Ionics最新文献

Dual carbon batteries (DCB) are gaining traction in energy storage research due to their cost-effectiveness, better safety, eco-friendliness, and rapid charging capability. Despite these merits, carbon-based electrode systems face many challenges, particularly in their relatively lower energy density. Researchers are addressing this by exploring innovative strategies, with a focus on electrolyte additives. One noteworthy additive is ethylene sulfite (ES), recognized for its protective effect on electrodes. This study compares two LiTFSI-based electrolytes, one of which is enhanced with ES, to determine their potential in improving DCB capabilities. The LiTFSI-ES electrolyte demonstrates a higher conductivity (7.29 × 10⁻³ S cm⁻¹) and a broader potential window (5.554 V) compared to LiTFSI alone. Cyclic voltammetry (CV) and dQ/dV analysis confirm the intercalation of TFSI⁻ anions in the graphite electrode, indicating DCB behavior. This research contributes valuable insights into enhancing DCB performance through the incorporation of ES and sheds light on the electrochemical behavior of the LiTFSI-ES electrolyte.

Accurate state of charge (SOC) estimation of lithium-ion batteries can effectively help battery management system better manage the charging and discharging process of batteries, providing important reference basis for the use planning of power vehicles. In this paper, an improved chaotic particle butterfly optimization-cubature Kalman filtering (CPBO-CKF) algorithm is proposed for accurate SOC estimation of lithium-ion batteries. Considering the hysteresis characteristics and polarization effects, an improved hysteresis characteristics-dual polarization (HC-DP) equivalent circuit model is established, which can more accurately characterize the internal characteristics of battery. To achieve high-precision SOC estimation, an improved chaotic particle butterfly optimization algorithm is introduced for dynamic optimization of noise in the cubature Kalman filtering algorithm, and the proposed CPBO-CKF algorithm can more accurately describe the actual noise characteristics, thereby reducing estimation errors. The proposed algorithm is validated under complex working conditions at different temperatures, and the results show that it has good accuracy. Under BBDST condition at 15 °C, 25 °C, and 35 °C, the mean absolute errors (MAEs) are 0.80%, 0.56%, and 0.71%, while the root mean square errors (RMSEs) are 1.09%, 0.70%, and 0.88%. Under DST condition, the MAEs are 0.73%, 0.49%, and 0.52%, and the RMSEs are 0.86%, 0.67%, and 0.63%.

A series of ether-functionalized paramagnetic ionic liquids, 1-(2-methoxyethyl)-3-alkylimidazolium tetra thiocyanate cobalt [C_n2O1IM]₂[Co(NCS)₄] (n = 1, 2, 3), was synthesized and characterized. The density, surface tension, refractive index, and electrical conductivity of these ionic liquids were measured at 293.15 to 343.15 K at intervals of 5 K, and their thermal expansion coefficients α were calculated. The molecular volume was obtained by measuring the pore volume and porosity. Based on Glasser theory, the standard entropy S₀ (298 K), lattice energy U_POT, surface entropy S_a, and surface enthalpy, H of the ionic liquids were calculated, and the reason why the ionic liquid is in a molten state at room temperature was explained from the perspective of lattice energy. The molar surface Gibbs energy was introduced to improve the traditional Eötvös equation, which was combined with the refractive index to estimate the surface tension, obtaining a fitting index exceeding 0.99. Finally, the relationship between the electrical conductivity of the ionic liquids and temperature was investigated, and the activation energy, molar electrical conductivity, and electrical conductivity diffusion coefficient of the ionic liquids were obtained. The relationship between their properties was summarized. Compared with previously reported ionic liquids using 1-(2-methoxyethyl)-3-methylimidazolium as a cation, this type of ionic liquid has higher density and a smaller coefficient of thermal expansion.

