The impact of the mushy zone parameter ( A mushy ) and thermal properties during the solidification of a commercial paraffin-type PCM in a vertical cylinder under T-history conditions was examined numerically. First, the thermal properties of the paraffin-type PCM and its temperature profile during solidification under T-history conditions were experimentally obtained. The solidification process is simulated by using a numerical model and it was conducted via the commercial CFD code ANSYS FLUENT 2022. R2. The enthalpy‒porosity model was employed by the ANSYS FLUENT for solidification and melting. The accuracy of a simulation is highly sensitive to the software inputs and assumptions. Therefore, selecting the correct values for thermal properties and the mushy constant is essential for achieving precise simulation results. To determine the precise boundary conditions, radiative heat transfer between surfaces is considered. The results indicate that, between the four thermal properties, although increasing the thermal conductivity accelerates the solidification rate, the opposite effect is observed with increasing latent heat, density, and specific heat, as higher values of these properties lead to slower cooling. Moreover, the results highlight that choosing the correct mushy zone parameter is crucial for accurate solidification modeling. Although the impact of   A mush on solidification is generally less pronounced because conductive heat transfer dominates compared with the melting process, for paraffin-type PCMs, a higher   A mush value yields results that better align with experimental data, unlike other PCM materials. Furthermore, the shape and progression of the solidification is influenced by the mushy zone parameter and as A mushy increases, solidification in the bottom layers decreases, with the process becoming more concentrated in the layers closer to the cold wall.

To fulfill the increasing energy demands of the world through renewable energy sources requires the utilization of a highly efficient large-scale electrochemical energy storage device. A hybrid Supercapacitor (HSC) that consists of a battery-type electrode coupled with the counter capacitive electrode, while in principle offering supercapacitor-like power and cyclability values and higher energy density can be a potential device as a large-scale energy storage device to cater to the energy needs through renewable energy sources. The KCo 0.5Ni 0.5PO 4 electrode demonstrated a notably enhanced electrochemical performance attributed to the synergistic interaction of Co 2+ and Ni 2+ ions in a phosphate framework. The incorporation of redox-mediated diffusive charge storage through the incorporation of Ni 2+ on the Co 2+ site resulted in a large-scale charge storage capacity coupled with capacitive-type surface charge storage on the KCo 1-xNi xPO 4 electrodes. The KCo 0.5Ni 0.5PO 4 delivers 173 mAh/g (capacitances: 1038 F/g) at a current density of 0.5A/g in an aqueous 2M KOH electrolyte accompanied by cyclic stability up to 5000 cycles. HSC mode consists of Activated Carbon as the negative electrode along with KNi 0.5Co 0.5PO 4 as the positive electrode displaying high energy density and power density of 183.7 Wh/kg and 7952W/kg respectively, in 2M aqueous KOH electrolyte. The superior full performance in HSC mode makes KCo 0.5Ni 0.5PO 4 a potential positive electrode for the development of high-performing HSCs.

In the rapidly evolving landscape of energy storage technologies, sodium-ion batteries (SIBs) have emerged as promising alternatives to conventional lithium-ion batteries. SIBs exhibit moderate to high specific energy ranging from approximately 70 to 170 Wh/kg, ensuring suitability for diverse applications. Furthermore, with their abundance of raw materials and potential for lower costs, sodium-ion batteries are attracting significant interest from researchers, manufacturers, and investors. This heightened interest is evidenced by the exponential growth in the number of patents filed for SIBs over the past decade, totalling 131,026 patents. This surge in patent filings underscores the growth pattern of SIBs as promising alternatives in the energy storage landscape. In this dynamic environment, securing and maintaining a robust patent portfolio is imperative for companies and innovators to establish a competitive edge, enabling them to capitalize on the increasing market demand. This article examines the strategies involved in building, protecting, and managing a robust patent portfolio as well as provides intellectual property challenges and patent filing opportunities in SIB technologies.

