Storage Capacity Research Articles

Numerical Investigation of Transmission and Sealing Characteristics of Salt Rock, Limestone, and Sandstone for Hydrogen Underground Energy Storage in Ontario, Canada

With the accelerating global transition to clean energy, underground hydrogen storage (UHS) has gained significant attention as a flexible and renewable energy storage technology. Ontario, Canada, as a pioneer in energy transition, offers substantial underground storage potential, with its geological conditions of salt, limestone, and sandstone providing diverse options for hydrogen storage. However, the hydrogen transport characteristics of different rock media significantly affect the feasibility and safety of energy storage projects, warranting in-depth research. This study simulates the hydrogen flow and transport characteristics in typical energy storage digital rock core models (salt rock, limestone, and sandstone) from Ontario using the improved quartet structure generation set (I-QSGS) and the lattice Boltzmann method (LBM). The study systematically investigates the distribution of flow velocity fields, directional characteristics, and permeability differences, covering the impact of hydraulic changes on storage capacity and the mesoscopic flow behavior of hydrogen in porous media. The results show that salt rock, due to its dense structure, has the lowest permeability and airtightness, with extremely low hydrogen transport velocity that is minimally affected by pressure differences. The microfracture structure of limestone provides uneven transport pathways, exhibiting moderate permeability and fracture-dominated transport characteristics. Sandstone, with its higher porosity and good connectivity, has a significantly higher transport rate compared to the other two media, showing local high-velocity preferential flow paths. Directional analysis reveals that salt rock and sandstone exhibit significant anisotropy, while limestone’s transport characteristics are more uniform. Based on these findings, salt rock, with its superior sealing ability, demonstrates the best hydrogen storage performance, while limestone and sandstone also exhibit potential for storage under specific conditions, though further optimization and validation are required. This study provides a theoretical basis for site selection and operational parameter optimization for underground hydrogen storage in Ontario and offers valuable insights for energy storage projects in similar geological settings globally.

Activating Organic Electrode for Zinc Batteries via Adjusting Solvation Structure of Zn Ions.

Zinc-organic batteries, combining the low cost and high capacity of Zn anodes with the tunable and sustainable properties of organic cathodes, have garnered significant attention. Herein, we present a zinc-organic battery featuring a poly(benzoquinonyl sulfide) (PBQS) cathode, a Zn anode, and anN,N-dimethylformamide (DMF)-based electrolyte, which delivers a high capacity (200 mAh g-1), excellent rate capability, and an ultra-long cycle life (10,000 cycles) when tested with a low PBQS loading (2 mg cm-2). The charge storage mechanism in the PBQS cathode involves solvated Zn2+ adsorption and consequent Zn2+ coordination with PBQS companied by de-solvation process, as confirmed by in-situ FT-IR analysis. However, sluggish Zn2+ de-solvation leads to a loss of Zn2+ coordination capacity when tested with higher PBQS loading (8 mg cm-2) even at a low current density of 0.2 A g-1. Remarkably, the addition of 2% H2O to the DMF electrolyte incorporates 0.24 H2O into the primary solvation sheath of Zn2+, significantly facilitating the de-solvation process. As a result, the PBQS cathode (8 mg cm-2) retains its Zn2+ storage capacity when using the modified electrolyte. This approach offers a new strategy for improving the rate performance of organic electrodes, complementing existing conductivity enhancements.

Stable Na+ Ion Storage via Dual Active Sites Utilization in Covalent Organic Framework-Carbon Nanotube Composite.

