Enhanced Storage Performance Research Articles

Enhanced storage performance of a low-cost hard carbon derived from biomass

Hard Carbon is the most widely used negative electrode material for sodium-ion batteries today. Achieving high storage capacity and increasing the plateau capacity, as opposed to the sloping profile, are crucial for enhancing energy density of the full cells. While several publications address the synthesis of hard carbon, the economic viability for commercial scale-up hinges on the choice of precursors. In this study, we report the electrochemical properties of hard carbon derived from two biomass precursors, sugarcane waste (bagasse) and corn waste, and compare their performances with commercially available hard carbon. The hard carbon derived from bagasse delivers a capacity of 307 mAh/g at C/10 rate and retains approximately 234 mAh/g at 3C discharge rate. We integrate surface area, pore size distribution, Raman spectroscopy, small-angle X-ray and neutron scattering data to elucidate the sodium storage mechanism in these hard carbon samples. Correlated graphitic domains with hexagonal ordering along with fractal like agglomeration of the nanosheets are quantified. The high plateau capacity of the bagasse-derived hard carbon is attributed to the characteristic morphology and size distribution of the nanosheets and their nature of agglomeration.

Nano-crystalline Fe3V3O8 material as an efficient advanced anode for energy storage applications

The sodium-ion battery (SIB) is a rapidly developing electrochemically rechargeable storage device and a direct substitute for Li-ion batteries. Therefore, identifying novel materials for sodium-ion storage applications is important. Efficient electrodes are particularly desirable for enhancing storage performance in battery applications. In this study, we fabricated a novel Fe3V3O8 (FVO) anode material for Na/Li-ion storage using hydrothermal technology for the first time. The electrochemical results indicated that the initial sodiation capacity of the FVO anode is as high as 805 mA h g−1 at 100 mA g−1, and a reversible sodiation capacity of 540 mA h g−1 is maintained over 200 cycles at 500 mA g−1, which is more than 1.8 times the commercial hard carbon of ∼300 mA h g−1. In addition, the oxidation states of the chemical compound and the corresponding sodium reaction mechanism are predicted using X-ray absorption spectroscopy (XAS), X-ray photoelectron spectroscopy (XPS), and in-situ/ex-situ X-ray diffraction (XRD) analysis. Overall, the FVO material exhibited significantly higher electrochemical performance, demonstrating promising suitability for sodium-ion storage.

Hydrothermal Synthesis of (NH4)2V7O16/Reduced Graphene Oxide Composite with Enhanced Storage Performance for Aqueous Lithium‐Ion Batteries

Herein, a facile hydrothermal method is utilized to prepare a (NH4)2V7O16/reduced graphene oxide (rGO) composite. In an aqueous electrolyte, the obtained (NH4)2V7O16/rGO exhibits superior lithium storage characteristics compared to pure (NH4)2V7O16 in both the three‐electrode configuration and full cell. This improvement can be ascribed to the synergistic effects of incorporation of defective oxygen and rGO modification. The present study proposes a feasible strategy for enhancing the electrochemical properties of (NH4)2V7O16 and demonstrates the potential of the (NH4)2V7O16/rGO composite for aqueous rechargeable lithium‐ion batteries.

Modeling hydrogen storage at room temperature: Adsorbent materials for boosting pressure reduction in compressed H2 tanks

Energy storage systems are required for an efficient integration of renewables into the grid to achieve a net zero energy system. Hydrogen compressed at 700 bar, is one of the key energy storage technologies. This study evaluates the effectiveness of solid-state hydrogen storage, particularly physisorption in porous materials, to enhance storage performance and safety at room temperature by reducing the operating tank pressure. We model dynamically the entire storage system, comparing adsorbent materials to traditional compression in terms of maximum tank pressure and round-trip storage efficiency. Different energy system applications with varied cycle frequencies and discharge durations were examined. Results indicate that porous material-based systems exhibit higher efficiency for long-duration energy storage services than the compressed hydrogen. Notably, bulk density plays a pivotal role in storage performance. For instance, IRMOF-1 with a bulk density of 500 kg/m3, shows a 70 % pressure reduction compared to compressed hydrogen systems. In contrast, when its bulk density is reduced to 130 kg/m3, the maximum tank pressure is even 30 % higher than the compressed tank. We emphasize the need for comprehensive material characterization, highlighting the significance of parameters like bulk density for determining the most performing hydrogen adsorbent material in terms of maximum tank pressure and efficiency. As general outcome, the best performing material depends on the specific target or system requirements, such as pressure, volume, cost, or weight.

