Performance Of Storage Devices Research Articles

Anionic Hofmeister Effect Regulated Conductivity in Polyelectrolyte Hydrogels for High-Performance Supercapacitor.

The Hofmeister effect not only affects the stability and solubility of protein colloids but also has specific effects on the polymer molecules. Here, the impact of the Hofmeister effect on the electrochemical properties of polyelectrolyte hydrogels at room temperature and subzero temperature studied for the first time. Polyelectrolyte hydrogels exhibit an anti-polyelectrolyte effect in low concentrations of ammonium salt, while they exhibit an obvious Hofmeister effect in high concentrations of ammonium salt. Kosmotropic ions demonstrate strong interaction with water molecules or polymer chains, resulting in the reduction of conductivity of polyelectrolyte hydrogels. However, chaotropic ions exhibit weak interactions with water molecules or molecular chains, leading to an increase in conductivity. The Hofmeister effect has a more significant effect on the polyzwitterion electrolyte. The conductivity of polyzwitterion hydrogel soaked in chaotropic ion is up to 6.2 mS cm-1 at -40°C. The supercapacitor assembled by polyzwitterion electrolytes maintains a capacitance retention rate of 85% and ≈100% coulomb efficiency after 15 000 cycles at -40°C. This study elucidates the influence of the Hofmeister effect on conductivity in polyelectrolytes and expands the regulatory approach for improving the performance of energy storage devices.

Anionic Hofmeister Effect Regulated Conductivity in Polyelectrolyte Hydrogels for High-Performance Supercapacitor.

The Hofmeister effect not only affects the stability and solubility of protein colloids but also has specific effects on the polymer molecules. Here, the impact of the Hofmeister effect on the electrochemical properties of polyelectrolyte hydrogels at room temperature and subzero temperature studied for the first time. Polyelectrolyte hydrogels exhibit an anti-polyelectrolyte effect in low concentrations of ammonium salt, while they exhibit an obvious Hofmeister effect in high concentrations of ammonium salt. Kosmotropic ions demonstrate strong interaction with water molecules or polymer chains, resulting in the reduction of conductivity of polyelectrolyte hydrogels. However, chaotropic ions exhibit weak interactions with water molecules or molecular chains, leading to an increase in conductivity. The Hofmeister effect has a more significant effect on the polyzwitterion electrolyte. The conductivity of polyzwitterion hydrogel soaked in chaotropic ion is up to 6.2 mS cm-1 at -40°C. The supercapacitor assembled by polyzwitterion electrolytes maintains a capacitance retention rate of 85% and ≈100% coulomb efficiency after 15 000 cycles at -40°C. This study elucidates the influence of the Hofmeister effect on conductivity in polyelectrolytes and expands the regulatory approach for improving the performance of energy storage devices.

Regulation of wood porous structure and construction of reduced graphene oxide@wood derived carbon conducting collector

With the gradual increase in the consumption of non-renewable energy sources, the development of energy storage and conversion devices has become increasingly important. Sustainable self-supporting conductive collectors have become one of the effective ways to enhance the performance of energy storage devices. In this study, the pore modulation technique was implemented on Beijing poplar and camphor pine using delignification and water extraction, and six wood-derived carbon (WC) electrodes were prepared by heat treatment using untreated material as a control. By observing the microscopic morphology, it was found that all six carbon materials retained the graded porous structure characteristic of natural wood. The carbon material prepared from water extraction treated Beijing poplar (WPC) had the best capacitive properties. The conductive reduced graphene oxide (RGO) is composited with WPC, and the constructed RGO@WPC (RWPC) conductive collector has an average conductivity as high as 15.4 S m−1, which provides a strong guarantee for fast electron transport. The specific capacitance of RWPC is as high as 2100 mF cm−2 when the current density is 1 mA cm−2. The constructed RWPC//RWPC energy storage device has a maximum energy density of 3.76 Wh kg−1 and a maximum power density of 171.3 W kg−1. In this paper, a green and efficient self-supporting conductive collector with a graded porous structure is proposed. It also broadens the high value-added utilization of wood in energy storage.

