Electrodes For Lithium-ion Batteries Research Articles

Investigating the Influence of Different Aprotic Processing Solvents for the PVdF Binder on the Microstructure and Electrochemical Performance of High-Load Positive Electrodes for Lithium Ion Batteries

Investigating the Influence of Different Aprotic Processing Solvents for the PVdF Binder on the Microstructure and Electrochemical Performance of High-Load Positive Electrodes for Lithium Ion Batteries

Effect of the Physicochemical Properties of PVdF on Dry-Sprayed Graphite Electrodes for Lithium-Ion Batteries for Electric Vehicle Applications

Abstract We investigated the fabrication of graphite/PVdF anodes using electrostatic dry spray-coating, employing two different PVdF binders with different physicochemical properties such as primary particle size, crystallinity, melting temperature, and viscosity. We examine and compare the morphological, mechanical, electrical, and electrochemical properties of the dry-sprayed electrodes (DSEs). Significant differences were observed, particularly in terms of adhesion/cohesion, electrical resistivity, tortuosity, and electrochemical performance, with the PVdF binder characterized by a smaller particle size (178 nm) and a slightly higher melting temperature range (165–172°C), demonstrating superior long-term cycling stability. Specifically, the best electrode made with this binder achieved 188.3 mAh g-1 with over 94.9% capacity retention after 200 cycles. In contrast, the best electrode made with the PVdF binder with a larger particle size (270 nm) and a lower melting temperature range (155–172°C), showed a performance of 173.9 mAh g-1 with 88.3% capacity retention under the same conditions. Our findings highlight the necessity of adjusting fabrication conditions according to the specific characteristics of each PVdF binder to optimize the overall performance of the DSEs.

High-Resolution X-ray Mapping of Fluorinated Binders in Lithium-Ion Battery Electrodes

High-Resolution X-ray Mapping of Fluorinated Binders in Lithium-Ion Battery Electrodes

Cu@MOF based composite materials: High performance anode electrodes for lithium-ion and sodium-ion batteries

In order to satisfy the increasing demand for energy, it is essential to improve the efficiency of lithium-ion batteries (LIBs) and sodium-ion batteries (SIBs) batteries. Metal selenides (MSes) have a high theoretical specific capacity, can be designed in a variety of ways, conduct electricity well, can change morphology easily, and have a multi-electron reaction mechanism. These characteristics make them very competitive as anode materials for LIBs and SIBs. Herein, we synthesise Cu@MOF and Cu@NH2-MOF as the precursor to prepare Cu1.95Se embedded into porous carbon matrix (Cu1.95Se@PC) and porous-N-doped carbon matrix (Cu1.95Se@NPC) via pyrolysis process of Cu@MOF and Cu@NH2-MOF, respectively. Cu1.95Se@PC and Cu1.95Se@NPC electrodes for half-cell LIBs and SIBs exhibit a high reversible capacity of 313.1, 480.9 (for LIBs), 216.3 and 303.8 (for SIBs) mAhg−1after 1000 cycles at 2 A g−1, respectively. We assess the electrochemical performance of the Cu1.95Se@PC and Cu1.95Se@NPC anodes by integrating them with commercially available LiFePO4 (LFP) into full-cell LIBs. The LFP//Cu1.95Se@PC and LFP//Cu1.95Se@NPC full-cells have discharge capacities of approximately 330 and 293 mAh g−1 at 0.3 A g−1 at the initial cycle. In order to explore the sodium storage mechanism of the Cu1.95Se composites, we conducted an in situ XRD test during the first charge/discharge cycle, considering their favourable cycling and rate performance. Our work provides a promising anode electrode material for both half-cell LIBs and SIBs with high volume utilization and superior electrochemical performances.

Designing 2D Janus Zr[formula omitted]CTX MXenes for anode materials in lithium-ion batteries

Background:Recently, 2D MXenes have shown great potential for use as electrode materials in lithium-ion batteries because of their unique layered structures and superior mechanical properties. Methods:Density functional theory (DFT) was utilized to explore the potential applications of 2D Janus Zr-based MXenes with various surface atoms, including O, S, Se, and Te, as anode materials in lithium-ion batteries. Significant Findings:The results showed that ▪ possesses excellent capacity and mechanical properties except for its non-metallic nature, limiting its application as the anode material. By selectively substituting O on one side of the ▪ surface by Se and Te, resulting in ▪ and ▪ , respectively, the materials exhibit metallic characteristics. Both ▪ and ▪ were found to have high capacities (with values of 370.41 and 317.12 mAhg−1, respectively) and be capable of adsorbing multiple Li layers on both sides. In addition, lower diffusion barriers were found on Se and Te sides compared with the O side. This study demonstrated that the creation of Janus structures enhances the electronic properties of Zr-based MXenes while maintaining their superior mechanical properties, rendering the materials more suitable for use as electrodes in lithium-ion batteries.