Fully Biodegradable Packaging Films for Fresh Food Storage Based on Oil-Infused Bacterial Cellulose.

Fully biodegradable packaging materials are demanded to resolve the issue of plastic pollution. However, the fresh food storage performance of biodegradable materials is generally much lower than that of plastics due to their high permeability, microbial friendliness, and limited stretchability and transparency. Here a biodegradable packaging material is reported with high fresh food storage performance based on an oil-infused bacterial cellulose (OBC) porous film. The oil infusion significantly improved cellulose's food-keeping performance by reducing its gas permeability, increasing its stretchability and transparency, and enabling the active release of green vapor-phase preservative molecules, while maintaining its intrinsically high degradability. Strawberries stored in a container with the OBC lid at 23°C after 5 days exhibited a moldy rate of 0%, in contrast to the 100% moldy rate of those stored by poly(ethylene). Enhanced storage performance is also obtained on tomatoes, pork, and shrimp. The OBC film is naturally degraded after being buried in wet soil at 30°C for 9 days, identical to the degradation rate of bacterial cellulose. The liquid seal strategy broadly applies to different celluloses, providing a general option for developing cellulose-based biodegradable packaging materials.

Research on Secure Storage Technology of Spatiotemporal Big Data Based on Blockchain

With the popularity of spatiotemporal big data applications, more and more sensitive data are generated by users, and the sharing and secure storage of spatiotemporal big data are faced with many challenges. In response to these challenges, the present paper puts forward a new technology called CSSoB (Classified Secure Storage Technology over Blockchain) that leverages blockchain technology to enable classified secure storage of spatiotemporal big data. This paper introduces a twofold approach to tackle challenges associated with spatiotemporal big data. First, the paper proposes a strategy to fragment and distribute space–time big data while enabling both encryption and nonencryption operations based on different data types. The sharing of sensitive data is enabled via smart contract technology. Second, CSSoB’s single-node storage performance was assessed under local and local area network (LAN) conditions, and results indicate that the read performance of CSSoB surpasses its write performance. In addition, read and write performance were observed to increase significantly as the file size increased. Finally, the transactions per second (TPS) of CSSoB and the Hadoop Distributed File System (HDFS) were compared under varying thread numbers. In particular, when the thread number was set to 100, CSSoB demonstrated a TPS improvement of 7.8% in comparison with HDFS. Given the remarkable performance of CSSoB, its adoption can not only enhance storage performance, but also improve storage security to a great extent. Moreover, the fragmentation processing technology employed in this study enables secure storage and rapid data querying while greatly improving spatiotemporal data processing capabilities.

Underground hydrogen storage to balance seasonal variations in energy demand: Impact of well configuration on storage performance in deep saline aquifers

Grid-scale underground hydrogen storage (UHS) is essential for the decarbonization of energy supply systems on the path towards a zero-emissions future. This study presents the feasibility of UHS in an actual saline aquifer with a typical dome-shaped anticline structure to balance the potential seasonal mismatches between energy supply and demand in the UK domestic heating sector. As a main requirement for UHS in saline aquifers, we investigate the role of well configuration design in enhancing storage performance in the selected site via numerical simulation. The results demonstrate that the efficiency of cyclic hydrogen recovery can reach around 70% in the short term without the need for upfront cushion gas injection. Storage capacity and deliverability increase in successive storage cycles for all scenarios, with the co-production of water from the aquifer having a minimal impact on the efficiency of hydrogen recovery. Storage capacity and deliverability also increase when additional wells are added to the storage site; however, the distance between wells can strongly influence this effect. For optimum well spacing in a multi-well storage scenario within a dome-shaped anticline structure, it is essential to attain an efficient balance between well pressure interference effects at short well distances and the gas uprising phenomenon at large distances. Overall, the findings obtained and the approach described can provide effective technical guidelines pertaining to the design and optimization of hydrogen storage operations in deep saline aquifers.

