Low Energy Research Articles

Picosecond Femtojoule Resistive Switching in Nanoscale VO2 Memristors.

Beyond-Moore computing technologies are expected to provide a sustainable alternative to the von Neumann approach not only due to their down-scaling potential but also via exploiting device-level functional complexity at the lowest possible energy consumption. The dynamics of the Mott transition in correlated electron oxides, such as vanadium dioxide, has been identified as a rich and reliable source of such functional complexity. However, its full potential in high-speed and low-power operation has been largely unexplored. We fabricated nanoscale VO2 devices embedded in a broadband test circuit to study the speed and energy limitations of their resistive switching operation. Our picosecond time-resolution, real-time resistive switching experiments and numerical simulations demonstrate that tunable low-resistance states can be set by the application of 20 ps long, <1.7 V amplitude voltage pulses at 15 ps incubation times and switching energies starting from a few femtojoule. Moreover, we demonstrate that at nanometer-scale device sizes not only the electric field induced insulator-to-metal transition but also the thermal conduction limited metal-to-insulator transition can take place at time scales of 100s of picoseconds. These orders of magnitude breakthroughs can be utilized to design high-speed and low-power dynamical circuits for a plethora of neuromorphic computing applications from pattern recognition to numerical optimization.

Solvent-Activated Transformation of Polymer Configurations for Advancing the Interfacial Reliability of Perovskite Photovoltaics.

Organic materials have been widely used as the charge transport layers in perovskite solar cells due to their structural versatility and solution processability. However, their low surface energy usually causes unsatisfactory thin-film wettability in contact with the perovskite solution, which limits the interfacial performance of the photovoltaic devices. Although solvent post-treatment could occasionally regulate the wetting behavior of organic films, the mechanism of the solid-liquid interaction is still unclear. Here, we present evidence of a possible correlation between the solvent and the wettability of a conventional polymer, poly[bis(4-phenyl) (2,4,6-trimethylphenyl) amine] (PTAA), and reveal the critical roles of Hansen solubility parameters (HSPs) of solvents in wetting mechanisms. Our results suggest that the conventional solvent N,N-dimethylformamide (DMF) improves the wettability of PTAA by the morphological disruption mechanism but negatively impacts interfacial charge collection and stability. In contrast, 2-methoxyethanol (2-Me) with an appropriate HSP value induces the transformation of the PTAA configuration in an orderly manner, which simultaneously improves the wetting property and maintains the film topography. After careful optimization of the surface conformation of the PTAA film, both perovskite crystallization and interfacial compatibility have been enhanced. Benefiting from superior interfacial properties, the perovskite solar cells based on 2-Me deliver a champion efficiency of 24.15% compared to 21.4% for DMF-based ones. More encouragingly, the use of 2-Me minimizes the perovskite buried interfacial defects, enabling the unencapsulated devices to maintain about 95% of their initial efficiencies after light illumination for 1100 h. The present study demonstrates the high effectiveness of solvent-polymer interaction for adjusting interfacial properties and strengthening the robustness of perovskite solar cells.

Achieving Efficient Oxygen Evolution on High-Entropy Sulfide Utilizing Low Electronegativity of Al.

Efficient and stable catalysts are in high demand for accelerating the oxygen evolution reaction (OER). Herein, a high-entropy sulfide (HES) of (FeCoNiCrCuAl)S@HCS with a 3Dstructure is successfully prepared by utilizing a simple one-step solvothermal method and employed as catalyst toward OER. The lower electronegativity of Al compared to the other metal elements and its anti-corrosion character enable an outstanding OER performance of (FeCoNiCrCuAl)S@HCS with an overpotential of 253mV at 10mA cm-2 and an excellent durability after 20000 CV cycles, outperforming the commercial RuO2 and most reported metal-sulfide catalysts. Experiments coupled with theoretical calculations reveal that Al atom primarily serves as electron donor and promotes a redistribution of local electrons from Co and Cr toward adjacent Fe, Ni, and Cu sites. As a result, the Cr-Al site possesses a lowest energy barrier during the rate-determining step and works as the dominant active site for OER process. This study provides a novel insight and strategy into structural design and performance enhancement for HES materials.

Ultrafast Conversion of Water and Oxygen Molecules With Dissociation of Hydrogen Bonding Effect to Achieve Extra-High Energy Efficiency of Secondary Metal-Air Batteries.