Electrochemical Properties of Powdery LiNi1/3Mn1/3Co1/3O2 Electrodes with Styrene-Acrylic-Rubber-Based Latex Binders at High Voltage.

Efforts to improve the energy density and cycling stability of lithium-ion batteries have focused on replacing LiCoO2 in cathodes with LiNixMnyCo1-x-yO2. However, reliance on polyvinylidene fluoride (PVdF) as the binder limits the application of the LiNixMnyCo1-x-yO2 composite electrode for lithium-ion batteries. Here, we evaluate the electrochemical properties of a LiNi1/3Mn1/3Co1/3O2 (NMC111) powder electrode formed using a waterborne-styrene-acrylic-rubber (SAR) latex binder combined with sodium carboxymethylcellulose. The composite electrodes prepared with the SAR-based binder copolymerized with the butyl acrylate monomer and styrene exhibited high adhesive strength and excellent cyclability and rate capability. The results of surface analysis via X-ray photoelectron spectroscopy suggested that the electrode with the SAR-based binder is more resistant to electrolyte decomposition during charge and discharge cycling compared with the NMC111 electrode comprising the conventional PVdF binder. The SAR-derived passivation resulted in enhanced capacity retention during long-term cycling tests of both half- and full-cells (NMC111//graphite). An electrode with a higher Ni content, LiNi0.6Mn0.2Co0.2O2 (NMC622), fabricated using the SAR-based binder, retained 87.1% of its capacity after 50 cycles at 4.6 V and exhibited excellent cycling stability.

Electrochemical synthesis and carbon doping of nanostructured iron fluorides from the selection of metal current collectors in lithium-ion batteries

The use of materials that rely on conversion reactions as electrodes in lithium-ion batteries is extensively investigated due to their potential for enhanced capacity compared to traditional electrode materials. Iron fluorides, in particular, present a promising alternative in terms of specific capacity. However, these materials often face challenges related to low intrinsic conductivity. This issue is typically addressed in the literature by doping the active material with carbon particles and reducing the particle size of the active material. This study explores the feasibility of directly integrating conductive carbon from the substrate into the fluoride-based active material during the synthesis process. The synthesis employs a simple anodic method conducted directly on the chosen metallic substrate, which then functions as the current collector in the devices. This approach simplifies the synthesis process, reduces processing time, and eliminates the need for additives and binders at the conventional active material-current collector interface. Two FeF3 layers were electrochemically synthesized on steel substrates with different carbon contents. These layers were evaluated as cathode-active materials for rechargeable lithium-ion batteries. The influence of carbon on the conductivity of the conversion layer was assessed using Electrochemical Impedance Spectroscopy (EIS) with a model based on conductive porous electrodes. Morphological and thickness analyses of the layers showed a strong correlation between increased pore size and layer thickness and the carbon content in the metallic substrate. The optimal performance was observed with the layer on the substrate with higher carbon content. The electrochemical performance of the active material was further evaluated using electrochemical impedance spectroscopy and galvanostatic tests in pouch cells. The conversion layers derived from carbon steel exhibited reduced resistivity and enhanced specific capacitance and cyclability compared to layers formed on pure iron.

Facile preparation of Co3O4/Super P/multi-walled carbon nanotube films for high-performance Li-ion battery anodes

This study prepared Co3O4/Super P/Multi-walled carbon nanotube (MWCNT) free-standing films through a simple vacuum filtration method. The free-standing films showed that Co3O4 particles were well dispersed within the Super P and MWCNT network backbone without deforming oxide materials, confirmed by scanning electron microscopy (SEM) images and X-ray diffraction (XRD) patterns. Employing Co3O4/Super P/MWCNT free-standing films as an anode electrode in lithium-ion batteries is superior to conventional electrode procedures because a binder is not required, and the current collector and laminate process are required. Moreover, the Co3O4/Super P/MWCNT electrodes showed remarkable capacity and rate capability compared to that of conventional laminated Co3O4/carbon composites. The enhanced electrochemical performance of Co3O4/Super P/MWCNT electrodes could be attributed to the extraordinary electrical conduction of MWCNT in nature and its stable connection between the conductive substrate and active materials. Furthermore, this connection offers the integrity of the electrode despite volume variation during Lithium (Li)-ion intercalation and deintercalation.

