Silicon Anodes In Lithium-ion Batteries Research Articles

Progress in the application of silicon-based materials in lithium-ion batteries anodes

From the battery that powers the remote control to the battery that powers electric cars, lithium-ion batteries (LIBs) are a crucial component of contemporary energy storage. The large theoretical capacity of silicon anodes provides significant benefits inside LIBs. However, the main issue with the conventional silicon bulk anode is its considerable volume expansion, which forms an unstable Solid Electrolyte Interface (SEI) layer during the charge and discharge process and severely reduces battery performance and lifespan. Therefore, to solve these issues, researchers have explored multiple improved silicon anodes, three of which are mentioned in this essay. Firstly, the researchers delve into the usage of nanotechnology. When manipulating silicon particles at the nano-scale, the nano-silicon can mitigate the volume expansion, improving the reaction kinetics. Then, a composite of carbon and silicon is proposed, combining silicon's high capacitance and carbon's high conductivity. After that is the silicon-metal composite, which utilizes metals' mechanical strength and conductivity to stabilize Si anodes further and improve thermal stability. Overall, the significance of this study lies in the exploration of the application of silicon anodes in LIBs, highlighting the potential of these composite materials and advanced technology, which may help guide the future exploration of better silicon anodes.

In situ catalyzed growth of carbon nanotube with asphalt cladding as a bicarbon synergistic framework of silicon anodes for lithium-ion batteries.

Silicon, as the most promising advanced anode material for lithium-ion batteries, faces challenges in large-scale industrial production due to the significant volume expansion effect. In this investigation, Si/CNTs/C composite materials were effectively produced through high-temperature carbonization utilizing asphalt, silicon, hexahydrate ferric chloride, and melamine as primary elements. The distinctive dual-carbon framework of asphalt-derived carbon and carbon nanotubes alleviates the volume expansion of silicon, thereby stabilizing the composite material's structure. Testing the electrochemical performance reveals that the Si/CNTs/C composite material exhibits a reversible specific capacity of 1187 mAh g-1 with a capacity retention rate of 92.6% after 150 cycles at a current density of 0.2 A g-1. Even after 500 cycles at a current density of 1 A g-1, it sustains a specific capacity of 879.4 mAh g-1 with a capacity retention rate of 87.9%, showcasing outstanding electrochemical performance.

Electrochemical in-situ lithiated Li2SiO3 layer promote high performance silicon anode for lithium-ion batteries

Si anode is considered to be one of the most promising candidates for the next-generation lithium-ion batteries (LIBs). However, the severe volume variation of Si (> 300%) during the lithiation/delithiation process results in unstable interface and thus contributes to poor cycling stability. Moreover, the relatively low conductivity derived from the semiconductor nature of Si leads to inferior rate performance. Herein, Li2SiO3 layer with fast lithium-ions transport capability and high mechanical property was formed on Si surface in an in-situ electrochemical method. The relationships between the valence of SiOx and LixSiOy constituents were readily studied. Fortunately, the as-prepared Si@ES-LSO showed great potential to mitigate the expansion and high lithium-ions diffusion coefficient. When employed as anode materials for LIBs, the modified Si anode delivered a specific capacity of 2074.8 mAh g−1 at 1000 mA g−1 with a retention ratio of 98.9% after 100 cycles, demonstrating superior electrochemical performance. This work provides a facial and efficient strategy for the roadmap of Si anode application.

