Ionics最新文献

With the gradual transformation of energy industries around the world, the trend of industrial reform led by clean energy has become increasingly apparent. As a critical link in the new energy industry chain, lithium-ion (Li-ion) battery energy storage system plays an irreplaceable role. Accurate estimation of Li-ion battery states, especially state of charge (SOC) and state of health (SOH), is the core to realize the safe and efficient utilization of energy storage systems. This paper presents a systematic and comprehensive evaluation and summary of the most advanced Li-ion battery state estimation methods proposed in the past 3 years, focusing on analyzing data-driven state estimation algorithms. At the same time, the latest Li-ion battery data sets and data selection methods are analyzed, and future research trends and possible challenges are proposed. This review will provide a valuable reference for future academic research in Li-ion battery state estimation.

Rechargeable magnesium batteries (RMBs) represent a promising beyond-lithium technology for energy storage due to their high energy and power densities. However, developing suitable electrolytes compatible with both electrodes and exhibiting high thermal and electrochemical stabilities remains a significant challenge for RMBs. In this study, we present the development of a novel electrolyte for RMBs based on a eutectic mixture of 1-ethyl-3-methylimidazolium chloride and 1-ethyl-3-methylimidazolium hexafluorophosphate. This electrolyte demonstrates a high ionic conductivity of ~ 6.7 mS.cm⁻¹ at room temperature and a wide electrochemical stability window (> 4.5 V vs. Mg/Mg²⁺). We demonstrate that the present electrolyte enables the reversible operation of an Mg-graphite cell with a discharge capacity of ~ 120 mAh.g⁻¹ for over 500 cycles while maintaining a Coulombic efficiency of > 95%. Furthermore, the distinctive dual-ion transport behavior of the electrolyte is substantiated through the fabrication of a symmetric graphite cell, where both anions and cations exhibit bidirectional movement during the charge and discharge processes. This cell manifests an equivalent discharge capacity to that of Mg-graphite cells. These findings underscore the potential of further optimizing RMBs utilizing this electrolyte, offering prospects for superior energy density and enhanced performance across diverse application domains.

Activated carbon fibers (ACFs) were synthesized using a straightforward two-step process from dryer lint microfibers in a self-generated atmosphere. During pyrolysis and activation, a CO/CO₂ environment was created based on the Boudouard equilibrium. The resulting ACFs showed a high specific surface area (1720 m²/g), a suitable pore size distribution, and good electrical conductivity (0.34–0.36 S/cm), promoting rapid ion transfer. ACFs demonstrated a high specific capacitance of 156.2 at 0.9 V and 180.3 F/g at 1 V. Notably, ACFs demonstrated outstanding rate capability with a power density exceeding 35 kW/kg, along with an extended cycle life of at least charge/discharge 10⁴ cycles. These results are comparable to methods involving tube furnaces under inert gas with controlled heating ramps.

This work focuses on surface modification of an innovative anionic chelating support derived from discarded polyacrylonitrile fiber (PANF) waste. The approach involves transforming nitrile groups into N,N-dicarboxymethyl amide groups through surface functionalization. Key operational parameters such as pH, temperature, chelating agent concentration, and reaction time were systematically optimized using JMP experimental design methodology. The study’s results affirm the success of the functionalization process, showcasing the efficient conversion of nitrile groups into iminodiacetic groups. Significantly, the findings underscore the economic feasibility of generating a novel chelating fiber through surface modification. The achieved optimal conversion rate for nitrile groups was approximately 81.4%, with pH, reaction temperature, and time identified as influential factors. The optimal conditions were determined as a pH of 10, a temperature of 70 °C, and a reaction time of 60 min. Additionally, comprehensive characterization revealed improved thermal stability resulting from the modification process utilizing the monochloroacetic acid (MCA) chelating agent. The study further explored the structural and thermal properties of the produced adsorbent. Measurements of ion exchange capacity confirmed the successful incorporation of additional carboxylic groups on the functionalized polyacrylonitrile fiber waste (PANF_F), reaching a maximum value of 7.55 meq/g. This is notably higher than the 0.89 meq/g observed for pure polyacrylonitrile fiber (PANF) waste.

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Poly(vinylidene fluoride) (PVDF) polymers have garnered significant interest due to their dielectric tunability and applications in micro-electric high-power systems. However, the relationship between structure and energy storage performance is not yet fully illustrated, particularly regarding the fabrication process. Herein, the influence of hot-pressing temperature on the structural and electrical properties were systematically studied, and the optimal temperature was also determined. PVDF films after hot-pressing at 150 ℃ exhibited a high discharged energy density (ESD) of 19.24 J/cm³, coupled with a large breakdown strength (E_b) of 604.08 kV/mm and a high efficiency (η) of 68.99%. The primary contribution to the improved ESD originates from the enhanced crystallinity resulting from the formation of more α-phase and γ-phase structures. Concurrently, the decrease in defects can also promote the enhancement of breakdown strength. This work can provide valuable insights into the optimization of the fabrication process to achieve superior energy storage performance in PVDF films.