Engineering electrode microstructures for advanced lithium-ion batteries

The architecture of anode materials is an essential factor in improving the performance of energy storage devices, which meets the increasing demand for energy storage and helps achieve environmental sustainability targets. Atomic manufacturing allows the makeup of electrodes to be changed precisely at the atomic level. This facilitates the creation of electrode materials with specific physical properties and enhanced performance. This Perspective reviews the details of how the microstructure design influences key electrode material characteristics. Finally, we anticipate the potential of materials and manufacturing techniques for materials microstructure in the future. A thorough grasp of the materials microstructure in electrode materials is offered by this article.

Cryolithionite‐based Pseudocapacitive Electrode for Sustainable Lithium‐ion Capacitors

Lithium‐ion insertion/deinsertion in anode at slow rates limits the power performance of energy storage devices. Here, a new pseudocapacitive electrode with high reversible capacity during cycling has been proposed for a lithium‐ion capacitor. The lithium‐fluoride garnet, namely Na3Fe2Li3F12, is obtained via precipitation from an aqueous solution at room temperature using abundant materials and exhibits a high discharge capacity of 746 mAh g‐1. After the first charging cycle, energy is stored via fast pseudocapacitive faradaic reactions which are facilitated by the nanocrystalline transport pathways with no structural modification to the electrode. The high stability window of F‐garnet allows extracting cell voltages of 2.2—3.2 V in a lithium‐ion capacitor where it is coupled with a porous carbon‐based positive electrode, with a high energy efficiency of 93 % maintained for 10000 charge/discharge cycles. This study opens new research direction concerning pseudocapacitive anode materials for the enhancing power performance and even replacing the traditional battery‐like anode materials.

Carbon-Based Composites for Oxygen Evolution Reaction Electrocatalysts: Design, Fabrication, and Application.

The four-electron oxidation process of the oxygen evolution reaction (OER) highly influences the performance of many green energy storage and conversion devices due to its sluggish kinetics. The fabrication of cost-effective OER electrocatalysts via a facile and green method is, hence, highly desirable. This review summarizes and discusses the recent progress in creating carbon-based materials for alkaline OER. The contents mainly focus on the design, fabrication, and application of carbon-based materials for alkaline OER, including metal-free carbon materials, carbon-based supported composites, and carbon-based material core-shell hybrids. The work presents references and suggestions for the rational design of highly efficient carbon-based OER materials.

Performance Benchmarking of Redpanda an event streaming platform using SBK and Open Messaging Frameworks

Redpanda is an event-driven, publish/subscribe based messaging system. The two main performance benchmarking frameworks, Storage Benchmark Kit (SBK) and open messaging benchmark are used here to test the performance benchmarking of redpanda’s event processing system. SBK is a software framework for measuring any storage device or client's performance benchmarking and open messaging benchmark framework which supports benchmarking for a wide variety of messaging platforms. Well formulated fine tuning system for benchmarks is still an open research problem. In this paper, SBK and open messaging frameworks have been experimentally compared with respect to their messaging capabilities (Message sending and receiving throughput) on redpanda’s event processing system. A number of experimental test scenarios have been conducted on data streaming workload, the performance evaluation results revealed that SBK gives maximum throughput performance compared to open messaging benchmark.