Redox-active covalent organic frameworks (COFs) with metal binding sites are increasingly recognized for developing cost-effective, eco-friendly organic electrodes in rechargeable energy storage devices. Here, we report a microwave-assisted synthesis and characterization of a triazine-based polyimide COF that features dual redox-active sites (-C=O from pyromellitic and -C=N- from triazine) and COF@CNT nanocomposites (COF@CNT-X, where X=10, 30, and 50 wt % of NH2-MWCNT) formed through covalent linking with amino-functionalized multiwalled carbon nanotubes. These composites are evaluated as cathode materials for the sodium-ion batteries (SIBs). The amine functionalization renders the covalent bond between COF and CNT, improving electronic conductivity, structural rigidity, and long-term stability. The interfacial growth of COF layers on CNTs increases accessible redox-active sites, enhancing sodium diffusion kinetics during sodiation/desodiation. The COF@CNT-50 composite exhibits outstanding Na+ ion storage performance (reversible capacity of 164.3 mAh g-1 at 25 mA g-1) and excellent stability over 1000 cycles at ambient temperature. At elevated temperature (65 °C), it also maintains good capacity and cycle stability. Ex situ XPS analysis confirms the importance of dual active sites in the Na+ diffusion mechanism. Density functional theory (DFT) calculations reveal insights into Na+ binding sites and corresponding binding energies into COF structure, elucidating the experimental storage capacity and voltage profile.

LyDRL: Lyapunov-guided Deep Reinforcement Learning for Stable Task offloading in Connected Autonomous Vehicles

Task offloading is recognized as a promising approach to enhance the computational performance of Connected Autonomous Vehicles (CAVs). Some applications of CAVs, such as metaverse applications, require substantial resources, posing significant challenges to CAVs with limited computing and storage capacities. CAVs can offload resource-intensive applications to the vehicular edge computing (VEC) server, which has strong computing capabilities. To fully utilize the resources in the CAV system, partial offloading is employed. However, the local computing resources are limited for continuously generated partial offloading tasks. This results in many partially locally executed tasks experiencing long processing times or being discarded, which is detrimental to delay-sensitive tasks on CAVs. This paper proposes Lyapunov function guided reinforcement learning for the CAVs task offloading computational framework, LyDRL. Specifically, LyDRL first uses the Lyapunov function to transform the long-term objective optimization problem into subproblems determined at each time slot. In each time slot, deep reinforcement learning is used to obtain the optimal task offloading decision while satisfying the constraints. Simulation results show that compared with existing algorithms, the proposed strategy can ensure the stability of the CAVs system and achieve the lowest system overhead.

Nanofluids in Thermal Energy Storage Systems: A Comprehensive Review

Nanofluids, which consist of nanosized particles dispersed in a base fluid, represent a promising solution to improve the performance of thermal energy storage systems. This review offers a comprehensive overview of nanofluids and their applications in thermal energy storage systems, discussing their thermal properties, heat transfer mechanisms, synthesis techniques, and application in latent heat storage systems. Various types of nanofluids are examined, including metal oxide, carbon-based, and metallic nanofluids, highlighting their effects on thermal conductivity, latent heat and the phase change temperature. A review of experimental and numerical studies showcases the performance of thermal energy storage systems incorporating nanofluids and the factors influencing their thermophysical characteristics and energy storage capacity. Finally, the key findings of current research are summarized, as well as the challenges and the potential future directions in nanofluid-based thermal energy storage systems research, emphasizing the need to optimize nanoparticle concentration and long-term durability.

Combined feature of enhanced stability and multi-level switching observed in TiN/Ta2O5/Ag-NPs/ITO/PET structure

Both stability and multi-level switching are crucial performance aspects for resistive random-access memory (RRAM), each playing a significant role in improving overall device performance. In this study, we successfully integrate these two features into a single RRAM configuration by embedding Ag-nanoparticles (Ag-NPs) into the TiN/Ta2O5/ITO structure. The device exhibits substantially lower switching voltages, a larger switching ratio, and multi-level switching phenomena compared to many other nanoparticle-embedded devices. We attribute it to the embedded Ag-NPs effectively switching the mechanism of conductive filaments and the controlled distribution of Ag-NPs facilitates the occurrence of multi-level switching. Additionally, the fabricated structure demonstrated an impressive optical transmittance of nearly 85%. Undoubtedly, this combined feature of RRAM not only enhances stability but also enables multi-level switching, thereby demonstrating an approach to fabricating versatile and practical electronic devices aimed at boosting storage capacity and speed.

