Energy Storage最新文献

Activated carbon derived from cocoa pod husk was engineered for solid-state energy storage applications through controlled KOH activation. The effects of KOH concentration and immersion duration were systematically evaluated to optimize pore development and electrochemical behavior. Carbonization at 500°C followed by activation at 700°C significantly enhanced textural characteristics, leading to a maximum surface area of 431.73 m² g⁻¹ and average pore radius of 1.759 nm at 12 h immersion. Electrochemical measurements using a PVA–K₂CO₃ gel electrolyte demonstrated improved charge storage performance, particularly for carbon activated with 5 M KOH for 12 h. The results confirm that optimized alkaline activation creates a hierarchically porous and conductive carbon network capable of efficient ion transport and charge accumulation. This work highlights cocoa pod husk as a promising and sustainable precursor for high-performance solid-state energy storage electrodes.

Thermal energy storage (TES) systems play a vital role in enhancing energy efficiency and reducing dependence on nonrenewable resources. This study investigates the synergistic integration of triangular fins and nanoparticle-infused phase change materials (PCMs) to enhance heat transfer in a large triplex tube heat exchanger (TTHX). Numerical simulations, conducted using ANSYS Fluent 15 software, supported by experimental validation with an average deviation of around 2%, were used to evaluate fin placement, fin geometry, and the effect of 10 wt% Al₂O₃ nanoparticles into the PCM. Results show that triangular fins significantly improve heat transfer, with external fins providing the fastest melting. The addition of nanoparticles increases thermal conductivity by nearly 25% and, when combined with optimized fins, reduces the melting time to 163 min. Energy-performance analysis confirms that nano-PCM accelerates charging due to enhanced conductivity, while pure PCM retains higher total stored energy. The optimal configuration, where eight external copper fins of 141 mm length and an 18% aspect ratio, delivered the best overall performance. These findings demonstrate that combining fin-geometry optimization with nanoparticle enhancement substantially improves TES efficiency. The proposed approach is well-suited for solar thermal systems, industrial waste-heat recovery, and compact TES applications.

The intelligent design of highly electrochemically active materials to achieve superior energy and power densities is always critical for energy storage systems. Herein, a novel strategy is developed to design unique metal chalcogenides (Bi–Zn–Se). A hierarchical design of chalcogenide adorned with coral reef-like copper structures via electrodeposition is directly used as the positive supercapacitor electrode. Moreover, biomass-derived hollow carbon structures synthesized via pyrolyzation are employed as a negative electrode in the hybrid device. The hierarchical architecture of both positive and negative electrodes, coupled with strong electroactivity and simple electrolyte permeation, results in significantly increased electrochemical performance, with specific capacitances of 230 F g⁻¹ at a current density of 1 A g⁻¹. The assembled Cu@Bi–Zn–Se//C battery-type device delivers superior energy density of 85.2 Wh kg⁻¹ and outstanding power density of 817.92 W kg⁻¹. Overall, creating heterostructures by combining electro-active materials was a fruitful approach to producing a high-performance battery-type hybrid energy storage device.

In this research, a homobinuclear complex (di-μ-chlorobis[2-[(dimethylamino)methyl]phenyl-C,N]dipalladium(II)) was used as a synthon to prepare a palladium/palladium oxide quantum dot composite. A novel method was employed to prepare the metal/metal oxide composite using an autoclave system in a microwave device with perchloric acid as an oxidizing agent. The nanocomposite was characterized using X-ray diffraction to determine the type of the composite and then it was characterized by TEM to determine the size and shape of the particles. The results confirmed the presence of palladium and palladium oxide peaks in XRD. Furthermore, the TEM measurement confirmed the presence of the material in the form of quantum dots with a size not exceeding 8 nm. The electrical properties of this composite were examined to confirm its suitability for use in supercapacitors. The results show that the real dielectric constant of Pd/PdO decreases as the frequency increases, indicating a weaker response at higher frequencies. The imaginary dielectric constant is relatively stable across different frequencies. The electrical conductivity gradually increases with frequency, especially at high frequencies. The real dielectric constant of Pd/PdO starts from 0.327 at Log Hz = 2.01101 and continues to decrease to 0.01219 at Log Hz = 5.01101. The imaginary dielectric constant ranges from 0.02644 to 0.02111 across frequencies from Log Hz = 2.01101 to Log Hz = 5.01101. The conductivity starts from 2.214E⁻¹ at Log Hz = 2.01101 and reaches 2.629E⁻¹ at Log Hz = 5.01101 with a noticeable increase at high frequencies. The prepared quantum dots were used as electrodes for supercapacitor application and the results demonstrate that the supercapacitor charged to 2.65 V using sodium sulfate as an electrolyte.

