Journal of Power Sources Advances最新文献

The need for high-energy and safe batteries is more and more urgent, and a possible approach is to use solid polymer electrolyte with high conductivity combined with lithium metal anode. Poly (1,3-dioxolane)-based electrolytes are promising, and the feasibility to polymerize 1,3-dioxolane (DOL) in situ makes this approach very attractive. In this paper, we present the in situ electro-initiated polymerization of DOL in polyacrylonitrile nanofibrous mats, without using initiator or crosslinking agents. The amount of monomer loaded in the porous scaffold, the electrochemical technique used to initiate the polymerization and the salt amount were investigated as important parameters that affect the ion conductivity and the performance of the obtained polymer electrolyte. Particular attention was directed towards minimizing the presence of residual monomer in the resulting polymer, with the aim of progressing towards the development of a real solid-state polymer electrolyte. The results of the thermal, morphological, and electrochemical characterization are reported and discussed.

Lithium-ion batteries with silicon-graphite composite anodes feature an asymmetric and direction-dependent voltage hysteresis. Upon comparing established hysteresis models from literature, it was found that a separate modelling of charge and discharge direction is required for both the operator-based Preisach model and the differential equation-based one-state model, often referred to as Plett model. This paper presents the first bidirectional implementation of the one-state hysteresis model based on extensive measurements of first-order reversal branches of a Si/C NMC cell. The approach accounts for directionality but cannot deal with the complexity of the hysteresis traverses, so an extension of the Preisach model is discussed and found to be infeasible. This justifies the development of a novel hysteresis model, the trajectory correction hysteresis (TCH) model, that fulfils the identified requirements for bidirectionality, closed-loop property and direct data fit and can be generally applied to any cell chemistry. The TCH model considers the traverse starting point, which allows for the unambiguous definition of hysteresis states and enables the simulation of complex trajectories due to two correction mechanisms. The static and dynamic current profiles in complex hysteresis scenarios demonstrate superior performance with 4.5 mV mae compared to Preisach (19.6 mV mae) and Plett (11.7 mV mae) models.

Li-ion batteries (LIBs), thanks to high efficiencies and energy density, represent the mainstream technology to replace traditional internal combustion vehicles with electric ones. However, LIBs state of health (SoH) should be investigated to avoid fast degradation due to fast-charging, electrical, mechanical and thermal factors. Therefore, SoH prediction and monitoring for battery electric vehicles is necessary for extending LIB lifespan and avoiding failures. In this paper, an accurate real-time SoH prediction and monitoring method, based on discrete wavelet (DWT) analysis, is investigated through an extensive experimental campaign considering the effect of temperature variation. Specifically, moving from cycle aging performed on Li-ion NCR 18650 cells and applying two typical US test drive cycles at different SoHs, three different operating temperatures (i.e., 0 °C, 20 °C and 30 °C) were investigated. Applying DWT on the gathered LIB voltage profiles, it is demonstrated that temperature effect on the implemented method is easily recognizable from the one of cycle aging. Moreover, suitable linearized functions are identified to refer DWT outcomes assessed at the operative temperature to a reference temperature, at which a suitable equation is previously identified to assess capacity fading. Due to its general validity the method can be extended to stationary applications.

We demonstrate, as proof of concept, a materials design path that allows us to exploit thermal deposition technique to fabricate sodium (Na) metal anodes at the microscale. Our study reveals that Na thin anodes <10 μm, directly coated on a stainless-steel current collector, reduces the energy barrier of Na nucleation during plating process. Likewise, evaporated thin-film sodium anodes enable achieving a cycling in a full battery configuration as stable as with bulk Na anode, and considerably more stable than the here presented anode-less case. These insights may lead to practical design changes toward the efficient use of metallic Na, alleviating weight and costs. In addition, they provide a solid starting point for future developments that focus on improving the stability and extending the life of Na-metal batteries. All this paves the way for the next-generation of sodium-based energy storage technologies, where energy density and cost are key factors.

In this study, we propose an effective strategy to improve the electrochemical performance of a P2-Na_0.67Mn_0.75Ni_0.25O₂ (P2-MNO) cathode material for Na-ion batteries based on MgO surface coating. The MgO coating, with a thickness of ∼20–50 nm, is obtained by means of a facile wet-chemistry approach followed by heat treatment carried out at comparatively low temperatures (400–500 °C) in order to avoid possible Mg doping in the bulk of the P2-MNO. Detailed electrochemical investigations demonstrate improved electrochemical performance of the MgO-coated material (M-P2-MNO) in comparison to pristine bare one at both room and elevated (40 °C) temperatures. Operando differential electrochemical mass spectroscopy (DEMS) demonstrate that the MgO coating is effective in suppressing unwanted gas evolution due to side reactions thus stabilizing the cathode/electrolyte interface.