Coordinated operation of pumped hydro energy storage with reversible pump turbine and co-located battery energy storage system

Abstract This publication examines the coordinated operation of pumped hydro energy storage and battery energy storage systems to improve profitability. While pumped hydro energy storages offer high storage capacity but have slower response times, battery energy storage systems have lower capacity but faster response times. A hybrid system combining both can thus harness synergies. A mixed-integer linear programming model was developed to depict the coordinated use of both systems in the German market. The proposed approach is also applicable to other regional markets where energy and balancing services are traded in a similar manner. In this model, the pumped hydro energy storage operates in the spot market and provides automatic Frequency Restoration Reserve, while the battery energy storage systems supplies Frequency Containment Reserve. The model takes into account the costs caused by degradation effects in both storage types. The results show a 10.05 % increase in revenue through coordination compared to the independent operation of both storage systems. This added value can be achieved through more efficient use of the power capacity, particularly that of the battery energy storage systems, in coordinated operation.

Critical review on the derivative of graphene with binary metal oxide-based nanocomposites for high-performance supercapacitor electrodes

Abstract Supercapacitors, owing to their high power density and rapid charge–discharge capabilities, have gained significant attention as energy storage devices in various applications. In the context of electrochemical supercapacitors, this article provides a comprehensive review of the production and electrochemical performance of binary metal oxide (BMO) and reduced graphene oxide (rGO) composite materials. The synthesis processes and synergistic benefits of BMO–rGO composites, with an emphasis on how they perform better than separate parts in terms of specific capacitance and cycle stability, are discussed. The potential of BMO–rGO composites as high-performance electrode materials for supercapacitors is highlighted in this research. In the context of electrochemical supercapacitors, this work provides a comprehensive review of the production and electrochemical performance of binary transition metal oxide (TMO) and rGO composite materials. Composite materials with enhanced electrochemical characteristics that are appropriate for supercapacitor applications are the primary novelty, which is the synergistic combination of rGO with a variety of TMOs. Compared to individual TMOs or other carbonaceous materials, these composites demonstrate enhanced specific capacitance, energy density, power density, cyclic stability, and rate capability. The synthesis processes and synergistic benefits of BMO–rGO composites are discussed, with an emphasis on their superior performance in specific capacitance and cycle stability compared to individual components. This research highlights the potential of BMO–rGO composites as high-performance electrode materials for supercapacitors, showcasing their enhanced specific capacitance, improved charge storage capacity, increased power density, excellent cycling stability, and overall durability even after numerous charge–discharge cycles.

Bamboo–PCM: Comparative Analysis of Phase Change Material-Impregnated Dendrocalamus giganteus Culm Behavior Exposed to Thermal Variation in Wind Tunnel Assay

The construction industry’s pursuit of eco-friendly materials has sparked interest in bamboo, a renewable resource with exceptional physical and mechanical properties. This study analyzed the integration of Dendrocalamus giganteus bamboo with phase change materials (PCMs) to enhance thermal energy storage in building applications, aiming to improve temperature regulation and reduce energy consumption for climate control. The study compared the performance of bamboo impregnated with an industrial PCM or coconut oil, used in conjunction with a polyurethane resin (PU) coating treatment, assessing their thermal regulation performance against traditional building materials such as ceramic tiles, fiber cement, and metal sheets. From an anatomical perspective, the pores within bamboo culms offered ample space for PCM storage, resulting in a substantial heat storage capacity. Thermal behavior tests conducted in a wind tunnel revealed that the impregnated bamboo samples effectively mitigate temperature fluctuations by aligning them with the PCM’s phase change temperature. Additionally, it was observed that air flow velocity had an impact on this phenomenon. The study concluded that bamboo culms impregnated with PCM hold promise for temperature regulation in construction applications, with variations in airflow exerting an impact on the outcomes obtained.