Design of a latent heat thermal energy storage system under simultaneous charging and discharging for solar domestic hot water applications

Latent heat thermal energy storage (LHTES) systems using phase change materials (PCMs) have appeared as promising solutions for energy storage when harnessing renewable energy sources in a wide range of engineering applications. The present study focuses on the design of horizontal shell-and-tube PCM-based LHTES systems capable of simultaneous charging and discharging in solar domestic hot water (SDHW) applications. Two scenarios are investigated: (i) initially fully charged, and (ii) initially fully discharged LHTES systems, in both cases with a 30-min charge/discharge time interval. Configurations with key geometrical design variations are considered to identify the best radial and tangential positions of the heat transfer fluid (HTF) tubes inside the shell that enhance storage performance against the following criteria: (i) gained and released thermal power, and (ii) total gained and released energy per unit mass of PCM. The distance between the hot and cold HTF tubes was maintained constant and an LHTES with horizontally aligned HTF tubes was selected as a baseline case. The findings showed that tangential displacement had a considerable impact on the performance of the system, while the effect of radial displacement was marginal. A design with displacements of ¼ tube diameter and 90° in the radial and tangential positions of the HTF tubes, respectively, had promising performance in both considered scenarios. In comparison to the baseline case, which had the hot and cold tubes positioned horizontally, and symmetrically on the shell's central plane, this configuration demonstrated a 103.02% enhancement in energy delivery in the fully discharged and a 2% enhancement in the fully charged scenario, respectively.

Biowaste-derived graphitic carbon interfaced TiO2 as anode for lithium-ion battery

Facile application of carbon derived from natural resources and its composites with transition metal oxides for energy storage has attracted great interest. The synthesis procedure of these hybrid composites is complicated and requires various toxic chemicals. To address the above issues in the present investigation, we synthesized mentha aquatica (MA) biowaste-derived graphitic carbon titanium dioxide (TMGCs) composite through a facile biogenic single precursor approach. The MA leaves extract was used to synthesize TiO2 (TDO) nanoparticles, and MGCs was obtained from the remaining residue. The structural integrity of the composite is identified using analytical tools. The formed TMGCs composite, when used as a lithium-ion battery (LIB) anode, reveals improved Li+ ion storage capabilities than those of pristine TDO and MGCs anodes. The TMGCs hybrid composite anode shows an initial discharge capacity of 597 mAh g–1 at a current density of 100 mA g–1 with excellent restoration (∼ 100% at 0.1 A g–1) and retention (94% at 0.5 A g–1) capabilities at the associated applied current rates. Moreover, the hybrid composite anode reveals excellent coulombic efficiency (η = 103, ∼ 102, and 100% at 0.5, 2.0, and 5.0 A g–1, respectively) even after long-term discharge-charge stabilities over 1000 cycles. The enhanced storage performance of the TMGCs composite can be attributed to the improved conductivity and efficient Li+ ion transport, which is a result of the high specific surface area associated with the mesopores TiO2 structure and the warped carbon sheets.

A novel compression-assisted energy storage heat transformer for low-grade renewable energy utilization

Thermal energy storage is a promising method to balance the timing mismatch between the intermittent energy sources and time-variable user loads but cannot address the low-grade issue, which results in the underutilization of low-temperature renewable energy. An absorption-based energy storage heat transformer (ESHT) can achieve temperature upgrading with satisfactory storage performance. To further improve the system performance, a novel compression-assisted ESHT (CESHT) is proposed. The dynamic characteristics of the basic ESHT and CESHT cycles are analyzed and compared. Then, the effects of heat output, heat input, and heat sink temperatures on the cycle performance are investigated. Results show that significant enhancements are achieved by the CESHT cycle for both energy storage performance and temperature upgrading ability. With auxiliary compression, the temperature lift is increased from 30 °C to 65 °C, and the required input temperature is decreased from 60 °C to 45 °C. Moreover, the performance indexes are greatly improved, e.g., the energy storage efficiency, energy storage density, and exergy efficiency are respectively increased from 0.24 to 0.43, from 35.2 kWh/m3 to 282.7 kWh/m3, and from 0.32 to 0.54 with a temperature lift of 30 °C. The proposed cycle demonstrates the advantages of enhanced storage performance and large temperature lift.

