Search Results (1,088)

Given the increasing use of lithium-ion batteries, which is driven in particular by electromobility, the characterization of cells in production and application plays a decisive role in quality assurance. The detection of defects particularly motivates the optimization and development of innovative characterization methods, with simultaneous testing of multiple cells in the context of multi-cell setups having been researched to economize on the number of cell test channels required. In this work, an experimental study is presented demonstrating the influence of a defect type in one cell on five remaining interconnected cells in eight combinatorially varied topologies using galvanostatic electrochemical impedance spectroscopy. The results show that regularities related to the interconnection position are revealed when considering the change in the specific resistance $Z_{IM,min}$ at the transition from the charge transfer to the diffusion region between the reference and fault measurements, allowing it to function as a defect identifier in the present scenario. These results and the extensive measurement data provided can serve as a basis for the evaluation and design of multi-cell setups used for simultaneous impedance-based lithium-ion cell characterizations. Full article

The state of health (SOH) evaluation and remaining useful life (RUL) prediction for lithium-ion batteries (LIBs) are crucial for health management. This paper proposes a novel sequence-to-sequence (Seq2Seq) prediction method for LIB capacity degradation based on the gated recurrent unit (GRU) neural network with the attention mechanism. An improved particle swarm optimization (IPSO) algorithm is developed for automatic hyperparameter search of the Seq2Seq model, which speeds up parameter convergence and avoids getting stuck in local optima. Before model training, the complete ensemble empirical mode decomposition with adaptive noise (CEEMDAN) algorithm decomposes the capacity degradation sequences. And the intrinsic mode function (IMF) components with the highest correlation are employed to reconstruct the sequences, reducing the influence of noise in the original data. A real-cycle-life data set under fixed operating conditions is employed to validate the superiority and effectiveness of the method. The comparison results demonstrate that the proposed model outperforms traditional GRU and RNN models. The predicted mean absolute percent error (MAPE) in SOH evaluation and RUL prediction can be as low as 0.76% and 0.24%, respectively. Full article

Battery degradation is a complex nonlinear problem, and it is crucial to accurately predict the cycle life of lithium-ion batteries to optimize the usage of battery systems. However, diverse chemistries, designs, and degradation mechanisms, as well as dynamic cycle conditions, have remained significant challenges. We created 53 features from discharge voltage curves, 18 of which were newly developed. The maximum relevance minimum redundancy (MRMR) algorithm was used for feature selection. Robust linear regression (RLR) and Gaussian process regression (GPR) algorithms were deployed on three different datasets to estimate battery cycle life. The RLR and GPR algorithms achieved high performance, with a root-mean-square error of 6.90% and 6.33% in the worst case, respectively. This work highlights the potential of combining feature engineering and machine learning modeling based only on discharge voltage curves to estimate battery degradation and could be applied to onboard applications that require efficient estimation of battery cycle life in real time. Full article

In this paper, we investigate different current collector materials for in situ deposition of lithium using a slurry-based $\mathsf{\beta }$-Li₃PS₄ electrolyte layer with a focus on transferability to industrial production. Therefore, half-cells with different current collector materials (carbon-coated aluminum, stainless steel, aluminum, nickel) are prepared and plating/stripping tests are performed. The results are compared in terms of Coulombic efficiency (CE) and overvoltages. The stainless steel current collector shows the best performance, with a mean efficiency of ${\mathsf{\eta }}_{\mathrm{mean},\mathrm{SST}}=98\%$; the carbon-coated aluminum reaches ${\mathsf{\eta }}_{\mathrm{mean},\mathrm{Al}+\mathrm{C}}=97\%$. The results for pure aluminum and nickel indicate strong side reactions. In addition, an approach is tested in which a solvate ionic liquid (SIL) is added to the solid electrolyte layer. Compared to the cell setup without SIL, this cannot further increase the CE; however, a significant reduction in overvoltages is achieved. Full article