The multi-cell coupling method is an effective way to solve the dynamic response problem of fuel cell power systems. However, it needs to control the stable output voltage to extend the service life of the power supply system. This article uses a PID controller to model and analyze proton exchange membrane fuel cells (PEMFCs). A lithium-sulfur battery (Li–S battery) model was established, and the discharge process of the lithium-sulfur battery was accurately simulated using the method of minimizing prediction error. These models are coupled through DC/DC boost converters to achieve a collaborative power supply system. The results indicate that the output voltage of the fuel cell is effectively stabilized at 24 V. The output voltage of the lithium-sulfur battery pack is designed to be 44–50 V. Each individual battery voltage is balanced to achieve a stable output voltage of 48 V. The system is powered by a proton exchange membrane fuel cell stack as the main power source and a lithium-sulfur battery pack as the auxiliary power source. At room temperature of 23 °C, the output voltage of the system can be stabilized within a controllable range of 48 V. Based on the operational characteristics and power demand analysis of the target ship, the basis for constructing a dual power source energy management strategy is elaborated. On this basis, fuzzy control was designed with ship demand power and lithium battery SOC as inputs and lithium battery output power as system output. An improved state flow controller was constructed by adding a ship demand power limiting unit to the logic threshold strategy that originally only had lithium battery SOC as the threshold.

These days, biopolymers are utilized significantly more often than other synthetic polymers because of the benefits they offer, which include non-toxicity, biodegradability, and renewability. The primary objective of the current work is to fabricate pectin-based biopolymer electrolytes containing magnesium triflate salt (MgTf₂) for use in electrochemical devices. Biopolymer electrolytes of pectin with MgTf₂ were synthesized by solution-casting method and are analyzed by XRD, DSC, TGA, SEM, AC impedance, FTIR, LSV, and CV techniques. The ionic conductivities of the samples were determined by AC impedance analysis, and the highest conductivity has been obtained as 4.511 × 10⁻³ S cm⁻¹ for 50 M wt% pectin: 50 M wt% MgTf₂. The total ionic transference number and Mg²⁺ transference number were found to be 0.99 and 0.315, respectively, for the highest-conducting sample. The electrochemical stability of 2.3 V has been obtained by linear sweep voltammetry (LSV) analysis for the highest-conducting electrolyte. A primary magnesium battery has been constructed with the highest conducting sample, and the open circuit voltage of the battery is 2.05 V.

A biopolymer derived from Jatropha oil-based poly(ethyl carbamate) (PUA) has been used as gel polymer electrolyte (GPE) in optoelectronic devices and photoelectrochemical cells (PEC) as photodiode devices. The quasi-solid-state photodiode device was characterized through photo current–voltage analysis, photogenerated charge carrier dynamic analysis, electrochemical impedance spectroscopy (EIS) analysis, and voltammetry analysis. Sample A2 biopolymer electrolyte (95 wt.% PUA, 5 wt.% LiI, 5 wt.% I₂) revealed the highest ionic conductivity (2.34 ± 0.01) × 10⁻⁴ S cm⁻¹ and power conversion efficiency (5.09 ± 0.23) %, along with the highest short-circuit current density (17.80 ± 0.41) mA cm⁻², open-circuit voltage (0.52 ± 0.01) V, and fill factor (0.55 ± 0.04). respectively. Moreover, sample A2 biopolymer electrolyte featuring a triiodide ion diffusivity of 1.82 × 10⁻⁸ cm² s⁻¹ demonstrated electrochemical stability up to 2.1 V and remained functional for a duration of 2000 cycles. The charge dynamic mechanism in the PEC proved that sample A2 biopolymer electrolyte recorded lowest values of R_s, R_pt, R_ct, and R_d of (18.60 ± 0.01) Ω, (1.20 ± 0.01) Ω, (10.0 ± 0.01) Ω, and (11.50 ± 0.01) Ω, respectively.

Using coal-based polyaniline as a carbon source and nitrogen source, nitrogen-doped carbon nanotubes (NCNTs) were successfully prepared through a two-stage furnace process. The PtPd/NCNTs catalysts were synthesized by the ethylene glycol reduction method. The results of transmission electron microscopy (TEM) show that the PtPd nanoparticles with an averaged diameter of 3.1 ± 0.5 nm uniformly support the surface of NCNTs. The X-ray photoelectron spectroscopy (XPS) reveals that nitrogen mainly exists in graphite states in NCNTs. The electrocatalytic activity of the PtPd/NCNTs catalyst was tested by CO stripping voltammetry, cyclic voltammetry (CV), and chronoamperometry (CA). The electrochemical characterization shows that the PtPd/NCNTs catalyst exhibited higher electrocatalytic activity and stability towards formic acid oxidation. At the same time, its forward peak current density (549.83 mA mg⁻¹) is 4.5 times higher than that of PtPd/CNTs (120.90 mA mg⁻¹). The developed NCNTs are highly promising catalyst supports for direct formic acid fuel cells.

A porous structure of copolymer poly (aniline-co–o-phenylenediamine) has been fabricated by chemical oxidation process with nonionic surfactant Triton X-100. Different ratios of monomers (1:9, 5:5 and 9:1) have been utilized; structure and surface morphology has been analyzed by FTIR and SEM–EDX techniques. The UV, XRD and BET surface area measurement were also done. The electrochemical techniques such as cyclic voltammetry and electrochemical impedance were used to evaluate electrochemical capacitance performances. The copolymer comprising equimolar mixture of monomers displayed high surface area that helps to amplify the diffusion of electrolyte ions. Hence, the specific capacitance of developed copolymer has been determined as 989 F g⁻¹ at 5 mA cm⁻² current density from galvanostatic charge–discharge studies with retainability of 84.94% capacitance after 100 cycles.

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