Two nano-precursors with capping agent were incorporated in stearyl alcohol-adipic acid combination phase change material in this study. The addition of nanomaterials made the eutectic reliable in the manner of its thermal properties like higher enthalpy, degradation point and more compatible with the metal encapsulation materials when compared with the pristane eutectic. The importance of nano-metal oxides in parent material was shown by the reduced time frame of the PCM’s thermal energy storing and releasing process for space heating applications. The specific heat capacity of both the aluminium and titanium oxide nanocomposites were greater than the eutectic which indicates that the material can retain more energy. The thermal conductivities of base material and nanocomposite PCMs were 0.2686, 0.2815 and 0.4395 W/mK at 40 °C and the highest percentage increment of nanocomposites was seen as 9.19 and 63.62 % at varied encircled temperatures. The crystal structure and chemical disintegration was evinced with the X-ray diffractometer results of the composites.

Given the growing demand for new materials for supercapacitor applications, high entropy alloys (HEAs) are being extensively investigated. They are an efficient alternative to existing energy sources due to their synergistic contribution from individual element. We demonstrate the development of nanostructured HEA (FeCoNiCuMn) as a cathode material with specific capacitance (C s) of ~388 F g -1 (5 mV s -1). As anode material, green graphene (rice straw biochar) synthesized using pyrolysis shows a maximum C s of ~560 F g -1 at similar scan rate (5 mV s -1). A hybrid asymmetric liquid state device was assembled using the FeCoNiCuMn nanostructured HEA and green graphene as electrodes. Utilizing the green source, the device provided a high C s of 83.22 F g -1 at 2 A g -1. The specific energy of the device was 33.4 Wh kg -1 and specific power of 1.7 kW kg -1. The electrochemical behavior of each element in the high entropy composition was studied through post X-ray photoelectron spectroscopy and scanning electron microscopic analysis. The chemical behavior of FeCoNiCuMn is further investigated using DFT studies. The enhanced electrochemical properties and synergistic contribution of each element of the HEA is studied via of d-band theory. The current work can be utilized to develop asymmetric hybrid supercapacitors as environmental friendly energy source.

Generation of green energy is critical for addressing the environmental pollution and saving aquatic life in future by reducing the greenhouse gas. Green energy is generated using sources like wind, water, sun, living plants etc. These sources are essential for long-term efforts to mitigate climate change. The large-scale use of green energies will contribute to sustainable development which ensure access to reliable, and chemical free energy to power up the portable devices. This research paper proposes design of Green rechargeable and regenerative battery for brighter future. The proposed battery is not only rechargeable and eco-friendly but also non-flammable and can survive at extreme weather conditions T=70 0 C (V=1.52 V, I=75.5 µA) and T=-65 0 C (V=1.2 V, I=55.2 µA). The electric current of the designed battery also depends on shaking/rotation. The proposed battery can charge 80-90% of its initial value within 30-40 minutes which makes it a favourable candidate where faster recharging is needed. The designed battery does not show any heating effect even at T=70 0 C. Since, battery is free from any chemical, it is therefore does not release any hazardous chemicals once dispose of.

Melting and solidification of a phase change material (PCM) is investigated experimentally by applying a partial filling strategy to the hybrid enhancement of heat pipe-metal foam (HP-MF) in a vertical cylinder. HP-MF enhancement can improve the heat transfer capacity of the PCM system as it combines HP’s efficient heat transfer capacity with MF’s highly effective thermal conductivity capability. The experimental results demonstrate that the partial filling strategy in the melting and solidification of HP-MF PCM can be optimized for effective MF utilization in the HP-MF PCM system. A filling ratio of 83% of MF in HP-MF PCM shows almost identical total melting and solidification along with a temperature distribution to that of an HP-MF PCM (95% porosity, 20 pore density (PPI)). It is plausible to conclude that the removal of 33% or less mass had no significant effect on the overall melting process of HP-MF PCM. It should be noted that the HP-MF PCM system’s heat pipe heat transfer efficiency significantly decreased during the melting process when the MF filling ratio was 37.5% and 12.5%.

