Search Results (19)

Efficient thermal management is critical for the performance, safety, and longevity of lithium-ion batteries, particularly in new energy vehicles. This paper presents the development and application of a NiCr/NiSi thin-film thermocouple fabricated via magnetron sputtering on a polyimide substrate, aiming to provide high-precision, fast-response internal temperature measurements for lithium-ion battery systems. The thermocouple demonstrates a Seebeck coefficient of approximately 40.95 μV/°C and a repeatability error of only 0.45%, making it highly suitable for capturing transient thermal events. The main innovation of this work lies in the comprehensive integration of simulation and experimental validation to optimize the thermocouple’s performance for lithium-ion battery applications. This includes static calibration, external short-circuit, and puncture tests, which collectively confirm the thermocouple’s reliability and accuracy. Additionally, the study explores the impact of ambient temperature variations on internal battery temperatures, revealing a nearly linear increase in internal temperature with rising ambient conditions. The findings offer valuable insights for improving battery thermal management systems, establishing early warning thresholds for thermal runaway, and enhancing the overall safety of lithium-ion battery applications. Full article

In this study, the effects of specific power (1–100 W/cm²), operating pressure (0.5–3.0 Pa), and voltage frequency (20–500 kHz) on film growth kinetics, morphology, and silicon entrainment were investigated to optimize magnetron sputtering for producing thin silicon films suitable for lithium-ion battery anodes. Silicon films were deposited on copper substrates using the Caroline D12C system. The film thickness and morphology were determined using scanning electron microscopy and atomic force microscopy. It was found that the porosity of the films increases with increasing pressure in the working chamber. It was found that the film morphology is non-uniform up to a thickness of 100–150 nm. After that, the film thickness becomes uniform over the entire substrate surface, and the deposition rate increases sharply, i.e., an induction period is observed. The induction period duration decreases with increasing voltage power and frequency. At the same time, silicon removal increases. Frequency has a greater effect on both parameters. The paper specifies a strategy for the technical and economic optimization of the magnetron sputtering process, which determines a compromise between the positive effect of increasing productivity and the negative effect of silicon removal. Full article

Despite their high specific capacity, magnetron-sputtered Si/Al thin films face rapid capacity decay due to stress-induced cracking, delamination, and detrimental electrolyte reactions. This study introduces a carbon-coated composite anode that overcomes these limitations, delivering superior reversible capacity, exceptional rate capability, and stable cycling performance. An electrochemical evaluation reveals that the CF-Si/Al@C-500-1h composite exhibits marked enhancements in capacity retention (43.5% after 100 cycles at 0.6 A·g⁻¹) and rate capability, maintaining 579.1 mAh·g⁻¹ at 3 A·g⁻¹ (1 C). The carbon layer enhances electrical conductivity, buffers volume expansion during lithiation/delithiation, and suppresses silicon aggregation and electrolyte side reactions. Coupled with an aluminum framework, this architecture ensures robust structural integrity and efficient lithium-ion transport. These advancements position CF-Si/Al@C-500-1h as a promising anode material for next-generation lithium-ion batteries, while insights into scalable fabrication and carbon integration strategies pave the way for practical applications. Full article

This study investigates the properties of LiCoO₂ coatings as cathodes for lithium-ion batteries, focusing on the effects of annealing on their structural, morphological, chemical, vibrational, and electrochemical characteristics. The LiCoO₂ coatings were deposited on silicon and glass substrates using RF magnetron sputtering at 100 W and subsequently annealed at 600 °C for 1 h. The films were characterized before and after annealing using X-ray diffraction (XRD), scanning electron microscopy (SEM), energy-dispersive spectroscopy (EDS), X-ray photoelectron spectroscopy (XPS), Raman spectroscopy, and electrochemical impedance spectroscopy (EIS). Annealing improved the crystallinity of LiCoO₂, which is critical for enhancing lithium-ion diffusion. Furthermore, an XPS analysis revealed a layered structure with a Li-rich outer layer and a Co-rich underlayer, indicating a more uniform distribution of Li and Co, along with increased oxygen content. Additionally, the annealing process refined the microstructure of the LiCoO₂ coating, positively impacting its electrochemical performance. A comparative analysis of cyclic voltammetry (CV) and galvanostatic charge/discharge (GCD) results demonstrated a significant improvement in the charge/discharge capacity post-annealing. This study successfully highlights the beneficial effects of annealing on LiCoO₂ thin-film cathodes, offering valuable insights for developing more efficient and sustainable lithium-ion batteries through sputter-deposition processes. Full article

