Energy Storage最新文献

SEM and EDS techniques are carried out to demonstrate the variation of morphology and chemical compound on the surface of graphite anode, which suggest a well-accepted concept that the manganese ions have serious influence on the reversible capacity fade of graphite anode in lithium ion batteries. Based the main chemical compounds of the inorganic layer on the graphite surface, the evolution steps of graphite structure damaged by Mn ions are derived. Although the amount of deposited manganese ions is small, these play an important role in the catalytic decomposition of the electrolyte. Moreover, Raman analysis shows that the structure of the graphite anode becomes irregular at initial SEI formation cycles and tends to be stable at subsequent cycles. This structure variation is probably generated from the manganese ion deposition and the solid electrolyte interphase (SEI) film formation. According to the capacity tests, the cycling performance of NCM811/graphite lithium-ion batteries could be improved 50% by FEC additive and B₂O₃ surface coating. FEC additive maybe benefit graphite forming a stable SEI film in the early stages of cycling to suppress the damage of Mn²⁺ ions, then improving the cycling performance.

Phase change materials (PCMs) are the materials that can absorb and release energy during their phase transition. The materials have become ubiquitous but still face challenges. The inevitable transition from solid phase to liquid phase in these materials during operation limits their utility in application areas that require leak-proof properties like orthopaedic mattresses or gel packs, or applications requiring self-load-bearing capabilities (such as ceiling tiles and building walls). Entrapment of PCM in porous matrices is one of the promising methods of capturing the PCM and limiting the flow of materials in the liquid phase. The present study discusses the preparation of exfoliated graphite from commercially available intercalated graphite. The process of exfoliating the intercalated graphite has been holistically characterized using x-ray diffraction, Fourier transform infrared spectroscopy (FTIR), and scanning electron microscope (SEM). The graphite with a surface area of 47.37 cc/g with a purity of 99% was found to have a maximum absorption of 80% (w/w) stearic acid as PCM. In addition, this paper investigates two synthetic routes to prepare the shape-stabilized PCM. The blends are characterized and compared along six indicators: transition point, latent heat capacity, thermal conductivity, exudation behavior, FTIR, and SEM. Composite 1 refers to stearic acid absorbed in the exfoliated graphite. Composite 2 refers to the stearic acid absorbed in exfoliated graphite which is further treated with an elastomer SEBS. The leak test performed on both blends signifies that SEBS is an essential ingredient. The PCM composition optimized in this study can unlock various thermal applications with critical requirements where direct exposure of chemicals to the user is unacceptable. Further, the study itself is envisaged to serve as a framework to develop enhanced shape-stabilized PCMs with tuneable thermal conductivity and extended operation life in application areas where leakage in liquid phase is a concern.

Due to its high self-heat rate, most researchers have avoided using lithium cobalt oxide (LiCoO₂) in their work, although, major car companies use it to power some car models because of its high-power density. A thermal management system benefits from phase change material (PCM) and serves as a reliable cooling system to ensure the safety, performance, and lifespan of Li-ion batteries. In this study, we conducted an experimental investigation of a new hybrid battery thermal management system (BTMS) using PCM combined with aluminum fins and forced air to enhance the cooling performance of Li-ion battery type 18 650 LiCoO₂. Furthermore, the hybrid model's thermal behaviors are compared with other models that use only air or PCM for cooling. The cooling performance of different BTMS models was tested under a high temperature of 40°C and various discharge rates, as well as, various air velocities. The results demonstrate that the hybrid model effectively minimizes the battery heat accumulation and can reduce the maximum operating temperature by 1.5°C, 5.5°C, and 9.5°C compared to the air-cooling model and by 2.8°C, 5.1°C, and 16.1°C compared to the PCM model for discharge of 1C, 2C, and 3C rates, respectively. Furthermore, the maximum temperature difference within the battery pack did not surpass 3.1°C with our hybrid model. Moreover, the use of our model has a significant advantage in minimizing the air-cooling power consumption by 89%.

This study investigates the use of a saltwater (sodium chloride and water) solution as a phase change material (PCM) in a small fridge for storing scorpion antivenom in Sudan's northern state. The experimental results demonstrate the effectiveness of the PCM in maintaining suitable storage temperature which 3 ± 2°C. By adding salt to the water, the freezing point decreased, enabling the solution to absorb more heat energy because the heat capacity of the saltwater solution is higher than the saltwater ice phase. The base case maintained (2310 g of water only) an average temperature of 9.5°C, while Case 1 (35 g of salt in 2310 g of water) reached 7°C and Case 2 (70 g of salt in 2310 g of water) achieved 5°C. Increasing the amount of saltwater solution led to improved heat absorption. Case 5 (70 g of salt in 4950 g of water) achieved an optimal storage temperature of 4°C. The relationship between outside and inside temperatures showed stable maintenance after initial melting, with a slight increase of approximately 1.5°C. These findings demonstrate the potential of solar-powered fridge with PCM for reliable medication storage in remote areas. By optimizing salt concentration and quantity, temperature-sensitive medications can be stored effectively, improving availability and quality.