Two-dimensional Si2C material exhibits efficient conductive properties and outstanding capacitance characteristics in Li/Na/K-ion batteries

To improve the performance of energy storage devices, research into anode materials is essential. This study explores the potential of two-dimensional (2D) materials, particularly silicon carbide (Si2C), to enhance the efficacy of lithium-ion batteries (LIBs), sodium-ion batteries (SIBs), and potassium-ion batteries (KIBs). Our first-principles calculations indicate that Si2C achieves storage capacities of 174.7 mAh g−1 for LIBs, 436.8 mAh g−1 for SIBs, and 349.4 mAh g−1 for KIBs. The exceptional performance of Si2C comes from its high conductivity, large surface area, high capacitance, synergistic atomic radius and electronegativity effects. Furthermore, this study delves into the diffusion kinetics of Li/Na/K-ions in Si2C, revealing extremely low energy barriers and uncovering the fundamental principles behind its superior electrochemical performance. This research emphasizes Si2C’s potential in energy storage, highlighting its capacity and diffusion advantages for Li/Na/K-ion batteries.

Enhanced energy storage performance in Bi4Ti3O12 thin films with oxygen depletion layers

The imprint effect in ferroelectric materials can significantly enhance the performance of energy storage devices. Bi4Ti3O12 (BTO) and oxygen-deficient Bi4Ti3O11.2 (DBTO) thin films were deposited on single-crystal Nb-doped SrTiO3 substrates using pulsed laser deposition. In stark contrast, multilayer DBTO/BTO thin films incorporating an oxygen-deficient layer were also fabricated, with the DBTO layers having thicknesses of 5 nm and 10 nm, respectively. Both BTO and DBTO thin films exhibited epitaxial growth and c-axis-oriented crystallinity. Regarding ferroelectric properties, DBTO/BTO capacitors with an oxygen-deficient layer demonstrated a pronounced imprint effect in their ferroelectric hysteresis loops, compared to the BTO and DBTO capacitors. This effect was particularly noticeable in the DBTO/BTO capacitor with a 10 nm oxygen-deficient layer, as opposed to the thin film with a 5 nm oxygen-deficient layer. We suggest that the imprint effect can be attributed to localized electric field variations and imbalances in charge transport at the interface between the oxygen-depleted layer and the remaining thin film. Consequently, the imprint effect observed in the DBTO/BTO capacitors contributed to an enhancement in energy storage density and efficiency, compared to BTO and DBTO capacitors. This study demonstrates the potential of multilayer DBTO/BTO thin films in advancing capacitive energy storage systems.

Investigation on heat transfer performance of flat plate micro-heat pipe phase change heat storage/release device

In the domains of low/zero carbon energy, the ship energy storage system, coupled with phase-change storage and release technology, holds significant importance. The utilization of a flat micro-heat pipe as the primary heat transfer element prompts the development of a test platform and a transient heat transfer model for the heat storage device. This is in response to existing challenges such as a single structure, poor temperature uniformity, and low thermal efficiency in current heat storage technology. The study delves into the impact of varying temperatures and flow rates of heat transfer fluids on the overall performance of heat storage devices and heat transfer efficiency. The findings highlight that the staggered double plate micro-heat pipe structure can enhance total heat storage by 11%, average heat storage power by 19%, and heat storage efficiency by 21% compared to the heat storage device with a single flat micro-heat pipe structure. It becomes evident that the heat storage device with the staggered double heat pipe structure outperforms its counterpart. Additionally, Temperature and flow velocity play pivotal roles in determining the heat transfer performance of phase change materials. As the temperature difference between the heat transfer fluid and the phase change material increases, both the phase transition rate and the equivalent Nusselt number also rise, providing a crucial foundation for examining the heat transfer characteristics of phase change materials during different stages of phase transition.

Recent Progress of the Application of Electropolymerization in Batteries and Supercapacitors: Specific Design of Functions in Electrodes

AbstractElectrochemical energy storage devices play a vital role in human life, and the requirements for their sustainability and environmental friendliness have been increasing in recent years. Electropolymerization, as a convenient method for polymer synthesis, has attracted increasing attentions in applications in the field of energy storage and conversion. It is not only commonly employed for the fabrication of various self‐supporting electrodes, but also is one of the most promising preparation strategies for organic electrode materials, internal interlayers within electrodes, functional protective layers, and current collector surface modifications. Previously published works have confirmed that the introduction of electropolymerization can effectively improve the electrochemical performance of various energy storage devices. However, there are still challenges in the universality of the synthesis route, in‐depth understanding of interface chemical behavior, and scaled‐up production. This mini review summarizes the main components in electropolymerization, material synthesis mechanisms, and their application principles in batteries and supercapacitors. Additionally, the current challenges and future development directions of electropolymerization have been discussed, offering some perspectives for further exploration.