Metal-air secondary batteries with ultrahigh specific energies have received vast attention and are considered new promising energy storage. The slow redox reactions between oxygen-water molecules lead to low energy efficiency (55-71%) and limited applications. Herein, it is proposed that the MIL-68(In)-derived porous carbon nanotube supports the CoNiFeP heteroconjugated alloy catalyst with an overboiling point electrolyte to achieve the ultrahigh oxidation rate of water molecules. Structural characterization and density functional theorycalculations reveal that the new catalyst greatly reduces the free energy of the process, and the overboiling point further accelerates the dissociation of O─H and hydrogen bonds, and the release of O2 molecules, achieving an extra-low overpotential of 110mV@10mAcm-2 far lower than commercial Ir/C catalysts of 192mV at 125°C and state-of-the-art. Furthermore, the energy efficiency of assembled rechargeable zinc-air batteries begins to break through at 85°C, jumps at 100°C, and reaches ultrahigh energy efficiency of 88.1% at 125°C with an ultralow decay rate of 0.0068% after 150 cycles far superior to those of reported metal-air batteries. This work provides a new catalyst and electrolyte joint-design strategy and reexamines the battery operating temperature to construct higher energy efficiency for secondary fuel cells.

A comprehensive study on three typical photoacid generators using photoelectron spectroscopy and abinitio calculations.

Conducting a comprehensive molecular-level evaluation of a photoacid generator (PAG) and its subsequent impact on lithography performance can facilitate the rational design of a promising 193nm photoresist tailored to specific requirements. In this study, we integrated spectroscopy and computational techniques to meticulously investigate the pivotal factors of three prototypical PAG anions, p-toluenesulfonate (pTS-), 2-(trifluoromethyl)benzene-1-sulfonate (TFMBS-), and triflate (TF-), in the lithography process. Our findings reveal a significant redshift in the absorption spectra caused by specific PAG anions, attributed to their involvement in electronic transition processes, thereby enhancing the transparency of the standard PAG cation, triphenylsulfonium (TPS+), particularly at ∼193nm. Furthermore, the electronic stability of PAG anions can be enhanced by solvent effects with varying degrees of strength. We observed the lowest vertical detachment energy of 6.6eV of pTS- in PGMEA solution based on the polarizable continuum model, which prevents anion loss at 193nm lithography. In addition, our findings indicate gas-phase proton affinity values of 316.4 kcal/mol for pTS-, 308.1 kcal/mol for TFMBS-, and 303.2 kcal/mol for TF-, which suggest the increasing acidity strength, yet even the weakest acid pTS- is still stronger than strong acid HBr. The photolysis of TPS+-based PAG, TPS+·pTS-, generated an excited state leading to homolysis bond cleavage with the lowest reaction energy of 83 kcal/mol. Overall, the PAG anion pTS- displayed moderate acidity, possessed the lowest photolysis reaction energy, and demonstrated an appropriate redshift. These properties collectively render it a promising candidate for an effective acid producer.

Theoretical Insights into the Mechanism and Origin of Solvent-Dependent Selectivity in the Cyclization of Propargyl Alcohols for the Divergent Synthesis of N-Heterocycles.

This study elucidates the mechanisms and principles governing chemoselectivity in synthesizing two distinct N-heterocycles, benzimidazole thiazine and benzothiazole imidazole, through BF3•OEt2-catalyzed cyclization reactions of propargyl alcohols with benzimidazole thiols. Employing density functional theory calculations, we highlight the crucial role of fluorine source in influencing chemoselectivity. In DCM, BF3, as the catalytic center, coordinates with propargyl alcohol's hydroxyl group to form a precursor. Conversely, in DMF, [BF2•DMF]+, formed from DMF and BF3•OEt2, acts as the catalytic center, activating the propargyl alcohol's hydroxyl group. The mechanisms in both solvents involve sequential steps: B-O bond formation, C-O bond cleavage, S-C bond formation, hydrogen atom transfer (HAT), cyclization, and deprotonation. A notable difference is the HAT process: in DCM, it follows a 1,5-HAT process, while in DMF, BF4- formation from DMF and BF3•OEt2 provides a fluorine source and introduces steric hindrance, favoring a 1,6-HAT process and leading to unique chemoselectivity. This pioneering research showcases the impact of DMF on cyclization reactions, offering valuable insights for comprehending and designing reactions driven by fluorine sources. Crucially, our results propose an innovative reaction mechanism featuring lower potential energy surfaces, enhancing our understanding of the intricate interplay among reactants, catalysts, and solvents.

