Ionics最新文献

Supercapacitors have emerged today as a compelling choice in the realm of renewable and clean energy storage. They possess several outstanding features such as high-power density, quick charging/discharging, long-cycle life, safety, and environment friendliness. These features make them an attractive option for a wide range of applications, including renewable energy systems, transportation, consumer electronics, energy harvesting, medical, aerospace, and defense. However, supercapacitors suffer from some limitations, such as low-energy density compared to alternative energy storage technologies like lithium-ion batteries. Through meticulous selection and optimization of electrode materials, it is possible to tackle this challenge while simultaneously enhancing the energy storage capacity and preserving their other favorable characteristics. Thus, the choice of electrode materials plays a decisive role in determining the overall performance of supercapacitors. In this review paper, an elaborate description of the technologies, operational principles, and recent progress behind the two significant transition metal oxides, namely RuO₂ and MnO₂, along with their integration with PANi, a crucial conducting polymer, employed as electrode materials in supercapacitors, are presented. The performance of these nanocomposite electrode materials with a primary consideration on their binary forms has been analyzed and reviewed by the parameters like energy density, power density, specific capacitance, cyclic performance, and rate capability. Detailed discussion is made regarding the structure of the materials prepared using varied synthesis processes with special focus on the morphology and capacitance values, future prospects, and how do they align with the desired performance attributes.

A novel polymer gel electrolyte (PGE) system containing potassium perchlorate (KClO₄) and poly(vinylidene fluoride-co-hexafluoropropylene) (PVdF-HFP) incorporated with various concentrations of 1-ethyl-3-methylimidazolium tetrafluoroborate (EMIMBF₄) and tetraethylene glycol dimethyl ether (TEGDME) as molecular solvents is reported. Impedance measurements revealed that the PGE film with higher content of EMIMBF₄ ionic liquid provides an excellent room-temperature ionic conductivity of ~ 2.36 × 10⁻² S cm⁻¹, relatively low activation energy of ~ 0.18 eV, and notably higher electrochemical stability window of ~ 3.5 V. The optimal PGE demonstrates gel-phase retention for a wide temperature range and maintains thermal stability up to 112 °C. The infrared spectroscopy studies reveal the interactions of electrolyte ions with the polymer matrix. The possible structural and morphological variations in polymer matrix owing to the addition of TEGDME and EMIMBF₄ solution have been explored by X-ray diffraction (XRD) and scanning electron microscopic (SEM) study. The UV–visible spectroscopy depicts the rise in absorption and decline in the optical band gap on incorporation of salt and molecular solvent.

Concentration (n), mobility (µ), and diffusivity (D) of charge carriers are the three main properties that profoundly influence not only the ionic conductivity but also the overall performance of solid polymer electrolytes (SPEs). In this work, SPEs incorporating gellan gum (GG) as the host polymer and varying concentrations of sodium trifluoromethanesulfonate, NaCF₃SO₃ (10 to 50 wt.%), were prepared using the solution casting technique. The characteristics of n, µ, and D within the electrolyte samples at room temperature were determined by evaluating the Nyquist plot with equations derived from an electrical equivalent circuit. The conductivity started at (4.27 ± 0.29) × 10⁻⁸ S cm⁻¹ for the free-salt sample (L0 electrolyte) and gradually increased to an optimal value of (1.06 ± 0.99) × 10⁻⁶ S cm⁻¹ in the sample containing 40 wt.% NaCF₃SO₃ (L4 electrolyte). Increasing the NaCF₃SO₃ concentration from 10 to 40 wt.% in GG led to an increase in n from (6.81 ± 0.03) × 10¹⁶ cm⁻³ to (5.61 ± 0.31) × 10¹⁸ cm⁻³ due to enhanced ion dissociation. Conversely, the µ and D decreased from (1.15 ± 0.03) × 10⁻⁵ cm² V⁻¹ s⁻² to (1.19 ± 0.05) × 10⁻⁶ cm² V⁻¹ s⁻² and from (2.97 ± 0.08) × 10⁻⁷ cm² s⁻¹ to (3.06 ± 0.13) × 10⁻⁸ cm² s⁻¹, respectively, attributed to increased collisions between free ions. The value of Stokes drag coefficient (F_d) increased from (1.40 ± 0.02) × 10⁻¹⁴ kg s⁻¹ to (1.35 ± 0.05) × 10⁻¹³ kg s⁻¹ due to the low charge carriers mobility in the electrolyte system. Although the L4 electrolyte exhibits low conductivity at room temperature, its conductivity increased by three orders of magnitude to 1.87 × 10⁻³ S cm⁻¹ at 75 °C, highlighting its potential as a promising natural-based polymer electrolyte. This work provides a detail mechanism of charge transport that influences the conductivity variation within the natural-based polymer electrolyte system, offering important insights for fundamental understanding.