Application of nanotechnology in the negative electrode of Si-based lithium-ion batteries

Modern electronics and electric cars frequently employ lithium-ion batteries (LIBs) because of their excellent energy density, safety, and environmental friendliness. The anode of LIBs is typically composed of carbon. Nevertheless, it loses a lot of energy when charging and draining. Lithium metal precipitates quickly from the surface of carbon electrodes and forms dendrites. These can pass through the diaphragm and cause short circuits inside the battery, posing a public safety risk. The advantages of the silicon-based anode are excellent safety, low operating voltage, and high theoretical specific capacity. It is among the most critical potential materials for high-energy-density lithium-ion batteries. However, its drawbacks, such as volume expansion and poor electrical conductivity, limit the development of LIBs. In recent years, the emergence of nanotechnology has well solved these problems. This paper first explains how silicon-based lithium-ion batteries work and summarizes the challenges of silicon-based anodes. Then, it explores the application of nanotechnology in silicon-based anode, including different dimensions of silicon nanomaterials. After the group, the paper analyzes the shortcomings of current research and proposes future directions.

Design of Silicon-Based Anode Materials for High Energy Density Li-Ion Batteries

Compared to other types of batteries, lithium batteries have an extremely high energy density, which means they can store more energy while maintaining a smaller size and weight. The ideal electrode material must have a high lithium ion capacity to store many lithium ions. In addition, the electrode material must have good electronic conductivity to promote lithium ions' rapid entry and exit. However, traditional carbon materials have limited theoretical specific capacity, and the transmission of lithium-ion batteries in traditional materials is limited, resulting in a significant decrease in capacity. Silicon has a theoretical capacity of up to 4200mAh/g, more than ten times the capacity of commercial graphite negative electrodes. In addition, silicon and lithium can undergo alloying reactions to form Li Si alloys, which helps improve the material's specific capacity. This article first summarizes the advantages of electric vehicles and lithium-ion batteries. Then, the benefits and challenges of using silicon-based materials as negative electrodes for lithium-ion batteries were elaborated in detail, and finally, the prospects of silicon-based materials in lithium-ion battery applications were summarized. This article has reference significance in improving the energy density of lithium-ion batteries.

Effect of improved dispersibility of an MWCNT conductive material by oxyfluorination on the electrochemical performance of SiOx/C-based electrodes for lithium-ion batteries

Effect of improved dispersibility of an MWCNT conductive material by oxyfluorination on the electrochemical performance of SiOx/C-based electrodes for lithium-ion batteries

Exploring the potential and impact of single-crystal active materials on dry-processed electrodes for high-performance lithium-ion batteries

Roll-to-roll powder-to-film dry processing (DP) and single-crystal (SC) active materials (AMs) with many advantages are two hot topics of lithium-ion batteries (LIBs). However, DP of SC AMs for LIBs is rarely reported. Consequently, the impact of SC AMs on dry-processed LIBs is not well understood. Herein, for the first time, via a set of experimental and theoretical studies of the conventional polycrystalline-AM- and SC-AM-based DPed electrodes (DPEs), this work not only reports a high-performance dry SC-AM cathode for LIB manufacturing, but also establishes some fundamental understanding of SC-based dry-processed electrodes, including their morphology, structure, mechanical strength, electronic conductivity and LIB electrochemical behavior. The results suggest that DP of SC AMs is promising, which can dramatically improve the electrochemical kinetics at electrode level and particle level. Specifically, for the rate capability and long-term cyclability in full cells, SC DPEs exhibit a discharge specific capacity of 152.1 mAh g−1 at 1C and a capacity retention rate of 79.9 % at C/3 over 500 cycles, which are superior to those of PC DPEs (135.6 mAh g−1 and 68.3 %) at the same conditions and are further confirmed by the simulation data from the theoretical modelling study. Therefore, this comprehensive work marks a significant milestone for DP strategy and SC AMs, enlightening future research and development of LIB manufacturing.