Adsorbents heated using solar energy can be used to achieve thermal energy storage and sorption refrigeration with low environmental impacts. This research compares two different methods of heating adsorbents with solar energy to store thermal energy: (1) by exposing the adsorbents to incident light transmitted through a solar collector window, and (2) by heating a highly absorbing solar collector cover, and then transferring the heat from this solar absorber to adsorbents located beneath it. To carry out this comparison experiments are conducted for three cases of adsorbent beds using zeolite 13X and water as the adsorbent-adsorbate pair. In the first case, the top of the adsorbent bed is a polycarbonate sheet, and the zeolites are heated directly by solar-simulated light transmitted through this sheet. In the second case, a blackened aluminum sheet is placed beneath the polycarbonate sheet to generate heat by absorbing incident light. For the third case, the blackened aluminum absorber is placed directly on top of the zeolite beads and the absorber is isolated from the walls of the reactor to avoid heat losses. The outcomes reveal an energy storage density (ESD) of 43.6 kWh/m³ (63.4 Wh/kg) when light is directly incident onto the zeolite 13X and an ESD of 33.3 kWh/m³ (48.4 Wh/kg) when light is incident onto a blackened absorber plate that transfers heat to Zeolite beads residing beneath it. However, ESD values were improved to 48.9 kWh/m³ (71.0 Wh/kg) when the blackened absorber plate was thermally insulated from the walls of the adsorbent bed. These results demonstrate the importance of an optimal absorber arrangement in enhancing the adsorption process for the purpose of elevating energy storage densities.

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 and −2.73 eV in SV and SW silicene, respectively, preventing Li adatom clustering. The presence of defects and Li adatom further aid hydrogen adsorption onto the substrates with binding energies present between the US-DOE set range of −0.2 to −0.7 eV/H₂ with the highest binding energy measured to be −0.389 eV/H₂. The enhanced H₂ binding energies are a result of a combined contribution of the Li(p) and Li(s) orbitals with the H(s) orbital with an indirect electronic transfer from the silicene substrate to the Li adatom. Upon double side Li decoration, both the Li-decorated defective systems were able to effectively store multiple H₂ molecules up to 28 H₂ with the highest gravimetric density being 5.97 wt%. Ab Initio molecular dynamic simulations conducted at 300 K and 310 K confirm the stability of the Li adatom as well as the adsorbed H₂ molecules at room temperature and establish the viability of these systems as effective, high gravimetric density, physisorption-based hydrogen storage media.

Oxide-based solid electrolytes are gaining popularity among researchers owing to their great structural stability. In this work, a novel oxide-based ternary composite (AlPO₄-SiO₂-Li₄P₂O₇) electrolyte is synthesized via a conventional solid-state process with excellent water stability and high ionic conductivity. The crystallographic structure of ternary composite is confirmed using x-ray diffraction and has a significant effect on ionic conductivity. The thermogravimetric analysis result shows a 22.26 wt% loss in the region of 25°C to 900°C due to the evaporation of volatile constituents, including nitrates, carbonates, and moisture. Surface analysis results revealed compact morphology and low porosity with arbitrary grain sizes. Electrochemical impedance spectroscopy has been used to evaluate ionic conductivities. The Mn-ternary composite sintered at 900°C has shown ionic conductivity of 1.63 × 10⁻⁶ S/cm at ambient temperature. 8 wt%-LiBr enhanced the ionic conductivity up to 1.68 × 10⁻⁴ S/cm by significantly reducing the grain boundaries without high-temperature sintering. Results suggested the suitability of LiBr mixed ternary composites as a favorite candidate for lithium batteries in terms of safety, stability, and high ionic conductivity.

Decarbonizing the urban environment has two significant challenges: Increasing electricity demand due to the electrification of space heating and increased renewables share in the electricity supply. The European Commission defines a new grid support mechanism for peak-shaving products in renewed Electricity Market Design. This aims to enable a new market tool to stabilize electric supply and demand. This study examines a grid-integrated thermal storage device's technical feasibility and economic performance to meet net zero building (nZEB) definitions. Alternative scenarios considering current national nZEB targets, present energy market options, and regulations are compared using the life cycle cost and the global warming potentials over the building lifetime. The results show that better building performance is possible even with a low investment increase of 6.7% compared to minimum building standards based on regulations. This enables older building cases to perform similarly with new building targets for Turkish National nZEB. Building electrification using heat pumps and thermal storage systems gives similar economic performances in the long term when a dynamic electricity tariff is available. Adapting the life cycle approach to decision-making in construction contracts can lead to a 50% decrease in building emissions while staying within the same construction budget.

In order to build electrochemical energy storage electrodes, carbon composite materials containing nanosized metal oxides might be desirable. This article describes the designing of TiO₂ aerogel/graphene oxide (TiO₂-A/GO) composites for electrochemical supercapacitors. TiO₂-A was synthesized by a simple sol-gel process followed by annealing at 250°C and thereafter, different concentrations of GO were mixed to prepare TiO₂-A/GO composites via sonochemical method. The intermixing of GO and TiO₂-A in composite was confirmed by observing the structural and crystalline characterizations. Two electrode electrochemical system was used to elucidate the capacitive characteristics of TiO₂-A/GO composite electrode by cyclic voltammetry analysis. In comparison with TiO₂-A electrode, high specific capacitances (C_s) were recorded for TiO₂-A/GO composite electrode. TiO₂-A/2GO composite electrode attained the highest C_s value of ~338.2 Fg⁻¹ at 10 mVs⁻¹ with excellent cycle stability after 2000 cycles. Thus, the prepared TiO₂-A/GO composites-based electrode can be a promising material to achieve good capacitive properties.

Vanadium electrolyte is one of the most critical materials for vanadium redox 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. It focuses on three main aspects: the preparation of electrolytes, the influence of mass transfer on battery performance, and the influence of charge transfer on battery performance. It also further discusses the impact of different factors on the improvement of VRB performance. Finally, it summarizes the challenges faced by VRB in performance improvement and commercial applications, and made suggestions for future research and development of VRB.