The wide application of lithium-ion batteries (LIBs) brings along with it various safety problems, such as fire and explosion accidents. Aiming at the thermal runaway (TR) and fire problems of LIBs, we reviewed the evolution of TR within LIB and the release of TR gases and their hazards, as well as the research progress in recent years in the area of fire separation of LIBs. To begin with, physical, electrical, and thermal abuse are the three main factors leading to TR and the thermal stability of aging batteries significantly deteriorates. Furthermore, the decomposition of the electrolyte and the reaction between the active materials generates CO, CO₂, H₂, HF, and a variety of hydrocarbons. These TR gases have serious toxic and explosive hazards. In addition, fire separation can effectively delay the occurrence and propagation of TR within LIB modules. As a good heat-absorbing material, phase-change materials are widely used in the thermal management system and have a great prospect of wide applications in the fire separation of LIBs. Finally, the research on the TR gases’ hazards of aging LIB and safer and more effective fire separation are prospected. Full article

Because the new energy is intermittent and uncertain, it has an influence on the system’s output power stability. A hydrogen energy storage system is added to the system to create a wind, light, and hydrogen integrated energy system, which increases the utilization rate of renewable energy while encouraging the consumption of renewable energy and lowering the rate of abandoning wind and light. Considering the system’s comprehensive operation cost economy, power fluctuation, and power shortage as the goal, considering the relationship between power generation and load, assigning charging and discharging commands to storage batteries and hydrogen energy storage, and constructing a model for optimal capacity allocation of wind–hydrogen microgrid system. The optimal configuration model of the wind, solar, and hydrogen microgrid system capacity is constructed. A particle swarm optimization with dynamic adjustment of inertial weight (IDW-PSO) is proposed to solve the optimal allocation scheme of the model in order to achieve the optimal allocation of energy storage capacity in a wind–hydrogen storage microgrid. Finally, a microgrid system in Beijing is taken as an example for simulation and solution, and the results demonstrate that the proposed approach has the characteristics to optimize the economy and improve the capacity of renewable energy consumption, realize the inhibition of the fluctuations of power, reduce system power shortage, and accelerate the convergence speed. Full article

Redox flow batteries represent a captivating class of electrochemical energy systems that are gaining prominence in large-scale storage applications. These batteries offer remarkable scalability, flexible operation, extended cycling life, and moderate maintenance costs. The fundamental operation and structure of these batteries revolve around the flow of an electrolyte, which facilitates energy conversion and storage. Notably, the power and energy capacities can be independently designed, allowing for the conversion of chemical energy from input fuel into electricity at working electrodes, resembling the functioning of fuel cells. This work provides a comprehensive overview of the components, advantages, disadvantages, and challenges of redox flow batteries (RFBs). Moreover, it explores various diagnostic techniques employed in analyzing flow batteries. The discussion encompasses the utilization of RFBs for large-scale energy storage applications and summarizes the engineering design aspects related to these batteries. Additionally, this study delves into emerging technologies, applications, and challenges in the realm of redox flow batteries. Full article

Anode-less sodium metal batteries have drawn dramatica attention owing to their high specific energy and low cost. However, the growth of sodium dendrites and the resulting loss of active materials and serious safety concerns hinder their practical applications. In this work, a bismuth-based modification layer with good sodiophilicity is constructed on the surface of Cu foil (denoted as [email protected]) to control the deposition of Na metal. The activation-derived porous Na-rich alloy phase can provide abundant nucleation sites and reduce the nucleation overpotential to induce the uniform and dense deposition of Na metal. When evaluated in half cell, the [email protected] current collectors can operate for 750 h at 1 mA cm⁻² and 1 mAh cm⁻², with an average coulombic efficiency (CE) of 99.5%. When the current density is improved to 2 mA cm⁻², the [email protected] can also stably maintain for 750 cycles, demonstrating the remarkable effect of the modification layer. When coupled with the Na₃V₂(PO₄)₃ cathode, the full cell exhibits stable cycle performance over 80 cycles. The modification strategy of alloy modification can provide fresh ideas for the research and application of anode-less and even anode-free metal batteries. Full article