Experimental investigation on thermal performance of porous composite phase change storage device under different operating modes and parameters

To promote the transformation from traditional heating to clean heating, the electric heat storage technology is gradually gaining attention. This study prepared a new kind of porous phase change bricks with high heat storage density and thermal conductivity, and constructed a new type of phase change storage device with multi-airflow channels for space heating. Under different operating modes and conditions, a series of experiments were conducted to analyze the heat storage/release performance, energy conversion efficiency and internal temperature distribution. When the heating power increased from 1000 W to 1400 W, the heat storage efficiency increased by 7.3% and the exergy efficiency decreased by 2.6% in Case I (heat storage mode). The rise in outlet wind speed improved the heat output capacity, yet the exergy performance varied in different modes. When the outlet wind speed increased from 0.05 m/s to 0.2 m/s, the heat release efficiency increased by 27.3% in Case II (heat release mode) and 8.3% in Case III-b (simultaneous heat storage and release mode). The exergy efficiency increased by 6.3% in Case II and dropped by 4.6% in Case III-b. In addition, the internal temperature uniformity (Sx) was mainly affected by the distribution of heat sources and airflow.

Understanding the Role of Additives on The Electrochemistry and Performance of Zn Energy Storage Devices

AbstractAs the interest in alternative Li‐based energy storage technologies increased during the last years, zinc emerged as a promising candidate. Despite several advantages over Li, Zn cycling stability is still a major issue. In this article, the use of near‐neutral electrolytes (non‐expensive 2 M ZnSO4) with the addition of different additives (dimethylsulfoxide and tetratethylammonium chloride) is proposed as a solution. The Zn deposition/dissolution electrochemistry has been evaluated and the cycling stability was determined in Zn//Zn symmetric coin‐cells. Hybrid supercapacitors were also assembled and tested in a range of 0.2 V–1.8 V for 2000 cycles, using activated carbon electrodes as cathode and Zn foil as anode. The results show that dimethylsulfoxide strongly inhibits the Zn deposition process, evidenced by a decrease in the cathodic current density, as well as in the dissolution peak. DMSO affects the deposition mechanism, whereas tetratethylammonium chloride reduces the exchange current density, consistent with the adsorption of tetraethylammonium ions on the Zn surface. A synergy between both additives leading to further inhibition of Zn2+ reduction is observed allowing cycling up to 250 hours for Zn//Zn devices. In addition, the performance of hybrid supercapacitors has also improved showing better capacity and extended cycle life.

Switchable Charge Storage Mechanism via in Situ Activation of MXene Enables High Capacitance and Stability in Aqueous Electrolytes.

The need for reliable renewable energy storage devices has become increasingly important. However, the performance of current electrochemical energy storage devices is limited by either low energy or power densities and short lifespans. Herein, we report the synthesis and characterization of multilayer Ti4N3Tx MXene in various aqueous electrolytes. We demonstrate that Ti4N3Tx can be electrochemically activated through continuous cation intercalation over a 10 day period using cyclic voltammetry. A wide operating window of 2 V is maintained throughout activation. After activation, capacitance at 2 mV s-1 increases by 300%, 140%, and 500% in 1 M H2SO4, 1 M MgSO4, and 1 M KOH, respectively, while maintaining ∼600 F g-1 at 2 mV s-1 after 50000 cycles in 1 M H2SO4. This activation process is possibly attributed to the unique morphology of the multilayered material, allowing cation intercalation to increase access to redox-active sites between layers. This work adds to the growing repository of electrochemically stable MXenes reported for aqueous energy storage applications. These findings offer a reliable option for reliable energy storage devices with potential applications in large-scale grid storage and electric vehicles.