Silicon (Si) as the anode material for lithium-ion batteries (LIBs) has attracted much attention due to its high theoretical specific capacity (4200 mAh/g). However, the specific capacity and cycle stability of the LIBs are reduced due to the pulverization caused by the expansion of Si coated on Cu (copper) foil during cycles. In order to solve this problem, researchers have used an ultra-thin Si deposition layer as the electrode, which improves cyclic stability and obtains high initial coulomb efficiency of LIBs. However, suitable substrate selection is crucial to fabricate an ultrathin Si deposition layer electrode with excellent performance, and a substrate with a three-dimensional porous structure is desirable to ensure the deposition of an ultrathin Si layer on the whole surface of the substrate. In this paper, the Si thin layer has been deposited on a binder-free hybrid film of carbon nanotubes (CNTs) and carbon nanocoils (CNCs) by magnetron sputtering. Compared with densely packed CNT film and flat Cu foil, the loose and porous film provides a large surface area and space for Si deposition, and Si can be deposited not only on the surface but also in the interior part of the film. The film provides a large number of channels for the diffusion and transmission of Li⁺, resulting in the rapid diffusion rate of Li⁺, which improves the effective lithium storage utilization of Si. Furthermore, the CNC itself is super elastic, and film provides an elastic skeleton for the Si deposition layer, which eases its volume expansion during charge and discharge processes. Electrochemical tests have showed that the Si/CNT–CNC film electrode has excellent performance as anode for LIBs. After 200 cycles, the Si/CNT–CNC film electrode still had possessed a specific capacity of 2500 mAh/g, a capacity retention of 92.8% and a coulomb efficiency of 99%. This paper provides an effective way to fabricate high performance Si-nanocarbon composite electrodes for LIBs. Full article

Thin copper and carbon coatings of electrodes of lithium-ion batteries (LIBs) have the potential to improve LIB operation by preserving electrode integrity during cycling, by developing a proper solid-electrolyte interphase (SEI) layer (e.g., by increasing the de-solvation rate), and by enhancing electric conductivity. In the structures, the thin coatings, e.g., copper thin films, must be permeable to Li⁺ ions in order to facilitate Li⁺ uptake and Li⁺ release in the electrochemically active material of coated electrodes beneath. The influences of copper and carbon thin coatings on LIB-electrode performance were investigated in this work by electrochemically cycling a [C(16 nm)/Cu(17 nm)] × 10 multilayer (ML) up to lithium plating. The C/Cu ML was deposited onto a copper current collector using ion beam sputtering. The rate capability and the long-time cycling were compared to the corresponding ones for the cycling of the bare copper substrate and 16 nm and 230 nm carbon single films (without Cu coating). The bare copper electrode does not store Li⁺ ions, which is as expected because copper is electrochemically inactive with respect to lithiation. The Li⁺ uptake and Li⁺ release in thin carbon layers capped by thin copper layers within the C/Cu ML is compared to that of uncapped carbon single thin films. All electrodes exhibited a good rate capability and long-term cycling stability. Under fast cycling, the amount of reversible Li⁺ uptake and Li⁺ release was largest for the case of the C/Cu ML, which pointed to the beneficial influence of the capping Cu layers. The higher Li kinetics in the C/Cu ML was confirmed using impedance analysis. The C/Cu ML behaves as a supercapacitor possessing a differential charge plot nearly independent of potential. At lower currents, the specific capacity of the C/Cu ML is only 20% of that of the thin carbon single films, with that of the latter being the same as that of graphite. On the one hand, this evidences a disadvantageous influence of the thin Cu layers, which block the Li⁺ permeation, that is necessary to reach deeper carbon layers of the C/Cu ML electrode. On the other hand, the differential capacity plots reveal that the carbon material in the interior of the C/Cu ML is electrochemically cycled. Microscopy, Raman scattering, depth profiling with X-ray reflectometry (XRR), and secondary ion mass spectrometry (SIMS) were applied to get deep insights and a comprehensive examination of the contradiction. The XRR examination revealed a non-altered ML after more than 542 electrochemical cycles, after the washing procedure, and even after 15 months of air exposure. This observation suggests that the copper layers block contamination as well as the Li insertion. The analyses of microscopy, Raman, and SIMS affirm the ML intactness but also reveal the participation of some portions of the interior of the C/Cu ML in electrochemical cycling. The low capacity of carbon in the C/Cu ML may stem from the mechanical stress inside the C/Cu ML, which reduces the Li⁺ uptake and Li⁺ release. Full article

In this study we present gas-phase fluorination as a method to create a thin LiF layer on Li_6.5La₃Zr_1.5Ta_0.5O₁₂ (LLZTO). We compared these fluorinated films with LiF films produced by RF-magnetron sputtering, where we investigated the interface between the LLZTO and the deposited LiF showing no formation of a reaction layer. Furthermore, we investigated the ability of this LiF layer as a protection layer against Li₂CO₃ formation in ambient air. By this, we show that Li₂CO₃ formation is absent at the LLZTO surface after 24 h in ambient air, supporting the protective character of the formed LiF films, and hence potentially enhancing the handling of LLZTO in air for battery production. With respect to the use within hybrid electrolytes consisting of LLZTO and a mixture of polyethylene oxide (PEO) and lithium bis(trifluoromethanesulfonyl)imide (LiTFSI), we also investigated the interface between the formed LiF films and a mixture of PEO+LiTFSI by X-ray photoelectron spectroscopy (XPS), showing decomposition of the LiTFSI at the interface. Full article