Lithium-ion conducting solid polymer electrolytes are prepared by incorporating lithium triflate (LiCF₃SO₃) salt into a plasticized blend of Iota-carrageenan and acacia gum, using the solution casting method. The structural and molecular complexations of the resulting electrolytes are analyzed through X-ray diffraction and Fourier-transform infrared analysis. AC impedance analysis spectra demonstrate that the addition of 33 wt.% of LiCF₃SO₃ salt into the polymer electrolyte blend (IATF50) results in higher ionic conductivity of 3.18 × 10⁻³ S/cm, and a minimum activation energy of 0.03 eV. The highly conductive electrolyte follows the overlapping-large polaron tunnelling (OLPT) paradigm. The dielectric and modulus spectra further confirm the non-Debye nature of the electrolyte. From the transference number measurement, it is confirmed that the conductivity is mostly due to Li ions and the IATF50 sample is chosen to fabricate a symmetrical supercapacitor. Galvanostatic charge/discharge studies show the discharge characteristics with a duration of 30 s and a specific capacitance (C_s) value of 100 F/g.

Free standing nanocomposite polymer electrolytes (NCPEs) based on the polymer host poly(vinyl) chloride (PVC) were successfully prepared using the solution casting technique. Lithium nitrate (LiNO₃) and nano-sized silica (SiO₂) (< 100 nm) were employed as the electrolyte and filler, respectively. Impedance studies revealed a maximum ionic conductivity value of 1.226 × 10⁻⁴ S/cm at room temperature for the PVC/LiNO₃ with 5 wt.% nano-SiO₂. X-ray diffraction (XRD) analysis verified the sample’s amorphous nature. Dielectric permittivity and relaxation time values were consistent with impedance results. Additionally, parameters such as diffusion coefficient, mobile concentration, and mobility were evaluated for the prepared samples. Differential scanning calorimetry (DSC) studies confirmed a change in glass transition temperature (T_g) of PVC/LiNO₃/SiO₂ sample. The scanning electron micrograph (SEM) images revealed a honeycomb morphology, indicating ease of Li⁺ ion transportation.

The performance of fuel cells is greatly influenced by the design of the flow channels, making it one of the most significant factors impacting their overall performance. In this work, numerical simulations on serpentine, parallel, and interdigitated geometries are carried out using an open-source toolbox at 0.5, 0.4, and 0.3 V to observe the liquid water saturation distribution at the cathode side of a three-dimensional multiphase non-isothermal model of a protonic exchange membrane fuel cell. The results indicate that the serpentine flow channel shows the maximum current density and the minimum saturation distribution. Also, it is shown that maximum saturation values are located at the edges of the membrane-electrode assembly. There is an important change in the ionic distribution which directly impacts the current density.

Graphical Abstract

Tributyl borate (TBB) is among the widely used film-forming electrolyte additives in lithium-ion batteries (LIBs). It possesses the capability to produce an inorganic solid electrolyte interphase with abundant polar boron-containing compounds, functioning as a solid electrolyte interlayer (or cathode electrolyte interlayer), thus effectively isolating the electrode material from the electrolyte and averting parasitic reactions. Herein, the TBB could contribute to the formation of an inorganic solid electrolyte interphase rich in polar B-F and B-O bonds, thus enhancing the stability of the interface between the electrolyte and cathode materials. The findings demonstrate that the inclusion of 0.5 wt% TBB significantly enhances the stability of the electrode/electrolyte interface in Li‖LiMn_0.8Fe_0.2PO₄ batteries. After 600 cycles, the specific capacity reaches 107.9 mAh g⁻¹ with a capacity retention of 86.45%. This indicates outstanding electrochemical performance and excellent cycling stability. Consequently, TBB exhibits potential as an electrolyte additive for future high-energy density lithium batteries.