A comparison of the effect of microstructure on the lithium storage about two series of soft carbon was investigated. Refined pitch soft carbon (RPC) and modified mesophase pitch soft carbon (MPC) were obtained by adjusting the heat treatment temperature (900–1400 °C). The microcrystalline morphology of soft carbon in carbonization process is determined by the structure and composition of feedstocks, which may be attributed to the molecular flatness and the order of molecular cluster accumulation. Interestingly, the 1000℃ appears to be the inflection point for the growth change of carbon microcrystals in the carbonization process of RPC and MPC materials. The results found that MPCs show better cyclic stability and initial Coulombic efficiency (ICE) compared with RPCs. Specifically, MPC-1000 exhibit 278.6 mA h g⁻¹ at 100 mA g⁻¹ after 300 cycles, high retention rate 74.3%, and high ICE 70.2%, resulting in the main inserting lithium storage from ordered carbon microcrystals and fewer defects and pores. RPC-1000 anode shows higher specific capacity 283.7 mA h g⁻¹ at 100 mA g⁻¹ after 300 cycles, retention rate 67.1%, and ICE 66.5%, due to the main adsorption lithium storage from the balance of smaller carbon microcrystals and pore structure. In particular, both MPC-1000 and RPC-1000 showed excellent high-rate properties 206.1 and 214.5 mA h g⁻¹ at 2000 mA g⁻¹, respectively. This study explores the influence of soft carbon microstructure on electrochemical properties, from the feedstock molecular structure to the order carbon microcrystals, providing a reference to obtain pitch-based soft carbon anodes with high compatibility.

High-performance polymeric separators are indispensable materials for advanced rechargeable lithium-ion batteries (LIBs). In general, separators must simultaneously possess the following qualifications: flame retardancy, mechanical strength, wettability, and ion conductivity. In this study, polyethylenimide (PEI), which is rich in amino groups, was grafted onto the surface of polyimide fibre membranes by impregnation, resulting in the preparation of PI-PEI composite separator. The grafting of PEI on PI nanofibres resulted in the bonding of fibres, which enhanced the stability of the pore structure and mechanical properties of the nanofibres. Furthermore, the number of polar groups on the surface of the PEI grafted by the PI separator increased, which enhanced the electrolyte affinity of the PEI-PI separator. The influence of PEI concentration on the properties of the separator, electrochemical properties, and cell performances was also discussed, and the optimal PEI concentration (4%PEI) was identified. The PI-4%PEI composite separator exhibited superior wettability, mechanical strength, flame retardancy, and minimal interface impedance. In particular, PI-4%PEI separators display superior capability (127.9 mAh·g⁻¹@5C) in comparison to PP separators (115.4 mAh·g⁻¹@5C). Furthermore, the cell employing the PI-4%PEI separator displays high cycling stability and discharge specific capacity over 100 cycles at 1C. Concurrently, the modified polyimide separator exhibits remarkable stability, ensuring that the lithium-ion battery can operate safely even under high temperature working conditions.

The recycling complexity of spent alkaline zinc-manganese dry batteries contributes to environmental pollution and suboptimal resource utilization, highlighting the urgent need for the development of streamlined and efficient recycling strategies. Here, we propose to apply the regenerated cathode material of waste alkaline zinc-manganese batteries to aqueous zinc ion batteries (AZIBs), which can be directly recycled selectively in one step by a simple calcination method. The regenerated α-MnO₂ presents a regular nanowire shape with oxygen defects, applied as a cathode for the AZIBs; it can provide a specific capacity of 173.4 mAh g⁻¹ even after 2000 cycles. This simple recycling strategy for the positive electrodes of spent alkaline zinc-manganese batteries not only reduces the complexity of the recycling process of spent alkaline batteries, but also achieves the purpose of high-value recycling, significantly reducing environmental pollution and resource waste.