Flexible hydrogel compound of V2O5/GO/PVA for enhancing mechanical and zinc storage performances

A highly flexible hydrogel cathode applied in rechargeable aqueous zinc-ion batteries (ZIBs) fabricated by polyvinyl alcohol (PVA), vanadium pentoxide (V2O5) and graphene oxide (GO) has been successfully synthesized by repeated freeze-thaw method. The V2O5/GO hydrogel (VOGH) presented complex 3D cross-linking system and excellent flexibility through hydrogen bonding and inorganic nanosheets reinforcement. The mechanical and electrochemical properties of VOGH are balanced and achieved by adjusting the content of GO (5%), V2O5 (30%), PVA (25%) and water (40%) of the total mass, respectively. From the electrochemical result, the flexible hydrogel cathode displayed a high capacity (240.5 mA h g–1) and a good cyclic stability after 200 cycles at 1 A g–1. Moreover, the electrochemical kinetics exhibite the capacitive control process, which confirm the excellent ion transport to enhance storage performance of ZIBs. The soft package ZIBs using VOGH as cathode and Zn foil as anode display good cycle performance (191.7 mA h g–1 at 1 A g–1 after 1000 cycles) and provide stable power supply at different bending angles.

Super Flexible Cathode Material with 3D Cross‐Linking System Based on Polyvinyl Alcohol Hydrogel for Boosting Aqueous Zinc Ion Batteries

AbstractA flexible hydrogel cathode constructed by polyvinyl alcohol, MnO2and graphene was successfully prepared through repeated freeze‐thaw method, which formed complex 3D cross‐linking system with hydrogen bonding and inorganic particle reinforcement. The superior mechanical and electrochemical performance were balanced and obtained by controlling the content of MnO2(30 %) and H2O (10 %) of the total mass, respectively. As a result, this flexible hydrogel cathode delivered a high capacity of 164.2 mA h g−1at 1 A g−1and an outstanding cyclic stability after 500 cycles at 1 A g−1. Furthermore, hydrogel matrix and graphene conductive network could effectively prevent volume expansion and pulverization of MnO2nanoparticles. And the electrochemical kinetic revealed that the main process was capacitive control, which confirmed the excellent ion transport to enhance storage performance of ZIBs. The soft package ZIBs provided stable power supply at different bending angles.

Nitrogen-Doped Porous MXene (Ti3C2) for Flexible Supercapacitors with Enhanced Storage Performance.

Flexible supercapacitors (FSCs) are limited in flexible electronics applications due to their low energy density. Therefore, developing electrode materials with high energy density, high electrochemical activity, and remarkable flexibility is challenging. Herein, we designed nitrogen-doped porous MXene (N-MXene), using melamine-formaldehyde (MF) microspheres as a template and nitrogen source. We combined it with an electrospinning process to produce a highly flexible nitrogen-doped porous MXene nanofiber (N-MXene-F) as a self-supporting electrode material and assembled it into a symmetrical supercapacitor (SSC). On the one hand, the interconnected mesh structure allows the electrolyte to penetrate the porous network to fully infiltrate the material surface, shortening the ion transport channels; on the other hand, the uniform nitrogen doping enhances the pseudocapacitive performance. As a result, the as-assembled SSC exhibited excellent electrochemical performance and excellent long-term durability, achieving an energy density of 12.78 Wh kg−1 at a power density of 1080 W kg−1, with long-term cycling stability up to 5000 cycles. This work demonstrates the impact of structural design and atomic doping on the electrochemical performance of MXene and opens up an exciting possibility for the fabrication of highly FSCs.

In situ incorporation of highly dispersed nickel and vanadium trioxide nanoparticles in nanoporous carbon for the hydrogen storage performance enhancement of magnesium hydride