In Situ Synthesis of Rare-Earth Hybridized Functional Core-Shell Architectures from Microporous Salt Templates and Capacitance-Adsorption Correlation Mechanisms.

Biochar Porous Carbon (BPC) has become a research hotspot in the fields of energy storage, conversion, catalysis, adsorption, and separation engineering. However, the key problem of pore structure liable to collapse has not yet been addressed effectively. Here, an innovative salt ionic coordination modulation technique is reported to synthesize a new core-shell structure of BPC (Dual-doped porous carbonaceous materials, RHPC3@LaYO3) by the asymmetric load of the f orbital ion, which prevents pore structural collapse. The result shows that the novel asymmetric supercapacitors (ASCs) with an excellent energy density (193.11Wh·kg-1) and capacitance (267.14F·g-1) by assembling the prepared porous BPC carrier and RHPC3@LaYO3, which surpass the typical supercapacitor. In order to elucidate the association between adsorption and capacitance, the adsorption coexistence equation (MACE) is constructed with the aim of providing a comprehensive explanation for the mechanism of single-multilayer adsorption. Furthermore, a specific linkage mechanism is discovered using adsorption/ desorption properties to validate the pros/cons of capacitive properties. These results demonstrate the potential of renewable biomass materials as ASCs, which can provide new ideas for the construction of an evaluation approach for the performance of future efficient multi-reaction energy storage devices.

Recent progress on the thermoelectric effect for electrochemistry

Advances in the mechanisms by which thermoelectric effects influence the performance of electrochemical-based energy conversion and storage devices.

Understanding ion-transfer reactions in silver electrodissolution and electrodeposition from first-principles calculations and experiments.

The electrified aqueous/metal interface is critical in controlling the performance of energy conversion and storage devices, but an atomistic understanding of even basic interfacial electrochemical reactions challenges both experiment and computation. We report a combined simulation and experimental study of (reversible) ion-transfer reactions involved in anodic Ag corrosion/deposition, a model system for interfacial electrochemical processes generating or consuming ions. With the explicit modeling of the electrode potential and a hybrid implicit-explicit solvation model, the density functional theory calculations produce free energy curves predicting thermodynamics, kinetics, partial charge profiles, and reaction trajectories. The calculated (equilibrium) free energy barriers (0.2 eV), and their asymmetries, agree with experimental activation energies (0.4 eV) and transfer coefficients, which were extracted from temperature-dependent voltage-step experiments on Au-supported, Ag-nanocluster substrates. The use of Ag nanoclusters eliminates the convolution of the kinetics of Ag+(aq.) generation and transfer with those of nucleation or etch-pit formation. The results indicate that the barrier is controlled by the bias-dependent competition between partial solvation of the incipient ion, metal-metal bonding, and electrostatic stabilization by image charge, with the latter two factors weakened by stronger positive biases. We also report simulations of the bias-dependence of defect generation relevant to nucleating corrosion by removing an atom from a perfect Ag(100) surface, which is predicted to occur via a vacancy-adatom intermediate. Together, these experiments and calculations provide the first validated, accurate, molecular model of the central steps that govern the rates of important dissolution/deposition reactions broadly relevant across the energy sciences.

Exploring how cation entropy influences electric double layer formation and electrochemical reactivity.