Lithium-ion power batteries have become integral to the advancement of new energy vehicles. However, their performance is notably compromised by excessive temperatures, a factor intricately linked to the batteries’ electrochemical properties. To optimize lithium-ion battery pack performance, it is imperative to maintain temperatures within an appropriate range, achievable through an effective cooling system. This paper delves into the heat dissipation characteristics of lithium-ion battery packs under various parameters of liquid cooling systems, employing a synergistic analysis approach. The findings demonstrate that a liquid cooling system with an initial coolant temperature of 15 °C and a flow rate of 2 L/min exhibits superior synergistic performance, effectively enhancing the cooling efficiency of the battery pack. The highest temperatures are 34.67 °C and 34.24 °C, while the field synergy angles are 79.3° and 67.9°, achieved by optimizing the initial coolant temperature and flow rate. The structure of the 10 coolant pipes has a good consistency. As the charge/discharge rate increases, battery heating power escalates, resulting in a notable rise in temperature and synergy angle. Optimal cooling efficiency is achieved with three cooling channel inlets, minimizing the temperature difference across the battery pack.

In order to determine the optimal crystalline form of manganese-based catalysts for zinc-air battery cathodes, in this paper nano-α-MnO₂ and amorphous manganese dioxide (AMO) materials were successfully synthesised by hydrothermal and liquid-phase co-precipitation methods, respectively. The results show that the spherical AMO material has larger specific surface area and more mesopores than the rod-like α-MnO₂. Moreover, AMO has abundant structural defects and short-range ordered atomic arrangements that can enhance the ion diffusion kinetics and improve the catalytic performance of the materials. Through electrochemical tests, it is found that the AMO materials have better catalytic properties compared to α-MnO₂. At a current of 10 mA/cm², its discharge-specific capacity reached 575.2 mAh/g, which is 11.1% higher than that of 517.8 mAh/g for α-MnO₂. And AMO have higher peak power density and smaller charge/discharge voltage gaps. In the long-cycle test, the initial round-trip efficiency of the electrode prepared of AMO is also better than that of α-MnO₂. However, when the AMO electrodes are charged and discharged for a long time, part of the AMO will be converted to α-MnO₂, which lead to a gradual decrease in the cycling stability of the AMO electrodes. Therefore, this paper concludes that AMO materials are superior to α-MnO₂ as catalysts for zinc-air batteries.

An excellent thermal management system (TMS) provides robust guarantee for power batteries operating under high-rate discharge conditions. Specifically designed for cylindrical battery packs, we propose a novel TMS combining phase change material (PCM) with a double-layer cold plate. To enhance the overall performance of the composite thermal management system, the performance parameters of the system are optimized and their effects are compared. Initially, the thermal performance of PCM with different thicknesses was compared, revealing that optimal comprehensive performance was achieved with a PCM thickness of 3 mm, resulting in a temperature difference of 1.52 °C. As the depth of the cold plate and the coolant flow rate increased, the temperature difference showed a tendency of decreasing and then increasing. Furthermore, the choice of PCM and coolant inlet temperature significantly influenced system performance. In particular, the use of RT31 as the phase change material with an inlet temperature of 15 °C was able to control the average temperature of the module at 34.75 °C, and the temperature difference only increased to 2.25 °C. Conversely, by using an inlet temperature of 30 °C was able to reduce the temperature difference to 1.26 °C with a liquid phase fraction of 0.96. Our findings demonstrate that the novel double-layer cold plate can effectively dissipate the heat stored in the PCM, and the designed composite system exhibits superior heat dissipation performance and temperature uniformity.

The present work is focused on the synthesis and detailed study of biopolymer phytagel and sodium thiocyanate (NaSCN)-blended polymer electrolyte films for supercapacitor applications. Here, the solution cast technique has been used to synthesize the biopolymer phytagel-based polymeric films with different concentrations of sodium thiocyanate. The prepared polymer electrolyte films are characterized for their structural, electrical, and dielectric properties using different characterization tools such as X-ray diffraction, Fourier transform infrared spectroscopy, electrochemical impedance spectroscopy, linear sweep voltammetry, and Wagner polarization technique. The film with 35wt% sodium thiocyanate shows a maximum conductivity of 6.36 × 10⁻⁴ S/cm. A laboratory scale symmetric supercapacitor device (EDLC) is fabricated using activated carbon as an electrode material and maximum conducting phytagel-based polymer electrolyte, which is further characterized using electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV). The fabricated electric double-layer capacitor shows a specific capacitance of 38.65 F/g at a scan rate of 5 mV/s.