Interaction of Boron-Based Cross-Linkers with Polymer Binders for Silicon Anodes in Lithium-Ion Batteries

Interaction of Boron-Based Cross-Linkers with Polymer Binders for Silicon Anodes in Lithium-Ion Batteries

Advances in Coating Materials for Silicon-Based Lithium-Ion Battery Anodes

Silicon anodes, which exhibit high theoretical capacity and very low operating potential, are promising as anode candidates that can satisfy the conditions currently required for secondary batteries. However, the low conductivity of silicon and the alloying/dealloying phenomena that occur during charging and discharging cause sizeable volume expansion with side reactions; moreover, various electrochemical issues result in inferior cycling performance. Therefore, many strategies have been proposed to mitigate these problems, with the most commonly used method being the use of nanosized silicon. However, this approach leads to another electrochemical limitation—that is, an increase in side reactions due to the large surface area. These problems can effectively be resolved using coating strategies. Therefore, to address the issues faced by silicon anodes in lithium-ion batteries, this review comprehensively discusses various coating materials and the related synthesis methods. In this review, the electrochemical properties of silicon-based anodes are outlined according to the application of various coating materials such as carbon, inorganic (including metal-, metal oxide-, and nitride-based) materials, and polymer. Additionally, double shells introduced using two materials for double coatings exhibit more complementary electrochemical properties than those of their single-layer counterparts. The strategy involving the application of a coating is expected to have a positive effect on the commercialization of silicon-based anodes.

The Synergistic Effect of Cross-Linked and Electrostatic Self-Assembly Si/MXene Composites Anode for Highly Efficient Lithium-Ion Battery

Silicon is a promising anode material for high-performance lithium-ion batteries (LIBs), but its rapid capacity degradation has significantly hindered its large-scale application. In this study, we propose an in situ self-assembly polymerization method to fabricate a stable silicon-based anode by leveraging electrostatic self-assembly technology, in situ esterification, and amidation reactions. The incorporation of a cross-linked polymer, combined with the synergistic effects of electrostatic interactions between negatively charged MXene and positively charged silane-coupling-agent-modified silicon, offers a novel strategy for enhancing the electrochemical performance of LIBs. Notably, annealed electrodes with a 65 wt% nmSi-NH2/MXene ratio demonstrate outstanding electrochemical performance, achieving a capacity of 929.5 mAh g⁻¹ at a current density of 1 A g⁻¹ after 100 charge/discharge cycles. These findings suggest that the integration of cross-linked polymers and electrostatic self-assembly can significantly improve the intercalation and overall electrochemical performance of silicon anodes in lithium-ion batteries.

Overlooked challenges of interfacial chemistry upon developing high energy density silicon anodes for lithium-ion batteries

Evaluation of silicon (Si) anode performance by the assembled Si||Li half-cells is the primary approach in the development of high-energy-density lithium-ion batteries (LIBs). However, most studies focus solely on the variations of Si anode, the stability of electrolyte on the lithium (Li)-metal counter electrode has been overlooked. Herein, we discovered that the acquired cell performance not only depends on the Li+ (de-)solvation behaviors on the Si anode surface but also was affected significantly by the lithiation overpotential caused by the side reactions on the Li electrode. It is significant to identify this point, as these influences of electrolyte decomposition on the Li electrode have been previously regarded as an integral part of side reactions on the Si anode. We proposed a new perspective of the electrolyte solvation structure and electrode interfacial model to unravel the interfacial behaviors on the Si and Li electrodes respectively. The identified differences in the Li+ solvation and (de-)solvation behaviors not only provide reasons for the varied electrolyte stability in different electrolytes but also interpret the superior performance in tetrahydrofuran (THF)-based electrolytes. This study underscores the importance of understanding electrolyte behavior at the interfaces of individual electrodes to discern the reliability of electrode performance and also introduce a novel principle for designing superior electrolytes for high-energy-density LIBs.