Boron doping enhancing the sodium storage capacity of lignite-based hard carbon

Boron doping enhancing the sodium storage capacity of lignite-based hard carbon

Simple Synthesis and Sodium Storage Analysis of Ultra‐High Nitrogen‐Doped Core‐Shell Mesoporous Carbon Nanospheres

AbstractThe development of easily synthesized high‐performance anode materials is crucial for the current energy storage (ES) field. Considering the potential of nitrogen‐doped core‐shell mesoporous carbon materials, a simple micelle‐induced high‐temperature pyrolysis method is employed to synthesize ultra‐high nitrogen‐doped (21.1 wt.%) core‐shell mesoporous carbon nanospheres (CYMCS). This material exhibits excellent volume expansion resistance, achieves a high reversible sodium storage capacity of up to 283 mAh g−1 at a current density of 0.1 A g−1, and maintains stable cycling performance for over 10000 cycles at a high current density of 5 A g−1. Moreover, previous research has provided limited insights into the specific mechanisms behind the low initial coulombic efficiency (ICE) observed in CYMCS and other related porous materials. To address this, the study not only delves into the electrochemical performance of CYMCS but also provides a comprehensive analysis of the formation mechanisms of the solid electrolyte interphase (SEI) and the electrolyte decomposition process, revealing the connections between these processes and their impact on ICE. Overall, this research not only offers new insights into the synthesis and performance optimization of CYMCS materials for sodium storage applications but also provides valuable guidance for the design of related carbon materials and strategies to improve ICE.

Biomimetics‐Driven Design of Micron‐Sized SiO Composites for High‐Performance Lithium‐Ion Batteries

AbstractMicron‐sized SiO‐based materials have attracted extensive attention in lithium‐ion batteries due to high theoretical capacity and low‐cost. However, their development is seriously hampered by the large volume change and low conductivity of SiO. Herein, by combining the theoretical prediction with biomimetics‐driven design concept, a unique chloroplast‐like SiO@N‐doped carbon‐carbon coated SnO2 (denoted as SiO‐NC@SnO2‐C) integrative composite is presented through a facile one‐pot hydrothermal route. The resultant SiO‐NC@SnO2‐C anode for lithium‐ion storage shows a high reversible capacity of 1209 mA h g−1 at 0.2 A g−1 after 160 cycles and an outstanding rate capability of 722.7 mA h g−1 at 5 A g−1. In situ TEM technique and cross‐sectional SEM images reveal that the cavity formed in the composite, the flexible carbon interlayer, and glucose‐derived carbon outer layer together play crucial roles in alleviating the volume expansion and improving the structural stability of the electrode. In situ Raman spectra further verify that the highly reversible structure of SiO‐NC@SnO2‐C is responsible for its superior stability. Importantly, the SiO‐NC@SnO2‐C composite also shows an excellent reversible lithium storage capacity of 92.9 mA h g−1 with a 73% of capacity retention after 100 cycles at 1 C in full‐cells.

Graphene-Based Microelectrodes with Reinforced Interfaces and Tunable Porous Structures for Improved Neural Recordings.

Invasive neural electrodes prepared from materials with a miniaturized geometrical size could improve the longevity of implants by reducing the chronic inflammatory response. Graphene-based microfibers with tunable porous structures have a large electrochemical surface area (ESA)/geometrical surface area (GSA) ratio that has been reported to possess low impedance and high charge injection capacity (CIC), yet control of the porous structure remains to be fully investigated. In this study, we introduce wet-spun graphene-based electrodes with pores tuned by sucrose concentrations in the coagulation bath. The electrochemical properties of thermally reduced rGO were optimized by adjusting the ratio of rGO to sucrose, resulting in significantly lower impedance, higher CIC, and higher charge storage capacity (CSC) in comparison to platinum microwires. Tensile and insertion tests confirmed that optimized electrodes had sufficient strength to ensure a 100% insertion success rate with a low angle shift, thus allowing precise implantation without the need for additional mechanical enhancement. Acute in vivo recordings from the auditory cortex found low impedance benefits from the recorded amplitude of spikes, leading to an increase in the signal-to-noise ratio (SNR). Ex vivo recordings from hippocampal brain slices demonstrate that it is possible to record and stimulate with graphene-based electrodes with good fidelity compared with conventional electrodes.