Rice straw -derived lignin-based carbon nanofibers as self-supporting electrodes for supercapacitors and lithium-ion batteries

Self-supporting carbon fibers are extensively employed as active components in energy storage systems due to their tunable microstructures, large specific surface area, affordability, and excellent electrical conductivity. Nevertheless, conventional methods for producing carbon fibers typically involve complicated synthesis processes, environmental pollution, and high energy consumption. In this study, lignin-based carbon nanofibers (LCNFs) were prepared through electrospinning and subsequent heat treatment. The morphologies, crystal structures, and specific surface area of the as-prepared LCNFs were characterized using scanning electron microscopy, X-ray diffraction and nitrogen sorption isotherms. The influence of lignin content on the on the structural, morphological, and electrochemical properties of the carbon nanofibers were examined, particularly in their applications as supercapacitor and lithium-ion battery anode materials. The as-prepared LCNF-2 possess the highest specific surface area of 468.3 m2 g−1. As a self-supporting electrode in supercapacitors (SCs), the LCNF-2 delivered 256.3 F g−1 at 0.2 A g−1, and capacitance retention of 62.0 % at the current density raised from 0.5 to 10 A g−1. The assembled LCNF-2//LCNF-2 symmetric supercapacitor demonstrated a specific capacitance of 168 F g−1 at 5 A g−1, maintaining 100 % capacitance retention after 10,000 cycles. Additionally, it achieved an energy density of 5.6 Wh kg−1 at a power density of 1250.0 W kg−1. As a lithium-ion batteries (LIBs) anode, the LCNF-2 showed a discharge specific capacity of 1108.3 mAh g−1 and a discharge specific capacity of 377.3 mAh g−1 in the first cycle, with a capacity retention rate of 84.6 % after 100 cycles at 1C. This work offers a novel approach for the high-value utilization of agricultural waste straw lignin in energy storage devices.

INSIGHTS INTO THE ELECTROCHEMICAL PROPERTIES OF GERMANIUM-COBALT-INDIUM NANOSTRUCTURES IN A WIDE TEMPERATURE RANGE

Germanium-cobalt-indium (Ge-Co-In) nanostructures are a promising material for negative electrodes of lithium-ion batteries aimed for arctic exploitation. Electrochemical impedance spectroscopy was used for a detailed study of the interaction of Ge-Co-In nanostructures with lithium in a temperature range from ‒35 to +20°C. The discharge capacity at temperatures of 20, 0, ‒10, ‒20, and ‒35°C amounted to 1400, 1228, 1040, 907, and 793 mAh g‒1, respectively. The impedance spectra measured at various lithiation degrees were found to differ but insignificantly whereas temperature variation resulted in notable changes in the spectra. A normalized charge transfer resistance for Ge-Co-In nanostructures was significantly (more than an order of magnitude) less than for Ge-In nanowires (obtained by the same method, but without the addition of cobalt salt into the electrolysis solution). It is this difference in charge transfer resistance that can explain the difference in the shapes of the impedance spectra for both objects. Also, in contrast to data for Ge-In nanowires, the dependences of the lithium diffusion coefficient in Ge-Co-In nanostructures on potential had a clearly defined minimum. The lithium diffusion coefficient in Ge-Co-In nanostructures slightly exceeded that in Ge-In nanowires, and the activation energy of lithium diffusion in Ge-Co-In nanostructures was marginally less than in Ge-In nanowires.

Enhanced cycling stability of silicon electrode for lithium-ion batteries by dual hydrogen bonding mediated by carboxylated carbon nanotube

Carbon nanotubes (CNTs) are being used as high-performance conductive agents for fast electron transport and effective suppression of volume change in silicon (Si) electrode. However, utilization of CNTs has significant challenges, including poor dispersibility and weak interaction with Si particles. Herein, carboxylated CNTs (CNT-COOH) are employed as a mediator to form dual hydrogen bonds with the tannic acid-coated Si particles (Si@TA) and carboxymethyl cellulose (CMC) binder, through which all the constituents (active material, conductive agent, and binder) comprising the electrode are strongly connected. Also, CNT-COOH strongly attaches to Si@TA via π-π conjugation. Furthermore, the TA-coating layer serves as a protective layer from the electrolyte. As a result, the Si@TA/CNT-COOH composite electrode shows excellent cycling stability delivering a discharge-specific capacity of 1287 mAh g-1 after 200 cycles at 2 A g-1 and retains 1916 mAh g-1 even at high current density of 10 A g-1. The structural integrity of the Si@TA/CNT-COOH electrode is also confirmed by less deformation and thickness change after cycling.

