces interface resistance, effectively addressing ion-transport depletion across the boundaries between LATP particles. Consequently, the cosintered LATP-Li3InCl6 composite SSE exhibits a high ionic conductivity of 1.4 × 10-4 S cm-1 at ambient temperature. Furthermore, the symmetric Li|LATP-Li3InCl6·nDMF|Li cell demonstrates stable stripping and plating processes for 1600 h at 55 °C (0.1 mA cm-2) and 1200 h at 100 °C (1 mA cm-2). This work represents the first demonstration of halide-oxide ceramic composite SSEs that combine the advantages of oxides and halides for high-performance SSBs.

Boosting Li‐Metal Anode Performance with Lithiophilic Li–Zn Seeds in a 2D Reduced Graphene Oxide Scaffold

AbstractThe substitution of conventional graphite with Li metal as an anode material has garnered significant interest due to its exceptionally high theoretical energy density. However, the direct application of Li metal as an anode in batteries faces formidable challenges, including dendrite growth and interphase instability. Herein, a high‐performance composite anode (LZ‐rGO) that integrates a reduced graphene oxide (rGO) scaffold with lithiophilic Li–Zn alloy nanoparticles is presented. The Li–Zn seeds embedded in the structure lower the initial nucleation barrier and facilitate uniform Li deposition. Furthermore, the rGO scaffold, possessing a large specific surface area, enables the LZ‐rGO anode to significantly reduce voltage hysteresis and prevents the deactivation of metallic Li during the plating/stripping processes. As a result, the symmetric cell demonstrates stability over 1200 h at a current density of 1 mA cm−2, with negligible voltage fluctuation. When paired with a LiFePO4 cathode, the full cell achieves stable cycling for 1000 cycles with a high‐capacity retention, demonstrating exceptional interface stability and cycling efficiency.

Deep P‐C Interface Reconstruction for High‐Performance Potassium Storage

AbstractPotassium‐ion batteries (PIBs) capable of achieving full charge in minutes, or even in seconds, while maintaining high energy densities, are highly desirable for practical applications. However, significant challenges exist in developing electrodes that can sustain both high capacity and rapid charging rates. Conventional phosphorus‐carbon composites, limited by the intrinsic common carbon materials structure, often fail to prevent the edges reconstruction of black phosphorus (BP), thereby limiting its potential advantages as a high‐capacity, high‐rate anode. This study addresses these challenges by grafting BP onto a super‐porous carbon (SPC) framework to serve as an anode for potassium storage. The large number of open pores in SPC ensures the uniform distribution of BP nanoparticles in this carbon matrix, realizing the complete potassiation reactions and uniform volumetric strain dispersion. The abundant defects significantly promote the phosphorus‐carbon reconstruction between edge carbon atoms and edge phosphorus atoms, effectively inhibiting the P‐P edge reconstruction of BP to ensure open edges for rapid K+ diffusion. As a result, the composite exhibits excellent performance in potassium storage, demonstrating superior capacity, charging rates, and cycling durability. This research provides a new insight into enhancing BP‐base anodes, offering favorable guidance for the development of high‐performance materials.

Sodiophilic Interface and Electrolyte Regulation Boost the Lifespan of Anode‐Free Sodium Battery

ABSTRACTAnode‐free sodium batteries (AFSBs) have attracted increasing attention for their high energy density. However, they suffer from rapid capacity decline resulting from sodium dendrite growth at the sodium/host interface and irreversible side reactions at the electrolyte/sodium interface. Herein, a GaInSn‐coated Cu foil (G‐Cu), prepared by a simple brush coating method, was applied as the sodiophilic current collector to regulate sodium nucleation behavior. In addition, a nonexpendable functional electrolyte additive, hexamethyldisiloxane (HMDSO), was introduced, which could be absorbed on the sodium surface and serve as a protective layer against corrosion side reactions at the electrolyte/sodium interface. It is interesting to note that this additive barely participated in forming the solid electrolyte interphase. The synergetic effects of sodiophilic interface design and electrolyte regulation enable reversible sodium plating and stripping. Ultimately, the AFSB assembled using G‐Cu and HMDSO electrolyte with a highly loaded Na3V2(PO4)3 cathode (≈12.5 mg cm−2) delivers a discharge capacity of 84.5 mAh g−1 after 200 cycles with a high capacity retention of 87.6%, significantly extending its operation lifespan.

Flux Synthesis of Robust Polyimide Covalent Organic Frameworks with High-Density Redox Sites for Efficient Proton Batteries.

Aqueous proton batteries are attracting increasing attention in the large-scale next-generation energy storage field. However, the electrode materials for proton batteries often suffer from low specific capacity and unsatisfactory cycle durability. Herein, we synthesize two highly crystalline and robust polyimide covalent organic frameworks (COFs) through a solvent-free flux synthesis approach with benzoic acid as a flux and catalyst. The as-synthesized COFs possess enriched redox-active sites for proton storage and intrinsic Grotthuss proton conduction, rendering them ideal candidates for proton electrode materials. The optimal COF electrodes achieve a high specific capacity of 180 mAh/g at 0.1 A/g, among the highest COF-based proton batteries, and exhibit an outstanding rate capability of up to 100 A/g and long-term cycling stability with capacity retention of 99% after 5000 cycles at 5 A/g. The assembled full cells deliver a specific capacity of 150 mAh/g at 0.2 A/g with a maximum energy density of 72 Wh/kg and a maximum supercapacitor-level power density of 64 kW/kg, surpassing all reported COF-based systems. This work paves a new avenue for the design of electrode materials for aqueous proton batteries with high energy density, power density, rate capability and long-term cycling stability.

Enhanced Energy Storage Properties of PP/PA11 Dielectric Composite Films With PP‐g‐MAH as Compatibilizer

ABSTRACTAs an energy storage capacitor film material, polypropylene (PP) suffers from its low dielectric constant and limited energy density. To overcome the defects of pure PP, the PP‐based all‐organic composite films with multiple interfaces have been constructed to enhance the dielectric and energy storage properties. In this research, PA11 was used to blend with PP with polypropylene grafted maleic anhydride (PP‐g‐MAH) as compatibilizer. The prepared PP/PP‐g‐MAH/PA11 composites formed the typical “sea‐island” structure and double interfaces between PP/PP‐g‐MAH and PP‐g‐MAH/PA11. The higher molecular polarity of PP‐g‐MAH, PA11, and interfacial polarization significantly increases the dielectric constant of the composite films. Furthermore, the formation of interface traps suppressed the migration of charge carriers, resulting in lower leakage current and higher breakdown strength of the PP/PP‐g‐MAH/PA11 composite films. Density functional theory (DFT) simulation further proved the confinement of space charges. Energy storage results showed the optimal PP/PP‐g‐MAH/PA11‐2 film achieved high energy density (4.49 J/cm3) and excellent charge/discharge efficiency (97.4%), which behaved good application prospect in the field of thin film capacitors.