Workpiece surface laser regulation in laser-induced plasma electrolyte jet machining: Position, shape, and energy

Laser-induced plasma electrolyte jet machining is a new hybrid machining method. This machining method utilizes the plasma impact effect and plasma to increase the inter-pole conductivity for material removal, with low laser energy loss, high material removal rate (MRR), and good surface quality. The advantages of laser machining and electrolyte jet machining are fully utilized. However, it is difficult to avoid refraction of the laser in the electrolyte column, which affects the efficient coupling of the laser to the electrolyte jet machining. In this paper, to improve the localization and MRR, a study is carried out to address the problem of energy utilization efficiency in laser-induced plasma electrolyte jet machining. A compensation model for the refraction of the laser beam in the electrolyte is proposed. Compensation improves the shape and positional accuracy of the laser beam coupled to the electrolyte beam during aluminum alloy machining. Compared before and after compensation, the MRR was improved by 30.2 %, and the groove localization was improved by 37.4 %. Realization of high energy coupling for laser electrolyte jet hybrid machining.

High ionic conductivity materials Li3YBr6 and Li3LaBr6 for solid-state batteries: first-principles calculations

High ionic conductivity solid-state electrolytes are essential for powerful solid-state lithium-ion batteries. With density functional theory andab initiomolecular dynamics simulations, we investigated the crystal structures of Li3YBr6and Li3LaBr6. The lowest energy configurations with uniform distribution of lithium ions were identified. Both materials have wide electrochemical stability windows (ESW): 2.64 V and 2.57 V, respectively. The experimental ESW for Li3YBr6is 2.50 V. Through extrapolating various temperature diffusion results, the conductivity of Li3YBr6was obtained at room temperature, approximately 3.9 mS cm-1, which is comparable to the experimental value 3.3 mS cm-1. Li3LaBr6has a higher conductivity, a 100% increase compared with Li3YBr6. The activation energies of Li3YBr6and Li3LaBr6through the Arrhenius plot are 0.26 eV and 0.24 eV, respectively, which is also close to the experimental value of 0.30 eV for Li3YBr6. This research explored high ionic conductivity halide materials and will contribute to developing solid-state lithium-ion batteries.

The Impact of Low-Power Therapeutic Lasers at 904 nm on the Healing Process of Wounds and the Relationships Between Extracellular Matrix Components and Myofibroblasts.

The goal of the study was to further our understanding of the functions that myofibroblasts do, how they interact with the matrix's extracellular elements, and how laser therapy at 904 nm works. Thirty Wistar rats with superficial wounds on the backs were used in this study. The laser therapy device used two energy levels of a 904 nm laser with an output power of 60 mW. The outcomes had been evaluated for one, three, five, seven, and fourteen days following laser therapy. Numerous methods, including as histology, immunohistochemistry, and scanning electron microscopy, have been used to evaluate the tissues.There was a statistically important (P ≤ .05) decrease in the number of inflammatory cells and the degree of edema after laser therapy. On the other hand, the amounts of elastic fiber as well as collagen slightly increased. On the third post-laser treatment day, there was a statistically significant distinction (P < .05) in the number of myofibroblasts with the desmin; smooth muscle alpha-actin phenotype between the laser-treated and control groups.These results suggest that, compared to a higher energy of 5.6 J, laser therapy at a lower energy of 3.6 J may be more effective in stimulating myofibroblast differentiation during the initial phases of wound healing. These findings show how low-power laser therapy promotes wound healing.

Vibrational relaxation of HOD by collisions with Ar atoms.

Vibrational relaxation of HOD(v12, v3) molecules by collisions with Ar was studied at 298K (v12 denotes coupled bending, v2, and OD stretching, v1, vibrational modes and v3 denotes OH stretching mode). The vibrationally excited HOD molecules were generated by exothermic abstraction reactions of OD radicals with 13 different RH reactants and observed by infrared emission from a fast-flow reactor as a function of Ar pressure and reaction time. State-specific relaxation rate constants were obtained by comparison of the time evolution of the experimental vibrational distributions with numerical kinetic calculations for vibrational populations. The relaxation mechanism was based on the relaxation scheme of H2O studied earlier with the addition of specific channels for HOD(v12, v3). Unlike H2O, energy in stretching and bending vibrations of HOD cannot be separated due to close ν1 and 2ν2 energies, which leads to fast collisional equilibration between these Fermi-resonant levels. For relaxation of the only pure bending state (10), a rate constant of (1.5 ± 0.3) × 10-13cm3molecule-1s-1 was obtained. The relaxation rate of higher v12 states linearly increases with quantum number and very likely includes transfer of population from OD stretch levels, v1, to a lower energy bend level. The average rate constants for the loss of population from (01), (02), and (03) stretching states are (1.1 ± 0.3) × 10-14, (3.2 ± 1.0) × 10-14, and (5.6 ± 1.2) × 10-14cm3molecule-1s-1, respectively.