All-solid-state lithium batteries are a promising alternative to commercially available lithium-ion batteries due to their ability to achieve high energy density, safety, and compactness. Electrolytes are key components of all-solid-state batteries, as they are crucial in determining the batteries’ efficiency. Herein, the structure of LiM₂(PO₄)₃ (M = Ti, Ge, Zr) and lithium-ion migration mechanisms are introduced as well as different synthetic routes and doping (co-doping), and their influence on conductivity is discussed. The effective methods of reducing electrolyte/electrode interface resistance and improving ion-conducting properties are summarized. In addition, different polymer/NASICON composites are considered. The challenges and prospects of practical applications of NASICON-type lithium phosphates as electrolytes for all-solid-state batteries are discussed. Full article

This study presents a thorough investigation of Na₂FeP₂O₇ (NFP) cathode material for sodium-ion batteries and its composites with carbon and reduced graphene oxide (rGO). Our findings demonstrate that rGO sheets improve cycling performance in NFP/C/rGO composite in the absence of solid electrolyte interphase (SEI)-stabilizing additives. However, once SEI is stabilized with the help of fluoroethylene carbonate electrolyte additive, NFP with carbon additive (NFP/C) exhibits a superior electrochemical performance when compared to NFP/rGO and NFP/C/rGO composites. The decreases in capacity and rate capability are proportional to the amount of rGO added, and lead to an increase in overvoltage and internal resistance. Based on our results, we attribute this effect to worsened sodium kinetics in the bulk of the electrode—the larger ionic radius of Na⁺ hinders charge transfer in the presence of rGO, despite the likely improved electronic conductivity. These findings provide a compelling explanation for the observed trends in electrochemical performance and suggest that the use of rGO in Na-ion battery electrodes may present challenges associated with ionic transport along and through rGO sheets. Full article

The advantages of low cost, high theoretical capacity, and dependable safety of aqueous zinc ion hybrid supercapacitors (ZHSCs) enable their promising use in flexible and wearable energy storage devices. However, achieving extended cycling stability in ZHSCs is still challenged by the limited availability of carbon cathode materials that can effectively pair with zinc anode materials. Here, we report a method for synthesising heteroatom-doped carbon nanofibers using electrostatic spinning and metal-organic frameworks (specifically ZIF-8). Assembled Zn//ZPCNF-1.5 ZHSCs exhibited 193 mA h g⁻¹ specific capacity at 1 A g⁻¹ and 162.6 Wh kg⁻¹ energy density at 841.2 kW kg⁻¹. Additionally, the device showed an ultra-long cycle life, maintaining 98% capacity after 20,000 cycles. Experimental analysis revealed an increase in the number of pores and active sites after adding ZIF-8 to the precursor. Furthermore, N doping effectively enhanced Zn²⁺ ions chemical adsorption and improved Zn-ion storage performance. This work provides a feasible design strategy to enhance ZHSC energy storage capability for practical applications. Full article

To gain better understanding of the safety behavior of lithium-ion batteries under mechanical stress, crush tests are performed and reported in literature and in standards. However, many of these tests are conducted without the use of a cell clamping device, whereas external pressure is applied to the cell in a battery module in applications such as in an electric vehicle. The objective of this manuscript is to determine the effect of differing external compression on the thermal runaway of battery cells. Therefore, in this study, crush tests are performed with a hemispherical punch in a battery cell test chamber on commercially available 5 Ah pouch cells in a clamping device at four different normal stresses. The results are compared to cells that are free to expand with gas evolution. It is shown that applying compression to the cells not only results in a greater reproducibility of the experiments but that it also affects the thermal runaway process itself. With decreasing clamping stresses, the reaction time of the thermal runaway is increased by up to 19%, and the mass ejection is decreased by up to 10%, which, in turn, strongly influences the measurable gas concentrations by up to 80%. Based on this, a defined clamping compression was selected to obtain comparable results for different cell formats. Full article