High Power Impulse Magnetron Sputtering (HiPIMS) has generated a great deal of interest by offering significant advantages such as high target ionization rate, high plasma density, and the smooth surface of the sputtered films. This study discusses the deposition of copper nitride thin films via HiPIMS at different deposition pressures and then examines the impact of the deposition pressure on the structural and electrical properties of Cu₃N films. At low deposition pressure, Cu-rich Cu₃N films were obtained, which results in the n-type semiconductor behavior of the films. When the deposition pressure is increased to above 15 mtorr, Cu₃N phase forms, leading to a change in the conductivity type of the film from n-type to p-type. According to our analysis, the Cu₃N film deposited at 15 mtorr shows p-type conduction with the lowest resistivity of 0.024 Ω·cm and the highest carrier concentration of 1.43 × 10²⁰ cm⁻³. Furthermore, compared to the properties of Cu₃N films deposited via conventional direct current magnetron sputtering (DCMS), the films deposited via HiPIMS show better conductivity due to the higher ionization rate of HiPIMS. These results enhance the potential of Cu₃N films’ use in smart futuristic devices such as photodetection, photovoltaic absorbers, lithium-ion batteries, etc. Full article

In this work, a comprehensive investigation of amorphous and crystalline modification of identical electrode active material as a thin-film electrode for a future all-solid-state Li-ion battery application is presented and discussed. Using the proposed micro-battery system, we aim to unravel the effect of the crystallinity of the positive electrode material on the intrinsic durability of all-solid-state thin-film Li-ion batteries during prolonged electrochemical cycling. We demonstrate the preparation, structural-, nanomechanical and electrochemical characteristics of molybdenum (VI) oxide (MoO₃) thin-film cathodes based on their different crystallinity. The nanomechanical properties of the electrode layers were determined using nanoindentation along with acoustic emission studies. Based on the electrochemical test results, as-prepared thin films that did not go under any heat treatment showed the best performance and stability throughout cycling around 50 μAh initial capacity when cycled at C/2. This suits well their nanomechanical properties, which showed the highest hardness but also the highest flexibility in comparison with the heat-treated layers with lower hardness, high brittleness, and numerous cracks upon mechanical loads. According to our results, we state that amorphous-type electrode materials are more durable against electro-chemo-mechanical-aging related battery performance loss in all-solid-state Li-ion batteries compared to their crystalline counterparts. Full article

The microbatteries field is an important direction of energy storage systems, requiring the careful miniaturization of existing materials while maintaining their properties. Over recent decades, LiCoO₂ has attracted considerable attention as cathode materials for lithium-ion batteries due to its promising electrochemical properties for high-performance batteries. In this work, the thin films of LiCoO₂ were obtained by radio-frequency magnetron sputtering of the corresponding target. In order to obtain the desired crystal structure, the parameters such as annealing time, temperature, and heating rate were varied and found to influence the rhombohedral phase formation. The electrochemical performances of the prepared thin films were examined as a function of annealing time, temperature, and heating rate. The LiCoO₂ thin film cathode annealed at 550 °C for 1 h 20 min demonstrated the best cycling performance with a discharge specific capacity of around 135 mAh g⁻¹ and volumetric capacity of 50 µAh cm⁻²µm⁻¹ with a 77% retention at 0.5 C rate. Full article

Along with the soaring demands for all-solid-state thin-film lithium-ion batteries, the problem of their energy density rise becomes very acute. The solution to this problem can be found in development of 3D batteries. The present work deals with the development of a technology for a 3D solid-state lithium-ion battery (3D SSLIB) manufacturing by plasma-chemical etching and magnetron sputtering technique. The results on testing of experimental samples of 3D SSLIB are presented. It was found that submicron-scale steps appearing on the surface of a 3D structure formed on Si substrate by the Bosch process radically change the crystal structure of the upper functional layers. Such changes can lead to disruption of the layers’ continuity, especially that of the down conductors. It is shown that surface polishing by liquid etching of the SiO₂ layer and silicon reoxidation leads to surface smoothing, the replacement of the dendrite structure of functional layers by a block structure, and a significant improvement in the capacitive characteristics of the battery. Full article