Various heat transfer augmentation techniques have been investigated to address the low thermal conductivity nature of phase change materials (PCMs). However, the techniques may also accelerate the heat exchange between the system and its surroundings, which increases the heat leak into the system during the cold holding process, particularly in prolonged cold thermal energy storage (CTES) systems. Hence, comprehensive evaluation is crucial for researchers to develop enhancement techniques that enable faster charging and slower discharging rates. This review comprehensively evaluates different passive heat transfer enhancement techniques, including fin addition, storage container optimization, nanomaterial dispersion, metal foam embedding, and hybrid methods. It identifies enhancement methods and their key parameters and factors favorable for prolonged CTES systems, based on their distinct impacts on the melting and solidification rates. The review reveals that incorporating nanomaterials at higher concentrations, metal foams with lower porosities, and convective flow restricting fins demonstrate higher solidification and slower melting rates, resulting in faster charging and prolonged cold retention durations. In contrast, adding fins that facilitate natural convection and embedding metal foams with higher porosities exhibit comparable melting and solidification rates. Additionally, the review includes performance limitations and life-cycle aspects of enhanced PCMs. Moreover, various techniques, including spatiotemporal PCMs, form-stable cold thermal energy storage phase change materials (FCPCMs), and double-layer insulations, significantly improve the cold retention duration of PCMs used in long-term CTES systems. It also highlights the challenges and future prospects, focusing on developing phase change CTES systems for prolonged cold storage, emphasizing performance, cost-effectiveness, scalability, and sustainability.

To mitigate the volatility associated with renewable energy generation, energy storage technologies are essential for shifting energy across time and space by capturing surplus electricity and discharging it during deficits. This capability is vital for enhancing energy efficiency and facilitating the extensive integration of renewables. This study develops and evaluates two Advanced Adiabatic Compressed Air Energy Storage (AA-CAES) configurations: a three-stage compression/expansion system and a four-stage counterpart, both designed for an 8-h charge and 4-h discharge cycle. Thermodynamic and economic models were constructed to assess their performance. The simulation indicates that the three-stage system achieves a round-trip efficiency (RTE) of 76.20% and an energy generation per unit volume (EGV) of 6.67 kWh/m³, leaving 207.88 tons of residual hot water. In comparison, the four-stage system shows a slight decline in RTE by 1.23% and EGV by 0.41 kWh/m³, but generates a significantly higher surplus of hot water (increased by 171.82 tons). Economically, the levelized cost of energy (LCOE) is 0.1067 $/kWh for the three-stage system and 0.1104 $/kWh for the four-stage system, with dynamic payback periods (DPT) of 1.6 and 1.7 years, respectively. To address the substantial hot water surplus in the four-stage design, an Organic Rankine Cycle (ORC) was integrated for waste heat recovery. This integration improved the system's work capacity, RTE, and EGV. Although the initial capital expenditure rose due to additional equipment, the slight dip in economic metrics is negligible compared to the thermodynamic gains.

This study examines the thermal behavior of Li-ion batteries (LIB) under high discharge rates, emphasizing the necessity of an efficient battery thermal management system (BTMS) employing phase change materials (PCMs). Without any thermal regulation, the battery temperatures rose sharply to 66.16°C, 74.8°C, and 82.40°C at 3C, 4C, and 5C discharge rates, respectively—well above the safe operating threshold. Incorporating a PCM-based BTMS significantly mitigated this rise, lowering the maximum temperatures to 29.69°C, 30.74°C, and 31.78°C, corresponding to reductions of approximately 55.12%, 58.91%, and 61.43%. Among the four PCMs tested (RT-28, RT-31, RT-33, and RT-35), RT-28 demonstrated superior thermal performance, exhibiting the lowest temperature rise and the highest energy absorption (1.9 kJ at 5C), compared to RT-31 (1.7 kJ). At 5C, RT-28 achieved a liquid fraction of 51.17%, while RT-31 reached a liquid fraction of 44.48%. Over time, thermal resistance increased for RT-28, RT-31, and RT-33, with RT-31 peaking at 3.95 mΩ, whereas RT-35 remained nearly constant at 3.80 mΩ. These results highlight that selecting PCMs with phase change temperatures closely matching the battery's operational range can effectively enhance safety, suppress thermal runaway, and improve performance in high-power applications such as electric vehicles (EVs) and renewable energy systems.