The increasing installment of solar and wind renewable energy systems create a volatile energy demand to be met by electricity providers. A nuclear hybrid energy system is a nuclear reactor with energy storage that integrates into the grid with renewable energy sources. The Natrium design by TerraPower and GE Hitachi is a sodium fast reactor with molten salt energy storage. The Natrium design operates at steady state of 345 MW e and can boost up to 500 MW e for 5.5 hours. This study uses Dymola and the Modelica language to model the Natrium-based NHES. The dynamic system model is tested using hourly historical data form Texas (ERCOT) 2021 to show how renewables affect the electricity demand and how energy storage affects the Natrium system response to the demand. According to the results, while the available storage will allow the Natrium design to boost electricity production when the demand and electricity price is high making it more economically viable, the current molten salt storage is undersized for the ERCOT market.

Driven by the goal to achieve sustainable mobility, mitigate climate change, and reduce greenhouse gas emissions, electric vehicles (EVs) represent a radical paradigm shift in the automotive industry. Significant progress has been made in electric vehicle (EV) technology in recent times, including enhancements in battery efficiency, range, and charging infrastructure. As the main energy storage option for electric vehicles, lithium-ion battery technology has advanced significantly, increasing energy density and lowering costs. Wider acceptance of EVs has also been encouraged by the development of fast-charging stations and smart grid integration, which have greatly solved issues with convenience and charging time. However, lithium-ion cells used currently have a working temperature range of 15 o C to 35 o C. The temperature above or below can affect the battery performance and range of the vehicle. Thus, implementation of proper Battery Thermal Management System (BTMS) is required to achieve effective cooling performance and maintain the cells within operating range of temperatures. The current study focuses on the use of fly ash nanoparticles dispersed in base fluid water-ethylene glycol to be used as coolant in indirect liquid cooling system. An ANSYS FLUENT model is developed for 14 LFP cylindrical cells having 2S7P arrangement with serpentine cooling channel in between the cells. The current study uses 5 % particle concentration fly ash nanofluid as coolant to understand the rise in temperature at the outlet for different flow velocities. The better cooling performance was observed for fluid flow rate of 0.1 m/sec with an outlet temperature rise of 311.976 K along with rise of 4 % in temperature compared to inlet fluid flow temperature of 300 K. The percentage difference between the rise in temperature of the outlet for the fluid at 0.1 m/sec and 3 m/sec is 3.07 % indicating effective cooling at lower fluid flow velocities. Thus, by the use of Fly ash as nanofluid in battery cooling application will certainly help to reduce the temperature of battery pack and can provide to be a sustainable solution leading to lesser degradation of environment.

Vanadium electrolyte is one of the most critical materials for vanadium redox flow batteries (VRB). Reducing the cost of vanadium electrolyte and improving its performance are ongoing research priorities for VRB. Currently, the control of the cost of vanadium electrolyte mainly relies on the development of new processes and optimization of traditional processes. Improving the performance of electrolytes mainly involves two aspects: mass transfer and charge transfer, such as introducing additives, optimizing supporting electrolytes, and developing new electrode catalysts. This article reviews the progress in improving the performance of VRB in the past 10 years, including three main aspects: the preparation of electrolytes, the influence of mass transfer on battery performance, and the influence of charge transfer on battery performance. Further discussed the impact of different factors on the improvement of VRB performance. Finally, summarized the challenges faced by VRB in performance improvement and commercial applications, and made suggestions for future research and development of VRB.

Defect engineering and metal decoration onto 2-D materials have gained major attention as a means of creating viable hydrogen storage materials. This Density Functional Theory (DFT) based study presents lithium decorated single vacancy (SV) and Stone-Wales (SW) defective silicene as a viable media for storing hydrogen via physisorption. Introducing defects increases the Li adatom’s binding energy from -2.36 eV in pristine silicene to -3.44 eV and -2.73 eV in SV and SW silicene, respectively, thus preventing Li adatom clustering. The presence of defects and Li adatom further aid hydrogen adsorption onto the substrates with binding energies present in the US-DOE set range of -0.2 to -0.7 eV/H 2 with the highest binding energy measured to be -0.389 eV/H 2. It was seen that both the Li-decorated defective systems were able to effectively store multiple H 2 molecules up to 28 H 2 with the highest gravimetric density being 5.97 wt %. The projected density of state plots indicates a combined overlap of the Li (p) and Li (s) orbitals with the H (s) orbital leading to enhanced H 2 binding energies. Molecular dynamic simulations conducted at 300 K confirm the stability of the Li adatom as well as the adsorbed H 2 molecules at room temperature, establishing the viability of these systems as effective, high gravimetric density, physisorption-based hydrogen storage media.