Theoretical estimations of carbon geological storage capacities in the deep aquifer in Songliao Basin: Insights from spatial stochastic simulation.

Accurately assessing the carbon dioxide (CO2) storage capacity of deep saline aquifers is critical for the implementation of carbon geological storage (CGS) project, especially considering the sparsity and heterogeneity of hydrogeological data. In this study, we developed variogram models for key parameters influencing CO2 dissolution storage capacities, such as porosity, temperature, pressure, and concentration of NaCl, then conducted 100 Sequential Gaussian Simulations (SGSs) for each parameter to derive the spatial distribution of CO2 solubility. This grid-based stochastic simulation approach provides a more accurate representation of spatial heterogeneity than using average values, and we further assessed CO2 storage capacity uncertainty across 100 simulations. The findings indicated that, within a 95% confidence interval, the theoretical storage capacity ranges from 3.38Gt to 9.39Gt. Moreover, the SGS-based approach mitigates the smoothing effect commonly associated with Ordinary Kriging. The assessment of potential sites for CGS based on 20-year storage shows that, compared to the P50 scenario, the P90 scenario increases transportation costs by 27.66% for power plant A and 21.88% for power plant B, while the P10 scenario reduces costs by 12.77% for A and 6.25% for B. Overall, this study provides a reliable theoretical assessment in CO2 storage capacity, offering valuable insights for decision-makers in managing the risks and opportunities of CGS projects.

Main characteristics of French farms adopting cereal–legume intercropping: A quantitative exploration at the national and local levels

CONTEXTCereal–legume intercropping is a diversification practice that offers many advantages, especially in low-input systems. However, its adoption remains low on European farms, as technical and economic barriers hinder its development. In recent years, an increase in the proportion of arable land cultivated with cereal–legume intercrops has been observed in France. Three areas in particular – in Western, Eastern and Southern France – seem to be particularly dynamic. OBJECTIVEThis study aimed (i) to identify the main farm characteristics associated with the presence of cereal–legume intercrops at the national level in France and (ii) to highlight more specific characteristics that could explain the particular dynamics observed in each focus region. METHODSWe analysed data from the 2020 French Agricultural Census for 43,968 farms representative of the French arable crop, livestock, and mixed crop–livestock farming systems. Through a literature review, we identified key factors linked to the presence of cereal–legume intercrops and related them to 42 variables in the census. At the national level, the most important of these variables were identified and interpreted using a balanced random forest and a classification and regression tree (CART). We tested the CART obtained at the national level in the Western, Eastern, and Southern areas and conducted a random forest analysis for each area to identify local particularities. RESULTS AND CONCLUSIONAt the national level, the presence of cereal–legume intercropping was strongly linked to organic farming and the presence of livestock, especially ruminants. These intercrops were prevalent on farms with high feed autonomy for the cattle and sheep. Additionally, they were commonly observed on farms with grain storage, possibly indicating feed autonomy, on-farm transformation, or marketing outside of agricultural cooperatives. The belonging to a farm machinery cooperative was also strongly associated with cereal–legume intercropping, likely because these cooperatives give farmers access to specific machinery and provide opportunities for knowledge exchange regarding their practices. Similar characteristics were identified at the local level; organic farming was pivotal in the Western and Eastern areas, followed by feed autonomy for cattle. In the Southern area, however, on-farm grain storage capacity was dominant, likely due to longstanding efforts to achieve feed autonomy. SIGNIFICANCEThis exhaustive study on French farms identified key farm characteristics strongly linked to cereal–legume intercrops adoption. This insight is critical for promoting this practice, whether through national public policies or local farming support services. The methodology proposed can be easily reproduced to investigate other farming practices at different spatial scales.