Reactive force-field simulation and experimental validation of cyclic defects in silicon anodes for lithium-ion batteries

Reactive force-field simulation and experimental validation of cyclic defects in silicon anodes for lithium-ion batteries

Impact of Binder Thin-Films on Surface Chemistry of Silicon Anodes in Lithium-Ion Batteries

The effect of polymer binder on the nature and location of solid-electrolyte interphase (SEI) formation on Si active material was investigated. Thin layers of polymeric binder (polyvinylidene fluoride and sodium carboxymethyl cellulose) were spin-coated onto polished single crystal Si wafers. The samples were cycled against a Li counter/reference electrode under various electrochemical conditions in a coin cell configuration. The electrolyte was 1 M of LiPF6 in 1:1:1 wt% EC:DEC:DMC. After cycling, the samples were extracted from the coin cell under inert conditions and X-ray photoelectron spectroscopy (XPS) was performed. Electron microscopy and atomic force microscopy indicate that the binder films are smooth and continuous across the wafer surface, and no impact on the electrochemical behavior was observed. However, notable differences were detected using XPS, which revealed both difference in SEI composition and location relative to the binder-electrolyte and binder-substrate interfaces. These observations and insights will be useful in cell designs, binder selection, and reliability estimates because the location of SEI formation may influence cyclic performance of electrodes.

Effect of Water–Soluble Polyimide (w-PI) Type Binders on the Performance of High-Capacity Silicon Anodes of Lithium-Ion Batteries

In order to enhance rapid charging and driving range for electric vehicles, the high-capacity of lithium-ion batteries (LIBs) is imperative. Commercially available graphite as an anode material has long cycle life, abundance, and low cost. However, it has a limitation in its theoretical specific capacity (372 mAh g−1).To overcome this limitation, much attention has been paid to silicon (Si), which offers a high theoretical specific capacity of 4,200 mAh g−1. Nevertheless, silicon suffers from excessive volume expansion, resulting in issues such as pulverization of active alloy particles, delamination, and the formation of an unstable Solid Electrolyte Interphase layer. This lead to a limitation to use the silicon in large amount in an electrode. A polymeric binder has a critical role in improving the high-capacity Si anode. Conventional polyimide (PI), one of various super-engineering plastics, was applied to the Si anodes, but it is still challenged to water-insolublity and high temperature imidization process around 300 oC. In this study, a water-soluble PI (w-PI) is designed by the polycondensation between dianhydrides and diamine in water environment. In addition, a relatviely low-temperature imidization temperature below 200 oC will be appled by the introduction of dimethylimidazole. This study will briefly outline the direction for implementing a w-PI binder and improving electrochemical performance of high-capacity anode compared to conventional binders such as PVdF and CMC/SBR. Keyword: high-capacity Si anode; dianhydrides and diamine; Polyimide (PI); and water-soluble PI Figure 1

Designing Stable Nanoparticles for Deforming Silicon Anodes in Lithium Ion Batteries

Silicon anodes in lithium-ion batteries are a promising next-generation battery technology offering ten times higher theoretical capacity than commercial graphite anodes. However, substantial volume changes (around 300%) associated with silicon anodes pose a significant challenge to the cycle life of these batteries. To understand the effect of the interaction between lithiation (diffusion) and mechanics (volume expansion, stress generation) on cycle life, a theoretical chemo-mechanical model of an isolated deforming silicon anode nanospherical particle is proposed in this study. Existing models, designed for low-capacity electrode materials, ignore the effect of deforming volume in the model formulation. Deforming volume, critical for high-capacity electrodes like silicon, is accounted for in the proposed model. Galvanostatic and potentiostatic operating conditions are considered. Simulations of the model help explain the importance of smaller particle sizes in observed longer cycle lives of silicon anodes. These enable mathematically accurate calibration of the partial molar volume of the material and determination of the developed mechanical stresses. Simulations of the proposed model help us optimize design parameters like particle size, particle thickness, and the charge rate/ applied voltage for elastic operation to ensure longer cycle lives of these batteries. Figure 1

A Triple Crosslinked Binder with Hierarchical Stress Dissipation and High Ionic Conductivity for Advanced Silicon Anodes in Lithium-ion Batteries.