Silicon and silicon nitride (Si₃N₄) are some of the most appealing candidates as anode materials for LIBs (Li-ion battery) due to their favorable characteristics: low cost, abundance of Si, and high theoretical capacity. However, these materials have their own set of challenges that need to be addressed for practical applications. A thin film consisting of silicon nitride-coated silicon on a copper current collector (Si₃N₄@Si@Cu) has been prepared in this work via RF magnetron sputtering (Radio Frequency magnetron sputtering). The anode material was characterized before and after cycling to assess the difference in appearance and composition using XRD (X-ray Powder Diffraction), XPS (X-ray Photoelectron Spectroscopy), SEM/EDX (Scanning Electron Microscopy/ Energy Dispersive X-Ray Analysis), and TEM (Transmission Electron Microscopy). The effect of the silicon nitride coating on the electrochemical performance of the anode material for LIBs was evaluated against Si@Cu film. It has been found that the Si₃N₄@Si@Cu anode achieved a higher capacity retention (90%) compared to Si@Cu (20%) after 50 cycles in a half-cell versus Li⁺/Li, indicating a significant improvement in electrochemical performance. In a full cell, the Si₃N₄@Si@Cu anode achieved excellent efficiency and acceptable specific capacities, which can be enhanced with further research. Full article

Cu@Si core–shell nanowire thin films with a Cu₃Si interface between the Cu and Si were synthesized by slurry casting and subsequent magnetron sputtering and investigated as anode materials for lithium ion batteries. In this constructed core–shell architecture, the Cu nanowires were connected to each other or to the Cu foil, forming a three-dimensional electron-conductive network and as mechanical support for the Si during cycling. Meanwhile, the Cu₃Si layer can enhance the interface adhesion strength of the Cu core and Si shell; a large amount of void spaces between the Cu@Si nanowires could accommodate the lithiation-induced volume expansion and facilitate electrolyte impregnation. As a consequence, this electrode exhibits impressive electrochemical properties: the initial discharge capacity and initial coulombic efficiency is 3193 mAh/g and 87%, respectively. After 500 cycles, the discharge capacity is about 948 mAh/g, three times that of graphite, corresponding to an average capacity fading rate of 0.2% per cycle. Full article

Recently, applications for lithium-ion batteries (LIBs) have expanded to include electric vehicles and electric energy storage systems, extending beyond power sources for portable electronic devices. The power sources of these flexible electronic devices require the creation of thin, light, and flexible power supply devices such as flexile electrolytes/insulators, electrode materials, current collectors, and batteries that play an important role in packaging. Demand will require the progress of modern electrode materials with high capacity, rate capability, cycle stability, electrical conductivity, and mechanical flexibility for the time to come. The integration of high electrical conductivity and flexible buckypaper (oxidized Multi-walled carbon nanotubes (MWCNTs) film) and high theoretical capacity silicon materials are effective for obtaining superior high-energy-density and flexible electrode materials. Therefore, this study focuses on improving the high-capacity, capability-cycling stability of the thin-film Si buckypaper free-standing electrodes for lightweight and flexible energy-supply devices. First, buckypaper (oxidized MWCNTs) was prepared by assembling a free stand-alone electrode, and electrical conductivity tests confirmed that the buckypaper has sufficient electrical conductivity (10⁻⁴(S m⁻¹) in LIBs) to operate simultaneously with a current collector. Subsequently, silicon was deposited on the buckypaper via magnetron sputtering. Next, the thin-film Si buckypaper freestanding electrodes were heat-treated at 600 °C in a vacuum, which improved their electrochemical performance significantly. Electrochemical results demonstrated that the electrode capacity can be increased by 27/26 and 95/93 μAh in unheated and heated buckypaper current collectors, respectively. The measured discharge/charge capacities of the USi_HBP electrode were 108/106 μAh after 100 cycles, corresponding to a Coulombic efficiency of 98.1%, whereas the HSi_HBP electrode indicated a discharge/charge capacity of 193/192 μAh at the 100th cycle, corresponding to a capacity retention of 99.5%. In particular, the HSi_HBP electrode can decrease the capacity by less than 1.5% compared with the value of the first cycle after 100 cycles, demonstrating excellent electrochemical stability. Full article

Due to the abundance and low cost of exchanged metal, sodium-ion batteries have attracted increasing research attention for the massive energy storage associated with renewable energy sources. Nickel oxide (NiO) thin films have been prepared by magnetron sputtering (MS) deposition under an oblique angle configuration (OAD) and used as electrodes for Na-ion batteries. A systematic chemical, structural and electrochemical analysis of this electrode has been carried out. The electrochemical characterization by galvanostatic charge–discharge cycling and cyclic voltammetry has revealed a certain loss of performance after the initial cycling of the battery. The conversion reaction of NiO with sodium ions during the discharge process to generate sodium oxide and Ni metal has been confirmed by X-ray photoelectron spectra (XPS) and micro-Raman analysis. Likewise, it has been determined that the charging process is not totally reversible, causing a reduction in battery capacity. Full article