Phase change heat storage can solve some new energy intermittent and waste heat recovery problems, but heat storage is needed to act as this energy hub. Since the direct contact heat accumulator has the advantages of simple structure, large heat transfer area, and small heat transfer resistance, it is a good choice for improving energy storage rate. Although a great deal of research has been done on phase change materials and heat accumulators over the years, a systematic review of direct-contact heat accumulators is lacking. This paper reviews the related research on direct contact heat storage, aiming to summarize the research work on direct contact phase change heat storage systems. Various phase change materials (PCMs) for direct contact systems are analyzed, and the study of PCM melting crystallization behavior, heat transfer coefficients and system performance in direct contact systems is summarized, as well as the improvement methods for direct contact vessels and PCMs. It provides a useful reference for future research on direct-contact heat storage systems.

This study aims to investigate the effect of NaOH immersion time and concentration on the activation of carbon from Oil Palm Frond (OPF), specifically focusing on the surface morphology and characteristics as the electrodes to biobattery application. The method employed involves carbonization and activation with NaOH at various concentrations: 0.5 M, 1 M, 1.5 M, 2 M, and 2.5 M, along with different immersion times of 12, 18, 24, 30, and 36 hours. Subsequently, the activated carbon is analyzed using a Scanning Electron Microscope (SEM) to observe its morphology, and the Brunauer Emmett Teller (BET) method is utilized to determine the carbon surface area. Furthermore, a voltage test uses a multimeter to assess the electric potential properties. Another outcome of this study is developing a prototype bio-battery POWER. Activated carbon from oil palm frond (OPF) testing resulted in 1 M NaOH, giving the highest surface area of 336.493 m 2g -1, and immersion time at 30 hours gave the optimum result of 396,808 m 2g -1. At the same time, the biobattery electrical test voltage of 0,653 V at a concentration of 1 M and 0,902 V at 30 hours of immersion.

A nickel hydroxide (Ni(OH) 2)-modified reduced graphene oxide (rGO) foam electrode for supercapacitor application is presented in this study. The electrode was made without binder through a one step process. In order to compare the supercapacitor performance of as synthesized graphene foam electrode, rGO and rGO:carbon black (CB) standard electrodes with PVDF-HFP binder were also synthesized . All electrodes were then characterized structurally (XPS, EDS, RAMAN, XRD, and FT-IR) and morphologically (SEM). Ni-containing electrodes were found in the α-Ni(OH)2:rGO structure. NirGO3 has 800 Fg -1 capacitance, while rGO:CB has 900. Thus NirGO3 has the best capacitive performance among binder-free electrodes, comparable to rGO:CB.

This study aims to green synthesize and full characterize CdO nanoparticles by means of an environmentally friendly synthesis using Crocus sativus in its reaction with cadmium ions. The CdO nanoparticles were characterized and their purity was confirmed by XRD and UV.-Vis. spectroscopy. Moreover, scanning electron microscopy (SEM) showed that the prepared cadmium oxide nanoparticles were polymorphic. Furthermore, cadmium oxide nanoparticles were cast in the gas storage (H 2) study. The hydrogen storage results prove that the maximum H 2 uptake was equal to 2.85 Wt.%H 2 at a pressure of 69 bar at 77 K with ∆H=0.62607 KJ/mol H 2 and ∆S=3.35697 J/mol H 2. K. Moreover, the thermodynamic studies under four different temperatures proves that the maximum H 2 uptake could be recorded at a pressure limit of 69-86.2 bar.