Design and analyses of an AB5 - metal hydride based canister for hydrogen compressor application

The reversible hydrogen storage nature of metal hydride (MH) is widely accepted for the development of MH based energy devices like energy storage, hydrogen compressors, etc. For efficient working of such devices, the appropriate thermal management of canister is very important i.e. extraction and supply of heat during hydrogenation and dehydrogenation, respectively. The accumulation of heat reduces the hydrogen storage capacity as well as detoriarates the reaction rates because of increase in MH temperature. Therefore, to optimise the MH heat transfer, in the present work, a helical coil is introduced within the MH Canister (MHC) to circulate the heat transfer fluid in addition to an external cooling jacket. The purpose of using helical coil is to get more surface contact with MH because of the poor thermal conductivity of MH. The performance analyses have been carried out through a 3-D Finite Volume Approach employed with La0.9Ce0.1Ni5. The analyses include the influence of coefficient of heat transfer, pressure, and temperature on the designed canister as well as the compressor performance. Initially, the numerical model is validated with experimental results available in the literature and observed in good match. Later, the performance of MHC is predicted for different operating conditions which results in the estimated storage capacity of hydrogen is about 1.48wt% at 25bar and 298K. In addition, it is observed that at an elevated supply pressure, the reaction rates increased as well as the rise in MHC temperature increased due to exothermic heat. Later, the MHC is tested for the application as hydrogen compressor which results in the compression ratio of 10.8 with a discharge pressure of 270bar at 140°C providing ~20% efficiency.

Multi‐Objective Optimization of a Spherical Thermal Storage Tank Using a Student Psychology‐Based Approach

ABSTRACTEnergy storage technologies often store heat, with water as a preferred medium due to its availability and low cost. However, maintaining water in a liquid state at high temperatures requires large pressure vessels, posing significant design challenges. Balancing thermal storage capacity with pressure constraints is essential. This paper explores the dynamics of thermal storage water tanks, aiming to optimize their design using a multi‐criteria approach. An equilibrium thermodynamic model was developed to evaluate the impact of geometric structure and operating parameters. The results show that optimizing a single variable is insufficient to minimize pressure swing, reduce heat loss, and maximize storage capacity. To address these trade‐offs, a multi‐objective student psychology‐based optimization (SPBO) algorithm was employed for three‐objective optimization, outperforming particle swarm optimization (PSO) in convergence. The technique for order preference by similarity to ideal solution (TOPSIS) method was applied to the Pareto frontier, yielding ideal solutions using both data‐driven and manually weighted approaches. Compared with the initial design, the data‐driven weighted (entropy‐weighted and coefficient of variation methods) optimal designs improved all objectives, reducing pressure swing by 12.8% and 19.8%, respectively. A manually weighted approach reduced pressure swing by up to 86.7%, albeit with a decrease in thermal storage capacity.

Equivalent system frequency response model with energy storage

Providing Frequency Response (FR) using energy storage system (ESS) has been adopted in power systems worldwide to reduce the maximum frequency deviation. This paper presents a new equivalent system frequency response model with ESS. The model can be conveniently used to assess the system frequency nadir and calculate the capacity and equivalent droop of storage considering the maximum frequency deviation in a synchronous generator (SG) dominated system. Unlike existing calculation methods based on control strategies such as fuzzy-logic, robust control, data-driving control and predictive algorithm, the proposed method (i) uses the equivalent capacity and equivalent droop to describe the FR of SG and ESS, thereby avoids the difficulty in solving high-order FR model and (ii) does not need the control strategy of SGs in the network. Therefore, the proposed method provides a simple yet systematic method in calculating the capacity and equivalent droop of ESS. The effectiveness of the proposed method is demonstrated using the four-generator two-area (4G2A) system with 0 %, 25 % and 50 % penetration of renewable resources and different types of SGs (hydraulic and steam SG) based on the given maximum frequency deviation..

Hydrogen bond chemically mediated closed pore in hard carbon extending low-voltage plateau capacity for sodium storage

Hydrogen bond chemically mediated closed pore in hard carbon extending low-voltage plateau capacity for sodium storage

Effect of shrubland-to-grassland conversion on soil water storage and infiltration capacity in Loess Plateau region of China

Effect of shrubland-to-grassland conversion on soil water storage and infiltration capacity in Loess Plateau region of China