A novel approach to develop a low-temperature lithium-ion battery (LIB) based on tin selenide (SnSe) and carbon (C) nanofibers as the active electrode material has been successfully achieved. The SnSe@C nanofiber anode exhibited excellent electrochemical properties, such as high capacity and good rate capability. The anode maintained a consistent charge capacity of ∼923 mAh g⁻¹ at a current rate of 0.1 A g⁻¹ over 100 cycles at room temperature. Furthermore, investigated for the first time at low temperatures, the SnSe@C nanofiber anode exhibited superior capacity (∼430 mAh g⁻¹ at −20 °C) compared to conventional graphite electrode (∼25 mAh g⁻¹ at −20 °C). The proposed SnSe@C nanofiber anode demonstrated a great potential to be applied for developing next-generation LIBs with improved low-temperature performance.

This study investigates the impact of water ratio on the direct aqueous recycling of NMC811. Three different ratios of NMC811 to water were examined. The results demonstrate that the water ratio significantly affects the electrochemical performance of NMC811. Capacity fading is observed in all water-exposed samples, with the sample having the lowest water ratio showing less fading compared to the samples processed with higher water ratios. Both samples with higher water ratios exhibit similar performance, suggesting an equilibrium at the NMC811-water interface is established. Characterization of the cathode materials reveals variations in the amount and type of surface species. The pristine sample, not exposed to water, only shows Li₂CO₃ and NiO as surface species, while the water-exposed NMC811 samples exhibit nickel carbonates and hydroxides along with associated water. The poorer performance of samples exposed to higher water ratios is likely due to higher amounts of these species forming on the particle surface. Additionally, lithium, cobalt, and manganese carbonates, as well as lithium hydroxide with associated water, are detected and could further contribute to the poorer performance.

Li-ion capacitors (LICs) have emerged as promising energy storage devices within the electronic industry. The performance of LICs is predominantly influenced by the electrode material utilized, making the proper selection and development of said material of utmost importance. This study focuses on fabricating a composite electrode material using a simple, cost-effective, and environmentally friendly technique, combining Manganese dioxide (MnO₂) nanotube and graphene oxide (GO). The low cost, high natural abundance, and high theoretical specific capacity (1230 mAh/g) of MnO2 enables it to be effectively used in energy storage systems. The resulting material showcases a distinctive architecture where MnO₂ nanotube nanorods are enveloped by GO nanosheets. By employing a binder-free buckypaper approach, the MnO₂ nanotube/GO composite anode exhibits exceptional electrochemical performance, including high energy (213.29 Wh/kg) and power density (28.5 kW/kg), improved rate capability, and excellent cyclic stability. These findings undoubtedly indicate a promising future for the MnO₂ nanotube/GO composite anode in lithium-ion-based energy storage systems.

The Proton Exchange Membrane Fuel Cell (PEMFC), known for its efficient energy conversion, minimal electrolyte leakage, and low operating temperature, shows great potential as a clean energy source. However, its lifespan is limited due to degradation during normal operation, which, if uncontrolled, can result in dangerous failures such as explosions. Hence, accurately estimating the remaining useful life (RUL) is vital. In this research, a combined prediction method using genetic algorithms (GA) and nonlinear autoregressive neural networks (NARX) with external inputs is proposed. The method's performance was trained and validated using the 2014 IEEE PHM Data Challenge dataset, and it was compared to two commonly used artificial neural network algorithms: GA-based backpropagation neural network (GA-BPNN) and GA-based time delay neural network (GA-TDNN). The findings demonstrate that the proposed approach surpasses the other two artificial neural network algorithms in terms of prediction accuracy. Although GA is known for its computational requirement, optimization is performed offline. Once optimal neural network (NN) hyper-parameters are determined, the optimized NN is used online for RUL prediction.

Non-aqueous Li–O₂ batteries offer an extremely high energy density, but suffer from high overvoltage on charge and poor cycle characteristics. In the past decade, soluble redox mediators (RMs) have been utilized to reduce the charge overvoltage. However, the use of RMs inhibits the effective decomposition of Li₂O₂ due to the shuttling of RMs between the cathode and anode. In this study, 2,2,6,6-tetramethylpiperidinyloxyl (TEMPO), which was previously proposed as an RM, was immobilized on the electrode surface by immersing carbon paper in a solution of the synthesized 4-(N-(3-triethoxysilyl-propyl) carbamoyloxy)-2,2,6,6-tetramethyl-1-piperidinoxyl (TESPCP), followed by a heat treatment. Charge–discharge testing of Li–O₂ batteries using the TEMPO-immobilized cathode with a Li anode exhibited a charge plateau of about 3.7 V, indicating that the immobilized TEMPO could react electrochemically as a redox mediator. No overcharge behavior was observed in the cell, suggesting the RM shuttling effect was suppressed. Furthermore, SEM and XPS analyses of the cathode surface confirmed that no Li₂O₂ residues remained on the cathode after charging, unlike the control sample that utilized soluble RMs. These results indicate that a TEMPO-immobilized cathode can successfully mitigate RM shuttling while maintaining the benefits of RMs, allowing effective decomposition of Li₂O₂, during charging without leading to overcharging.