Energy Storage最新文献

In this research, the synthesis of a binary composite was conducted by combining Cu-MOF and Bi₂WO₆. The resulting composite, denoted as CuBW, was systematically prepared with varying weight percentages: CuBW20, CuBW50, and CuBW80. To assess the properties of the composites, multiple characterization techniques were employed, including FTIR, XRD, FESEM-Elemental Mapping, BET-BJH, TEM, HRTEM-SAED, and XPS. The composites were subjected to electrochemical testing utilizing a three-electrode system, with 3 M KOH serving as the electrolyte. Through the electrochemical study, various parameters were evaluated and subsequently compared to determine any differences or similarities among the different compositions. CuBW80 exhibits superior performance with a specific capacity of 1137 F g⁻¹, specific energy of 11 Wh kg⁻¹, and specific power of 4000 W kg⁻¹ at an operating current density of 0.5 A g⁻¹. In the cyclic stability test, CuBW80 demonstrated superior performance by retaining approximately 83% of its initial specific capacitance over 10000 cycles. This further highlights its resilience and durability, reinforcing its suitability for extended and reliable use in energy storage applications.

We investigate the influence of phosphoric acid (H₃PO₄) activation on physiochemical characteristics of activated carbons (ACs) as a function of number of activation steps such as two-step and three-step and impregnation ratio (IR). Scanning electron microscopy observations identified that different morphologies in the forms of graphene sheet-like, nano-granular, and flake-like carbon structure in the cases of ACs. FTIR spectroscopy confirmed that successful incorporation of phosphorous group in the ACs by H₃PO₄ activation. X-ray diffraction (XRD) profile exposed that irrespective of the activation method and IR, all AC samples showed narrow and sharp XRD crystalline peak along with the amorphous signals. Raman scattering analysis suggested that three-step activation create more defective structure as compared to two-step activation route. Nitrogen adsorption–desorption isotherm measurements indicated that upon fabricating ACs via three-step and two-step activation approach, around 6.5 times and 3-fold enhancement in the value of surface area of ACs as compared to that of carbon before activation. In addition, higher the IR value, lower the textural properties of ACs. This study demonstrated that three-step activation methodology is capable of generating highly porous AC when compared to two-step activation route. Cyclic voltammetry analysis showed that for the electrode developed from AC that fabricated via three-step activation, capacitance retention of 50% is achieved upon tuning the scan rate by 10 times. The same electrode exhibited the capacitance retention of 45% upon increasing the current density by 10 times. We have also compared the electrochemical performance of symmetric and asymmetric supercapacitors. Electrochemical capacitance retention of symmetric and asymmetric supercapacitors is determined to be 100% and 92% respectively after 1000 cycles at the current density of 1 A g⁻¹. Based on the Ragone plot study, it is observed that the maximum energy density of 5 W h kg⁻¹ and the maximum power density of 943 W kg⁻¹ are attained for the case of symmetric supercapacitors. Asymmetric supercapacitor displayed improved energy density of 7.15 W h kg⁻¹ and modest power density of 432 W kg⁻¹.

The development of the battery-type electrode for the hybrid supercapacitor is very challenging owing to poor cycle stability. To overcome this problem, heterostructures would be an excellent alternative attributed to the synergetic effect of different materials physical properties, including electrical conductivity, mechanical flexibility, and so forth. Furthermore, heterostructures also offer significant redox reactions on account of more active sites, enhanced charge transfers kinetics via extra electron carriers, and ion diffusion rates, along with improved cyclic stability. Herein, we prepared heterostructures of Co₃O₄ nanospheres and WO_3−x nanorods via a single-step wet chemical method at a reaction time of 1 h (CoW1) and 6 h (CoW2). The electrochemical investigations reveal improved specific capacitance of CoW1 (157 F g⁻¹) than CoW2 (188 F g⁻¹) at 0.3 A g⁻¹. Furthermore, an aqueous hybrid supercapacitor (AHS) shows the specific capacitance of 38 F g⁻¹ at 1 A g⁻¹. Notably, it exhibits a remarkable specific capacity retention of 93% up to 10 000 cycles at 100 mV s⁻¹. Thus, CoW2 have great potential of electrode materials for the next-generation energy storage devices.