Slow hydrogen absorption-desorption kinetics and high thermal stability hinder the industrial application of Mg/MgH2 systems. In order to overcome these drawbacks, the in situ incorporation of highly dispersed nickel and vanadium trioxide nanoparticles in nanoporous carbon ((Ni-V2O3)@C) was introduced to enhance the hydrogen storage performance of Mg/MgH2. It was found that the 10 wt% (Ni-V2O3)@C-containing sample demonstrated excellent hydrogen storage performance. The 10 wt% (Ni-V2O3)@C-containing sample could uptake hydrogen at room temperature, and its initial hydrogenation temperature was reduced by 100 °C as compared to that of pristine MgH2. Moreover, this system could absorb 5.50 wt% of H2 at 25 °C and release 6.05 wt% of H2 at 275 °C in 10 min. In addition, the hydrogenation and dehydrogenation activation energies of the 10 wt% (Ni-V2O3)@C-containing sample were calculated as 42.1 kJ·mol−1 and 84.6 kJ·mol−1, respectively, which were 46.8 kJ·mol−1 and 51.6 kJ·mol−1 lower than those of pristine MgH2, respectively. Mechanism analysis results revealed that V2O3 was partially converted into VO during milling with MgH2, and Ni reacted with Mg to form in situ Mg2Ni after the first dehydrogenation. The in situ Mg2Ni/Mg2NiH4 coating around Mg/MgH2 acted as a “hydrogen pump” to drive hydrogen diffusion and dissociation, and the presence of C inhibited the agglomeration of Mg/MgH2 particles. Therefore, the addition of (Ni-V2O3)@C was found to be a good strategy to improve the hydrogen storage performance of MgH2.

Hydrogen storage performance enhancement and bandgap opening of M-Decorated (M = Li, Na and K) III4–V4 monolayer by fluorine functionalization

The effects of fluorine functionalization on the hydrogen storage capability of alkaline decorated III4–V4 monolayers is studied. This structure can store up to two hydrogen molecules per alkaline atom. Here, we demonstrate that functionalizing alkaline decorated monolayer with a high electronegative element of fluorine can significantly enhance both binding energy and the maximum number of the stored hydrogen molecules. In this regard, the hydrogen molecule storage capability is notably improved from two to four and when absolute binding is considered. In addition, F-functionalization of M-decorated III4–V4 can demonstrate bandgap opening effect, introduce semiconducting characteristics and forming a new two-dimensional semiconductor structure. The bandgap for Li–Al4P4–F is 1.23 eV which is very close to the solar peak. The resulted bandgap in the M–III4–V4-F structure is even significantly larger than that of pristine III4–V4 monolayer. The binding of the hydrogen molecule to the alkaline atom is also improved from 0.114 to 0.272 eV by the fluorine functionalization.

Enhancing storage performance of P2-type Na2/3Fe1/2Mn1/2O2 cathode materials by Al2O3 coating

The P2-type Na2/3Fe1/2Mn1/2O2 materials were synthesized by an ultrasonic spray pyrolysis followed by solid-state sintering method. The structures, morphologies and electrochemical performances of Na2/3Fe1/2Mn1/2O2 materials were characterized thoroughly by means of X-ray diffractometer, scanning electron microscope and electrochemical charge/discharge instruments. Moreover, a thin layer of Al2O3, which was formed on the surface of Na2/3Fe1/2Mn1/2O2, can enhance the storage performance by preventing the formation of Na2CO3·H2O, which is believed to enhance the electrochemical performances of Na2/3Fe1/2Mn1/2O2 materials. This facile surface modification method may pave a way to synthesize advanced cathode materials for sodium-ion batteries.

Dielectric property and energy storage performance enhancement for iron niobium based tungsten bronze ceramic.

Ceramic dielectric capacitors have attracted increasing interest due to their wide applications in pulsed power electronic systems. Nevertheless, synchronously achieving the high energy storage density, high energy storage efficiency and good thermal stability in dielectric ceramics is still a great challenge. Herein, lead free Sr3SmNa2Fe0.5Nb9.5O30 (SSNFN) ceramic with tetragonal tungsten bronze structure was synthesized and characterized, high total energy storage density (2.1 J cm-3), recoverable energy storage density (1.7 J cm-3), energy storage efficiency (80%) and good thermal stability are obtained simultaneously in the compound, due to the contribution of high maximum polarization (P max), low remanent polarization (P r) and large breakdown strength (E b). The high P max is related with the intrinsic characteristic of Sr4Na2Nb10O30 (SNN) based system, while the small P r and good thermal stability stem from the significantly enhanced relaxor behavior. In addition, the large E b originates from the improved microstructure with fewer defects and decreased average grain size, and the reduction of electrical heterogeneity compared with SNN. The capacitive performance obtained in this work points out the great potential of tungsten bronze ceramic designed for energy storage applications and pave a feasible way to develop novel lead-free dielectric capacitors.