Electric double layers are crucial to energy storage and electrocatalytic device performance. While double layer formation originates in electrostatic interactions, electric double layer properties are governed by a balance of both electrostatic and entropic driving forces. Favorable ion-surface electrostatic interactions attract counterions to charged surfaces to compensate, or "screen," potentials, but the confinement of these same ions from a bulk reservoir to the interface incurs an entropic penalty. Here, we use a dicationic imidazolium ionic liquid and its monovalent analogue to explore how cation valence and entropy influence double layer formation and electrochemical reactivity using CO2 electroreduction as a model reaction. We find that divalent and monovalent cations display similar CO2 reduction kinetics but differ vastly in steady-state reactivity due to rapid electrochemically induced precipitation of insulating dicationic (bi)carbonate films. Using in situ surface-enhanced Raman scattering spectroscopy, we find that potential-dependent cation reorientation occurs at similar potentials between the two ionic liquids, but the introduction of a covalent link in the divalent cation imparts a more ordered double layer structure that favors (bi)carbonate precipitation. In mixed monovalent-divalent electrolytes, we find that the divalent cations dominate interfacial properties by preferentially accumulating at surfaces even at very low relative concentrations. Our findings confirm that ion entropy plays a key role in modulating local electrochemical environments. Furthermore, we highlight how double layer properties are sensitive to the properties of counterions that pay the lowest entropic penalty to accumulate at interfaces. Overall, we illustrate that ion entropy provides a new knob to tune reaction microenvironments and unveil how entropy plays a major role in modulating electrochemical reactivity in mixed ion electrolytes.

Electric field-assisted laser ablation fabrication and assembly of zinc oxide/carbon nanocomposites into hierarchical structures for supercapacitor electrodes.

One of the major challenges in the field of electrochemical energy storage device performance improvement is the development of suitable synthetic materials for electrodes that can provide high power and high energy density features combined with their long-term stability. Here, we have developed a novel two-step approach based on DC glow discharge plasma pre-treatment of a carbon cloth substrate followed by electric field-assisted laser ablation for the synthesis of ZnO/C nanocomposites in a liquid and their simultaneous assembly into hierarchically organized nanostructures onto the pre-processed carbon cloth to produce a supercapacitor electrode. To form such nanostructures, a processed carbon cloth was included in the electrical circuit as a cathode during laser ablation of zinc in water, while a zinc target served as an anode. A series of studies have been performed to explore the structure, morphology, composition and electrochemical characteristics of the synthesized ZnO/C nanocomposites. Application of the external field provided additional possibilities for tuning the particle morphology. The parameters of the obtained nanostructures were shown to depend on the direction of the applied electric field and liquid composition. SEM studies revealed a nanoflower-like morphology of the prepared nanomaterial having potential in supercapacitor applications due to a large surface area. The ZnO/C nanoflowers, deposited onto a carbon cloth substrate, were tested for energy storage by cyclic voltammetry (CV) and galvanostatic charge-discharge (GCD) analysis. The results showed a pseudocapacitor behavior with a maximum specific capacitance of about 3045 F g-1 (at a scan rate of 1 mV s-1). These results demonstrate a promising storage efficiency of the synthesized ZnO/C nanocomposite as a material for supercapacitors.

Delay-D: Research on the Lifespan and Performance of Storage Devices in Unmanned Aerial Vehicles

Despite the technological achievements of unmanned aerial vehicles (UAVs) growing in academia and industry, there is a lack of studies on the storage devices in UAVs. However, this is an important aspect because the storage devices in UAVs have a limited lifespan and performance and are rarely replaced due to a system-on-chip architecture. In this paper, we study how UAVs impact the lifespan and performance of the underlying storage device while capturing images during overflight. We also propose a new lifespan and performance-saving mechanism, called Delay-D, which is designed at the kernel level to efficiently utilize the features of NAND flash-based storage devices. To confirm the effectiveness of Delay-D, we implement a simulator that replays realistic write patterns on UAVs and evaluate quantitative experiments in two different experimental environments. In our evaluation, Delay-D demonstrates the dramatic extension possibility of the lifespan by reducing the number of extra writes inside the storage device and improving the overall performance by up to 2.1× on the commercial NVMe SSD.