Estimation of Urbach energy profiles and tailoring the structural and optical properties of semiconducting materials as photocatalysts can be helpful for the effective treatment of wastewater. In this aspect, pure SrFe₁₂O₁₉ and Cu/Gd@SrFe₁₂O₁₉ were synthesized via co-precipitation route, and carbon nanotubes (CNTs)-based composite of Cu/Gd@SrFe₁₂O₁₉ was synthesized by an ultra-sonication method. The structural analysis of all prepared samples showed a considerable decrease in crystallite size (13.8 nm) for Cu/Gd@SrFe₁₂O₁₉/CNTs nanocomposite as compared to pure SrFe₁₂O₁₉ (20 nm). The bandgap energy of Cu/Gd@SrFe₁₂O₁₉ was decreased to 2.43 eV as compared to SrFe₁₂O₁₉ (2.64 eV), and Urbach energy of Cu/Gd@SrFe₁₂O₁₉/CNTs composite was increased to 1.85 eV as compared to SrFe₁₂O₁₉ (1.56 eV) and Cu/Gd@SrFe₁₂O₁₉ (1.63 eV). Moreover, the results obtained from photoluminescence (PL) spectroscopy revealed that the CNTs-based photocatalyst exhibited less electron/hole pair recombination rate as compared to its other counter parts that was further confirmed by its improved photocatalytic efficiency. The photocatalytic activity of SrFe₁₂O₁₉, Cu/Gd@SrFe₁₂O₁₉, and Cu/Gd@SrFe₁₂O₁₉/CNTs composite was determined against bromocresol blue (BCB) and methyl orange (MO) under solar light irradiation of about 60 min. The as fabricated SrFe₁₂O₁₉, Cu/Gd@SrFe₁₂O₁₉, and Cu/Gd@SrFe₁₂O₁₉/CNTs showed about 68%, 79%, and 87.6% degradation of BCB, respectively. In addition, about 65%, 79%, and 92% degradation of MO was observed by SrFe₁₂O₁₉, Cu/Gd@SrFe₁₂O₁₉, and Cu/Gd@SrFe₁₂O₁₉/CNTs, respectively. The estimated results deduce that the outstanding photocatalytic activity of a novel nanocomposite (Cu/Gd@SrFe₁₂O₁₉/CNTs) for both BCB and MO is accredited to the combined effect of narrow bandgap of co-doped SrFe₁₂O₁₉ and high specific surface area, small crystallite size, and high charge separation ability of MWCNTs. Hence, Cu/Gd@SrFe₁₂O₁₉/CNTs composite could be an efficient photocatalyst for the degradation of various harmful pollutants.

Graphical Abstract

Bismuth microspheres@N-doped porous carbon anode (Bi@NPC-2) is rational designed and successfully prepared by an easy one-pot heat treatment process. The composite demonstrated superior sodium storage performance, including excellent cyclic stability of 326.4 mAh g⁻¹ after 4000 cycles at 5 A g⁻¹ with a capacity retention of 95% and ultra-high rate capability of 286.7 mAh g⁻¹ at a high current rate of 40 A g⁻¹. This excellent performance is mainly due to the unique material design, the three-dimensional porous structure not only helps to mitigate the volume expansion of bismuth, but also shortens the diffusion path of sodium ions. In addition, nitrogen doping improves the conductivity of the electrode and provides more active sites for sodium storage. More importantly, the preparation process is simple, and the raw materials used are cheap, thus the Bismuth microspheres@N-doped porous carbon composite shows important practical large-scale applications. This one-step sintering method can also be applied to other alloy-based sodium storage materials.

Niobium-based phosphates have the advantages of high stability and environmental protection and have good application prospects in sodium-ion batteries. The pure phase of Na(NbO₂)₂PO₄ (NNP) powder was successfully synthesized by different methods in this work, and the materials were characterized via XRD, XPS, SEM, and electrochemical methods. At the current density of 100 mA g⁻¹, the discharge-specific capacity of NNP is 521.8 mAh g⁻¹ in the first cycle and remains at 462.4 mAh g⁻¹ after 200 cycles, indicating that it has good cycling stability. The kinetic results obtained from cyclic voltammetry (CV) show the pseudo-capacitance contribution accounts for a large percentage of the capacity. The charge transfer resistance of NNP is 260.3 Ω, which is significantly smaller than the others derived from electrochemical impedance spectroscopy (EIS). These pointed to the advantages of NNP in anode material for SIBs.