Enhancing Precision and Durability of Built-In Cu-Li Reference Electrodes in Lithium-Ion Batteries: A Critical Review

Enhancing Precision and Durability of Built-In Cu-Li Reference Electrodes in Lithium-Ion Batteries: A Critical Review

Machine learning-assisted DFT-prediction of pristine and endohedral doped (O and Se) Ge12C12 and Si12C12 nanostructures as anode materials for lithium-ion batteries

Nanostructured materials have gained significant attention as anode material in rechargeable lithium-ion batteries due to their large surface-to-volume ratio and efficient lithium-ion intercalation. Herein, we systematically investigated the electronic and electrochemical performance of pristine and endohedral doped (O and Se) Ge12C12 and Si12C12 nanocages as a prospective negative electrode for lithium-ion batteries using high-level density functional theory at the DFT/B3LYP-GD3(BJ)/6-311 + G(d, p)/GEN/LanL2DZ level of theory. Key findings from frontier molecular orbital (FMO) and density of states (DOS) revealed that endohedral doping of the studied nanocages with O and Se tremendously enhances their electrical conductivity. Furthermore, the pristine Si12C12 nanocage brilliantly exhibited the highest Vcell (1.49 V) and theoretical capacity (668.42 mAh g− 1) among the investigated nanocages and, hence, the most suitable negative electrode material for lithium-ion batteries. Moreover, we utilized four machine learning regression algorithms, namely, Linear, Lasso, Ridge, and ElasticNet regression, to predict the Vcell of the nanocages obtained from DFT simulation, achieving R2 scores close to 1 (R2 = 0.99) and lower RMSE values (RMSE < 0.05). Among the regression algorithms, Lasso regression demonstrated the best performance in predicting the Vcell of the nanocages, owing to its L1 regularization technique.

Powder Compaction Characteristics and Modeling of Calendering Process for Powder-based Solvent-free Manufacturing of Electrodes for Lithium-ion Batteries

Abstract Powder-based solvent-free manufacturing of electrodes for Li-ion batteries represents an emerging and promising technology in electrode fabrication. This method involves a two-roll powder calendering process, where electrode powder materials are compressed onto a current collector to form electrodes with desired properties. The calendering or compaction of dry powders onto a current collector is a crucial step in solvent-free electrode manufacturing, significantly impacting the microstructures, mechanical properties, and electrochemical performance of the produced electrodes. In this paper, we investigate the compaction characteristics of electrode powders to gain insights into their behavior. A powder-on-current collector calendering model is developed based on Johanson's rolling theory of granular solids. This model enables us to infer the underlying calendering parameters essential for the solvent-free manufacturing of Li-ion batteries. To validate the model, we compare it with experimental calendering results, utilizing measured powder properties and roll design parameters as inputs. This approach offers a comprehensive understanding of the effects of roll geometries, particularly roll diameter, and various equipment design parameters on final electrode properties. Such insights have not been thoroughly explored in the emerging field of solvent-free battery electrode manufacturing, thereby contributing to advancements in this area.

High-fidelity reconstruction of porous cathode microstructures from FIB-SEM data with deep learning

Accurate modeling of lithium-ion battery (LIB) electrode microstructures provides essential references for understanding degradation mechanisms and optimizing materials. Traditional segmentation methods often struggle to accurately capture the complex microstructures of porous LIB electrodes in focused ion beam scanning electron microscopy (FIB-SEM) data. In this work, we develop a deep learning model based on the Swin Transformer to segment FIB-SEM data of a lithium cobalt oxide electrode, utilizing fused secondary and backscattered electron images. The proposed approach outperforms other deep learning methods, enabling the acquirement of 3D microstructure with reduced particle elongated artifacts. Analyses of the segmented microstructures reveal improved electrode tortuosity and pore connectivity crucial for ion and electron transport, emphasizing the necessity of accurate 3D modeling for reliable battery performance predictions. These results suggest a path toward voxel-level degradation analysis through more sensible battery simulation on high-fidelity microstructure models directly twinned from real porous electrodes.

Pseudo Two-Dimensional Model for the Design of Fast-Charging Lithium-Ion Battery Electrodes

Pseudo Two-Dimensional Model for the Design of Fast-Charging Lithium-Ion Battery Electrodes