The electrochemical and charge storage performance of a fluorine-free structurally flexible pyrrolidinium-based ionic liquid hybrid electrolyte (HILE) in a symmetric graphite-based supercapacitor is thoroughly investigated. The HILE revealed thermal decomposition at 270 ºC, a glass transition (T g) temperature of −73 ºC, and ionic conductivity of 0.16 mS cm −1 at 30 ºC. A systematic variable temperature 1H and 31P NMR spectroscopy and diffusometry, cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), and galvanostatic charge-discharge (GCD) are employed. HILE-based supercapacitor demonstrated a notable specific capacitance of 186 Fg −1 at a scan rate of 1 mVs −1 and a specific capacitance of 122 Fg −1 at a current density of 0.5 Ag −1. The maximum energy density of 49 Wh kg −1, a power density of 370 W kg −1 at a current density of 0.5 A g −1 and a potential window of 4V were obtained. HILE displayed a promising electrochemical performance over a wide potential window of 4V and temperature range (−20 ºC to 90 ºC) in a symmetric graphite supercapacitor.

The electrochemical performance of Polyaniline (PANI) can be significantly improved due to the incorporation of spinel-type transition metal oxide, i.e., 1 wt. % of Nickel Ferrite (NiFe 2O 4) into the PANI matrix. In this report, we have synthesised NiFe 2O 4 (NF), PANI1:1 ratio, PANI1:2 ratio, and PANI/NiFe 2O 4 nanocomposites, i.e., PANI1:1/NF1 and PANI1:2/NF2 nanocomposites by in-situ oxidative polymerization method. The conducting network formed in the nanocomposite significantly increases the multiple valence states of the metal for the electrolytic ions. The PANI/NiFe 2O 4 nanocomposite shows good interaction and was confirmed by Fourier Transform Infra-red Spectroscopy (FTIR) and Raman analysis. The SEM analysis reveals a uniformly porous and agglomerated globular morphology of the nanocomposite. Also, the PANI/NiFe 2O 4 composite (PANI1:1/NF1) exhibits enhanced supercapacitive properties due to improve strong conducting path of PANI, which helps to provide the delocalization of the electrons in the polymeric chain. The highest specific capacitance ~ 758 Fg -1 is achieved for PANI 1:1/NF1 sample as compared to bare PANI1:1 (677 Fg -1), PANI1:2 (500 Fg -1), NF (253 Fg -1) and other PANI1:2/NF2 (686 Fg -1) samples at 10 mV/s scan rate in a two-electrode system due to NF nanoparticles filling the vacant places in the polymeric matrix. The energy density (54 Whkg -1), power density (1705 Wkg -1) and good cycling stability approx. 97 % after 10000 GCD cycles of the device is found for PANI1:1/NF1. The EIS studies further confirm that the PANI 1:1/NF1 device has a lower charge transfer resistance (R ct) ~ 0.35 Ohm in comparison to other fabricated devices. It seems that NiFe 2O 4 acts as a “superhighway” for charge transportation between PANI which is beneficial for supercapacitors.

Microfibrillated cellulose (MFC) with reinforcing effects is a useful building block in the fabrication of flexible and thin supercapacitors. Herein, a hybrid tin oxide-cellulose nanocomposite was hydrothermally produced and coated on MFC thin films to form a supercapacitor. The hybrid tin oxide-cellulose thin films were structurally analyzed using scanning electrode microscopy, Fourier transform infrared spectroscopy and X-ray diffraction. The cellulose thin film with the highest loading of hybrid tin oxide-cellulose nanocomposite exhibited a specific capacitance of 225.88 F/g at 100 mV/s and 486.38 F/g at 20 mV/s in the three-electrode electrochemical system. In addition, it revealed good cyclic stability up to 40 cycles run continuously with 95% cyclic retention. The high specific capacitance and superior cyclic stability could be related to the enhanced charge mobility and ion diffusion between the solid and electrolyte interface. The cellulose thin film coated with flower-like hybrid nanocomposite showed great potential in energy storage.