Metal-ion batteries are in huge demand to cope with the increasing need for renewable energy, especially in automobiles. In this work, we apply first-principle calculations to examine two-dimensional beryllium carbide (2D-Be₂C) as a possible anode material for metal-ion (Na and K) batteries. 2D-Be₂C is a semiconductor and becomes metallic by adsorbing metal ions. Negative adsorption energy indicates stable adsorption on the monolayer of Be₂C. Alkali metal diffusion barrier and optimum path for minimum energy are studied within the framework of the climbing image nudged elastic band method. Here, six intermediate images are considered between the initial and final states. The lowest diffusion barriers for a single adsorbed Na and K atom are 0.016 and 0.026 eV, respectively. A maximum open circuit voltage of around 1 V is computed for K ions, whereas 0.5 V is for Na ions. Also, the maximum storage capacity of the Be₂C monolayer is estimated at 1785 Ah/kg.

Lithium-ion batteries are vital power sources for modern society, especially mainly powered electronic devices, electric vehicles (EVs), and future stationary energy storage. Battery cost is still challenging for EVs and large-scale applications that continuously require the development of low-cost and abundant elements-based materials for sustainable battery manufacturing. SiO₂ derived from rice husks emerges as a promising anode material owing to its advantageous raw source and cost-effectiveness. However, the material's low electronic conductivity and poor lithium-ion diffusion rate make it unsuitable for fast-charging or high-power applications. To overcome these challenges, graphene nanoplatelets have been introduced as a conducting additive to enhance electronic conductivity and optimize lithium diffusion in the battery. In this research, an ultrasonic method was utilized to create a composite of C/SiO₂/graphene using C/SiO₂ derived from rice husk and graphene nanoplatelets. The mixture containing 85 wt% of graphene exhibited superior electrochemical performance among the investigated ratios with excellent cycling performance (305 mAh g⁻¹ with capacity retention of 86.18% after 50 cycles at 0.1 A g⁻¹) and an impressive rate capability (69.9 mAh g⁻¹ at a high current of 2.0 A g⁻¹, nearly three times higher than the bare C/SiO₂). XPS and GITT analysis confirmed that the solid electrolyte interphase (SEI) layer on the C/SiO₂/graphene electrode was more stable and conductive due to higher LiF-Li₂CO₃ content, which enhanced the lithium diffusion from the graphene's high surface area.

With advances in technology and the increasing use of nanomaterials, ongoing research is focused on improving the performance of thermal systems. This study investigates the thermal conductance (UA) of a radiator using aqueous suspensions of carbon nanotubes (CNTs), which are among the nanomaterials with the highest heat transfer coefficient. For this purpose, three different nanofluids were prepared, each with varying concentrations of single-walled carbon nanotubes (SWCNTs) and multi-walled carbon nanotubes (MWCNTs). The heat transfer performance of three hybrid nanocoolant fluids (NF), namely, NF1 (0.8 wt% MWCNT + 0.4 wt% SWCNT), NF2 (0.4 wt% MWCNT + 0.4 wt% SWCNT), and NF3 (0.4 wt% MWCNT + 0.8 wt% SWCNT), was experimentally examined and compared with water. The results show that CNT suspensions can enhance heat transfer by up to 16.9% compared with the base fluid, and SWCNTs were observed to have better thermophysical qualities than MWCNTs.

This study investigates the potential of using phase change material (PCM) in a building using an air handling unit (AHU) assisted by solar energy. To further enhance the system, an energy storage system (ESS) can be considered. Implementing ESS would allow the captured solar energy to be stored efficiently, ensuring a continuous and reliable power source for cooling or heating the air, even during non-sunlight hours. The air-conditioned zone is considered to be 220 m² in which 30 people work for 12 h a day. An energy analysis is conducted to evaluate the performance of the proposed system in terms of energy and exergy loss. The genetic algorithm (GA) method is used to optimize the system. The results indicate that the system, including PCM and solar system, can reduce energy consumption by up to 8.9% compared to conventional AHUs in the hottest month of the year (July). The results indicated that employing PCM leads to a decrease of 124 kWh in heat loss during January and 229 kWh in heat gain during July. Taking into account the beneficial impacts of both PCM and the solar system, the yearly assessment demonstrates a 2.69% reduction in power demand, equating to an energy saving of 679 kWh. Furthermore, PCM in the proposed system can be used in integration with AHUs based on renewable energy systems to store renewable energy for buildings.