Encapsulation of Sn Sub-nanoclusters in Multichannel Carbon Matrix for High-Performance Potassium-ion Batteries.

Sub-nanoclusters with ultra-small particle sizes are particularly significant to create advanced energy storage materials. Herein, Sn sub-nanoclusters encapsulated in nitrogen-doped multichannel carbon matrix (denoted as Sn-SCs@MCNF) are designed by a facile and controllable route as flexible anode for high-performance potassium ion batteries (PIBs). The uniformly dispersed Sn sub-nanoclusters in multichannel carbon matrix can be precisely identified, which ensure us to clarify the size influence on the electrochemical performance. The sub-nanoscale effect of Sn-SCs@MCNF restrains electrode pulverization and enhances the K+ diffusion kinetics, leading to the superior cycling stability and rate performance. As freestanding anode in PIBs, Sn-SCs@MCNF manifests superior K+ storage properties, such as exceptional cycling stability (331 mAh g-1 after 150 cycles at 100 mA g-1) and rate capability. Especially, the Sn-SCs@MCNF||KFe[Fe(CN)6] full cell demonstrates impressive reversible capacity of 167 mAh g-1 at 0.4 A g-1 even after 200 cycles. Theoretical calculations clarify that the ultrafine Sn sub-nanoclusters are beneficial for electron transfer and contribute to the lower energy barriers of the intermediates, thereby resulting in promising electrochemical performance. Comprehensive investigation for the intrinsic K+ storage process of Sn-SCs@MCNF is revealed by in situ analysis. This work provides vital guidance to design sub-nanoscale functional materials for high-performance energy-storage devices.

Copper leaching from ultrasonically treated milled waste printed circuit boards: investigation of parameters optimization and kinetics.

Waste printed circuit boards (WPCBs) encompass abundant metals (gold, silver, and copper), along with other harmful materials including brominated epoxy resins, plastics, and heavy metals (lead, mercury, and cadmium). Direct burning and landfilling of WPCBs may cause severe health issues and impair the environment. Therefore, sustainable treatment of WPCBs is necessary to recover valuable metals and remove hazardous materials before disposal. The present work investigates the separation of copper-rich metallic fractions from the WPCBs by the combination of hammer milling and ultrasonic irradiation. Initially, discarded mobile phone PCBs are pre-processed and shortened into 1 × 1 cm2. Downscaled WPCBs are fed into the hammer mill to obtain the fine ground powder. The Powdered WPCBs are further processed through ultrasonic treatment to acquire metal-rich fraction. XRD, SEM-EDS, and ICP/AAS analysis revealed that the current technique can efficiently separate the metal-rich fraction without using toxic solvents. Results show the enhancement of copper fraction from 42.73 to 87 wt. % after ultrasonic treatment of WPCBs ground powder. Further, nitric acid leaching has been implemented to metal-rich fractions, and the parameters have been optimized for copper leaching with the assistance of response surface methodology (RSM) of the design of experiments (DOE). Quantitative dissolution (98.96%) of copper occurred using 3.5M nitric acid within 3h at 30°C with 50 GPL pulp density and 500rpm agitation speed. Finally, the kinetics of the leaching process were studied to conform the kinetics model. Moreover, the activation energy for diffusion (19.075kJ/mole) and reaction kinetics model (13.29kJ/mole) has also been calculated. The low energy consumption due to room temperature pre-treatment and effective leaching ensures the industrial feasibility of the proposed process.

Governing of the piezoelectric effect by external fields and strains

Piezoelectricity in quantum rare-earth metallic boron oxides with the coupling between magnetic, electric and elastic subsystem is studied theoretically. It is proved that the change of piezoelectric modules of the considered crystals are proportional to components of the quadrupole susceptibility, which determines the external magnetic and electric fields, strain and temperature dependences of that change. We show why holmium compounds manifest the strongest renormalization among other rare-earth ions in this family of crystals. The reason is in the structure of the low energy term of the electron configuration, depending on spins and orbital moments of 4f electrons.