Thermal storage performance enhancement and regulation mechanism of KNO3-SWCNT based composite phase change materials

In this paper, the single walled carbon nanotube (SWCNT) was doped into KNO3 to prepare the KNO3-SWCNT based composite phase change material (CPCM), and its microstructure was established. The methods of thermal storage performance prediction, enhancement and regulation for CPCM were developed by means of molecular dynamics (MD) simulation combined with experiments, and the microscopic mechanism was revealed at nanoscale. It was found that when SWCNT mass fraction increases from 0 to 4.43 wt. % and 8.48 wt. %, the thermal conductivity is significantly increased, with an average increase of 2.26% and 28.01%, respectively, the specific heat capacity is effectively enhanced by 11.72% and 16.55%, respectively, and the melting enthalpy is decreased by 32.31% and 45.19%, respectively. The SEM experiments are carried out to characterize the microstructure of CPCM, inspired by the ordered distribution of SWCNT, the formation of thermal link and nano layer in CPCM can be promoted, so as to improve the thermal storage performance of CPCM; the interface regulation was achieved by the surface positive modification of SWCNT, which can effectively enhance the potential energy interaction between the atoms, thus the thermal conductivity of CPCM is enhanced, with an average enhancement of 21.21%.

Enhanced Storage Performance of PANI and PANI/Graphene Composites Synthesized in Protic Ionic Liquids.

Polyaniline (PANI) was synthesized using oxidative polymerization in a mixture of water with pyrrolidinium hydrogen sulfate [Pyrr][HSO4], which is a protic ionic liquid PIL. The obtained PANI (PANI/PIL) was compared with conventional PANI (PANI/HCl and PANI/HSO4) in terms of their morphological, structural, and storage properties. The results demonstrate that the addition of this PIL to a polymerization medium leads to a fiber-like morphology, instead of a spherical-like morphology, of PANI/HSO4 or an agglomerated morphology of PANI/HCl. In addition, PAN/PIL exhibits an improvement of the charge transfer kinetic and storage capability in H2SO4 1 mol·L−1, compared to PANI/HCl. The combination of PANI/PIL and graphene oxide (GO), on the other hand, was investigated by optimizing the PANI/GO weight ratio to achieve the nanocomposite material with the best performance. Our results indicate that the PANI/PIL/GO containing 16 wt% of GO material exhibits a high performance and stability (223 F·g−1 at 10 A·g−1 in H2SO4 1 mol·L−1, 4.9 Wh·Kg−1, and 3700 W·Kg−1 @ 10 A·g−1). The obtained results highlight the beneficial role of PIL in building PANI and PANI/GO nanocomposites with excellent performances for supercapacitor applications.

Role of Additives in Electrochemical Deposition of Ternary Metal Oxide Microspheres for Supercapacitor Applications.

A simple two-step approach has been employed to synthesize a cobalt–nickel–copper ternary metal oxide, involving electrochemical precipitation/deposition followed by calcination. The ternary metal hydroxide gets precipitated/deposited from a nitrate bath at the cathode in the catholyte chamber of a two-compartment diaphragm cell at room temperature having a pH ≈ 3. The microstructure of the ternary hydroxides was modified in situ by two different surfactants such as cetyltrimethylammonium bromide and dodecyltrimethylammonium bromide in the bath aiming for enhanced storage performance in the electrochemical devices. The effect of the surfactant produces a transition from microspheres to nanosheets, and the effect of micelle concentration produces nanospheres at a higher ion concentration. The ternary hydroxides were calcined at 300 °C to obtain the desired ternary mixed oxide materials as the electrode for hybrid supercapacitors. X-ray diffraction analysis confirmed the formation of the ternary metal oxide product. The scanning electron microscopy images associated with energy-dispersive analysis suggest the formation of a nanostructured porous composite. Ternary metal oxide in the absence and presence of a surfactant served as the cathode and activated carbon served as the anode for supercapacitor application. DTAB-added metal oxide showed 95.1% capacitance retention after 1000 cycles, achieving 188 F/g at a current density of 0.1 A/g, and thereafter stable until 5000 cycles, inferring that more transition metals in the oxide along with suitable surfactants at an appropriate micellar concentration may be better for redox reactions and achieving higher electrical conductivity and smaller charge transfer resistance. The role of various metal cations and surfactants as additives in the electrolytic bath has been discussed.