Ferroferric oxide (Fe₃O₄) is regarded to be a promising high-capacity anode material for LIBs. However, the capacity attenuates fast and the rate performance is poor due to the dramatic pulverization and sluggish charge transfer properties. To solve these problems, a simple in situ encapsulation and composite method was successfully developed to construct carbon nanotube/nanorod/nanosheet-supported Fe₃O₄ nanoparticles. Owing to the hierarchical architecture design, the novel structure Fe₃O₄@C nanocomposites effectively enhance the charge transfer, alleviate pulverization, avoid the agglomeration of Fe₃O₄ nanoparticles, and also provide superior kinetics toward lithium storage, thereby showing significantly improved reversibility and rate performance. The carbon nanotube/nanorod supported core-shell structure Fe₃O₄@C nanocomposite displays outstanding high rate capability and stable cycling performance (reversible capability of 1006, 552 and 423 mA h g⁻¹ at 0.2, 0.5 and 1 A g⁻¹ after running 100, 300 and 500 cycles, respectively). Full article

Anode-less batteries are a promising innovation in energy storage technology, eliminating the need for traditional anodes and offering potential improvements in efficiency and capacity. Here, we have fabricated and tested two types of anode-less pouch cells, the first using solely a copper negative current collector and the other the same current collector but coated with a nucleation seed ZnO layer. Both types of cells used the same all-solid-state electrolyte, Li_2.99Ba_0.005ClO composite, in a cellulose matrix and a LiFePO₄ cathode. Direct and indirect methods confirmed Li metal anode plating after charging the cells. The direct methods are X-ray photoelectron spectroscopy (XPS) and laser-induced breakdown spectroscopy (LIBS), a technique not divulged in the battery world but friendly to study the surface of the negative current collector, as it detects lithium. The indirect methods used were electrochemical cycling and impedance and scanning electron microscopy (SEM). It became evident the presence of plated Li on the surface of the current collector in contact with the electrolyte upon charging, both directly and indirectly. A maximum average lithium plating thickness of 2.9 µm was charged, and 0.13 µm was discharged. The discharge initiates from a maximum potential of 3.2 V, solely possible if an anode-like high chemical potential phase, such as Li, would form while plating. Although the ratings and energy densities are minor in this study, it was concluded that a layer of ZnO, even at 25 °C, allows for higher discharge power for more hours than plain Cu. It was observed that where Li plates on ZnO, Zn is not detected or barely detected by XPS. The present anode-less cells discharge quickly initially at higher potentials but may hold a discharge potential for many hours, likely due to the ferroelectric character of the electrolyte. Full article

Increasing demand to store intermittent renewable electricity from, e.g., photovoltaic and wind energy, has led to much research and development in large-scale stationary energy storage, for example, ZEBRA batteries (Na-NiCl₂ solid electrolyte batteries). Replacing Ni with abundant and low-cost Zn makes the ZEBRA battery more cost-effective. However, few studies were performed on this next-generation ZEBRA (Na-ZnCl₂) battery system, particularly on its AlCl₃-NaCl-ZnCl₂ secondary electrolyte. Its properties such as phase diagrams and vapor pressures are vital for the cell design and optimization. In our previous work, a simulation-assisted method for molten salt electrolyte selection has shown its successful application in development of molten salt batteries. The same method is used here to in-depth study the AlCl₃-NaCl-ZnCl₂ salt electrolyte in terms of its phase diagrams and vapor pressures via FactSage^TM and thermo-analytical techniques (Differential Scanning Calorimetry (DSC) and OptiMelt^TM), and their effects on battery performance such as operation safety and charging/discharging reaction mechanism. The DSC and OptiMelt results show that the experimental data such as melting temperatures and phase changes agree well with the simulated phase diagrams. Moreover, the FactSage^TM simulation shows that the salt vapor pressure increases significantly with increasing temperature and molar fraction of AlCl₃. The obtained phase diagrams and vapor pressures will be used in the secondary electrolyte selection, cell design and battery operation. Full article