Ni–P–PTFE cathode with low surface energy for enhancing electrochemical water softening performance

ABSTRACT Efficient cathode regeneration is a significant challenge in the electrochemical water softening process. This work explores the use of an electroless plating Ni–P–PTFE electrode with low surface energy for this purpose. The Ni–P–PTFE electrode demonstrates improved self-cleaning performance at high current densities. By combining the low surface energy of the electrode with fluid flushing shear force, the precipitation rate on the Ni–P–PTFE electrode remains stable at approximately 18 g/m2·h over extended periods of operation. Additionally, the cleaning efficiency of the Ni–P–PTFE electrode surpasses that of stainless steel by 66.34%. The Ni–P–PTFE electrode can maintain a larger active area and a longer operational lifespan is attributed to its self-cleaning performance derived from low surface energy. Furthermore, the loose scale layers on the electrode surface are easily removed during electrochemical water softening processes, presenting a novel approach to cathode surface design.

Repurposing coal plants into thermal energy storage—a techno-economic assessment in the Indian context

Abstract Substantial coal phase out initiatives have been growing as the world mobilizes to meet the Paris climate goals. However, the stranded asset risk associated with this critical transition could fall disproportionately on Asian economies with younger coal fleets, like India. Here, we undertake plant-level techno-economic analysis to explore the value of installing commercially available, molten-salt thermal energy storage (TES) systems for repurposing existing coal power plants in the Indian context. We combine process simulation and an economic optimization model to evaluate design and operations of TES systems for a variety of technology assumptions, coal plant archetypes, and electricity price scenarios. Key drivers of economic viability identified include longer remaining plant lifetime, increasing peak TES temperature, lower TES energy capacity cost, co-production of waste heat for end-uses, and increasing temporal variability of electricity prices. The plant-level analysis was then extended to screen for the potential of TES retrofits within the coal power fleet in Uttar Pradesh, the most populous Indian state with a significant share of India’s coal capacity. Analysis for a single electricity price scenario indicates that over 82% of the coal units in the state can be retrofitted and recover the installed costs of TES retrofits, provided that fixed operating and maintenance costs are excluded. These results reinforce the opportunity for decision-makers to consider TES retrofits of coal plants into cost-effective grid decarbonization strategies.

Location preference of boron and nitrogen dopants at graphene/copper interface

Controlling the placement of dopants can significantly tailor graphene's properties, but this process is influenced by copper substrates during vapor deposition. Understanding the influence of interfacial atomic structures on the preference for dopant locations is crucial. In this work, we conducted a systematic first-principles study of boron- and nitrogen-doped graphene on copper {111}, considering both sublattice and superlattice configurations. Our calculations revealed that the formation energy is minimized at the top-fccb site (−0.60 eV) for boron and the hcp-fcca site (1.94 eV) for nitrogen, suggesting a possible selective distribution of dopants in both sublattice and superlattice arrangements at the graphene/copper interface. Furthermore, a lower formation energy indicates a higher release of energy during doping, resulting in a stronger interfacial binding. Since formation energy is closely associated with out-of-plane interactions, while in-plane interactions remain relatively stable, these differences offer potential avenues for modifying dopant distribution at graphene/copper interfaces.

Gender Difference in the Impact of Total Energy Intake on the Association between Low Fiber Intake and Mental Health in Middle-Aged and Older Adults

The effect of dietary fiber intake on mental health is controversial. This study aimed to examine the association of fiber intake with mental health in Korean adults. This cross-sectional study included 11,288 participants aged ≥40 years who participated in the Korean Genome and Epidemiology Study (2004–2013). Fiber intake was assessed using a food frequency questionnaire and categorized into sex-specific quintiles. Multiple logistic regression models were used to investigate the association between the lowest quintile of fiber intake and poor mental health. Mental health was assessed using acute stress perception, the Psychosocial Well-Being Index-Short Form, self-rated health, and the Center for Epidemiological Studies–Depression Scale in Korea. Compared to those with higher fiber intake, having the lowest quintile of fiber intake was associated with higher odds of poor mental health risk, a higher risk of high-stress perception, poor psychosocial distress in males, poor psychosocial distress, and depression in females. Low fiber intake had profound negative mental health effects on males with high total energy intake and females with low total energy intake. In conclusion, there is a gender difference in the impact of total energy intake on the deleterious effect of low fiber intake on mental health.

Thionation‐Induced Enhancement of Optical and Electronic Properties in NDI Molecule for Molecular Electronic Applications: A Computational Study Using DFT/TD‐DFT and QTAIM Theory

AbstractThe study investigates the impact of thionation on N,N'‐di(dodecyl)‐4,5,8,9‐naphthalene diimide (NDI) through computational methods such as density functional theory (DFT/TD‐DFT), quantum theory of atoms in molecules (QTAIM), and Landauer theory (LT). Thionation, involving the replacement of diamide oxygens with sulfurs in NDI, significantly enhances quantum‐electronic/thermoelectric properties. Computational analyzes of energy of frontier orbitals HOMO/LUMO, dipole moment, polarizability, first superpolarizability, UV spectrum, and cohesive energy show the superior performance of the thione structure (M2) compared to the pristine structure (M1). Thionation decreased the energy gap from 01.3 eV (in M1 structure) to 1.87 eV (in M2 structure). The absorption wavelength in the pristine structure (M1) is calculated to be 507 nm, which increased to 1067 nm after thionation (M2). Cohesive energy values for each of M1 and M2 structures are calculated as 12.76 and 12.89 Kcal mol−1, respectively, which indicates the improvement of stability after thionation. After connecting M1 and M2 to gold electrodes (Au‐M1‐Au and Au‐M2‐Au) and applying electric fields, the Au‐M2‐Au structure shows a lower energy gap, lower thermoelectric activity and higher conductivity at field intensities with higher than 140 × 10−4 (a.u.), indicating its use as a field‐effect molecular device (such as molecular wire or molecular switch).

Semi-active control implementation in aircraft landing gear systems using hardware-in-the-loop test bench

In small-sized aircraft landing gear systems, magnetorheological (MR) dampers offer an innovative approach to adjusting damping levels under wide range of operating situations in order to achieve competing control objectives such as ride comfort, suspension travel, and energy consumption. Also, MR dampers have nonlinear dynamics and exhibit hysteresis. In this context, this paper aims to present a Hardware-In-the-Loop (HIL) technique for the implementation of backstepping control and linear quadratic regulator (LQR) control. Experimental results highlight that, compared to passive suspension (Passive Off), backstepping control and LQR control approaches reduce the fuselage vertical acceleration by 29.13% and 24.95%, respectively. Moreover, the ISO 2631 standard was adopted to evaluate ride comfort. LQR control can able to minimize the fuselage roll acceleration under a random road profile. Also, LQR control provides the highest performance in terms of fuselage roll acceleration, achieving a 6.2% improvement with lower energy consumption. By utilizing HIL, semi-active control methods can be tested and developed without the need for the aircraft, while keeping the characteristics that the physical aircraft would bring.

Thermodynamic modeling and analysis of a Carnot battery system integrating calcium looping thermochemical energy storage with coal-fired power plant

Long-term energy storage and carbon capture technologies are pivotal in managing renewable energy surpluses and achieving carbon neutrality. This paper proposes a Carnot battery system integrating calcium-looping thermochemical energy storage with a coal-fired power plant. The system utilizes excess electricity from the grid for energy input, facilitating long-term energy storage, achieving carbon capture, and reducing coal consumption in the power plant. An optimization framework is developed, incorporating component thermodynamic models and optimization algorithms, to maximize the coal savings in plants and energy efficiencies of the Carnot battery system. During the energy release process, the carbonator partially replaces the reheat load of the boiler, necessitating retrofitting of the boiler’s heating surface to ensure normal operation. The base system demonstrates a CO2 capture capacity of 3.23 MJ/kg and a reduction in coal consumption by 7.07 %. The round-trip efficiency and comprehensive efficiency of the base system are 36.93 % and 37.91 %, respectively. The relatively low energy efficiency is primarily due to the deactivation of circulating adsorbents and the limited efficiency of the subcritical coal-fired power plant. By incorporating an additional recarbonation step to mitigate adsorbent deactivation, the system’s comprehensive efficiency is improved to 42.20 %. Further improvements in system efficiency can be achieved by using modified adsorbents with high cycling stability instead of natural limestone and by coupling the system with more efficient ultra-supercritical units instead of the investigated subcritical units. This study offers valuable insights into the development of long-term energy storage solutions and multifunctional Carnot battery technology.