Silicon (Si) is a promising anode material for high-energy-density lithium-ion batteries, but the significant volume change of Si particles during alloying/dealloying with lithium (Li) undermines the mechanical integrity of Si anode, causing electrode fracture, delamination and rapid capacity decay. Herein, a robust triple crosslinked network (TCN) binder with high ionic conductivity and hierarchical stress dissipation is reported for Si anodes, which is prepared by in situ chemical crosslinking polyacrylic acid (PAA) and melamine (MA). The triple interactions of hydrogen bonds, electrostatic interactions, and covalent amide bonds enhance the adhesion of binder to Si and synergistically promote stress dissipation within Si anodes, thus strengthening the dynamic structural stability of Si anodes during cycling. Moreover, the rapid coupling/decoupling of Li+ with the TCN binder enables an impressive Li+ transference number of 0.63 and high ionic conductivity of 1.2 × 10-4 Scm-1. Consequently, the Si-TCN anode delivers specific capacity of 2268 mAhg-1 with a high mass loading of 2mgcm-2, high-rate performance of 1673 mAhg-1 at 5 Ag-1, and stable cycling for 250 cycles at 1 Ag-1, thus showing great prospects for high-energy-density Si-based batteries.

Rigid-flexible mediated Co-polyimide enabling stable silicon anode in lithium-ion batteries

Silicon is considered as a promising electrode materials for the next generation of lithium-ion batteries. However, it’s commercial applications are hindered by significant volume changes. In this study, copolyimide binders with adjustable rigidity and flexibility were synthesized through simple copolymerization. The rigid segments containing adenine groups (p-APA) provide excellent mechanical strength and interface interaction, while flexible segments containing siloxane bonds and alkane chains (DS-NH2) can buffer volume changes through enhanced mobility and topological entanglement of molecular segments. Optimizing the copolymerization ratio helps minimize damage to the silicon electrode structure and stabilizes solid electrolyte interphase (SEI) growth. Compared to the rigid polyimide binders, rigid-flexible coupling strategy improves cycling stability, remaining a capacity of 2170 mAh/g at 2 A/g after 200 cycles and exhibiting stable cycling for over 750 cycles with a capacity limitation of 1500 mAh/g. The high mass loading silicon anodes, micron-sized silicon oxide electrodes and the full cells also exhibit favorable electrochemical performance. This research provides valuable insights for designing high-performance aromatic polymer binders for high energy density lithium-ion batteries.

Understanding solid electrolyte interface formation on graphite and silicon anodes in lithium-ion batteries: Exploring the role of fluoroethylene carbonate

This study explores how fluoroethylene carbonate (FEC) influences the solid electrolyte interface (SEI) layer formation during battery cycling process. FEC improves SEI properties, producing a uniform, chemically stable layer enriched with lithium fluoride. This enhances mechanical resilience and electrochemical stability. FEC also suppresses electrolyte deformation and decomposition, maintaining its initial state. The findings highlight the significance and comprehension of electrolyte additives, offering an electrolyte research pathway for improving Li-ion battery performance and durability.

Novel Binder with Cross-Linking Reconfiguration Functionality for Silicon Anodes of Lithium-Ion Batteries.

Silicon is expected to be used as a high theoretical capacity anode material in lithium-ion batteries with high energy densities. However, the huge volume change incurred when silicon de-embeds lithium ions, leading to destruction of the electrode structure and a rapid reduction in battery capacity. Although binders play a key role in maintaining the stability of the electrode structure, commonly used binders cannot withstand the large volume expansion of the silicon. To alleviate this problem, we propose a PGC cross-linking reconfiguration binder based on poly(acrylic acid) (PAA), gelatin (GN), and β-cyclodextrin (β-CD). Within PGC, PAA supports the main chain and provides a large number of carboxyl groups (-COOH), GN provides rich carboxyl and amide groups that can form a cross-linking network with PAA, and β-CD offers rich hydroxyl groups and a cone-shaped hollow ring structure that can alleviate stress accumulation in the polymer chain by forming a new dynamic cross-linking coordination conformation during stretching. In the half cell, the silicon negative prepared by the PGC binder exhibited a high specific capacity and capacity maintenance ratio, and the specific capacity of the silicon negative electrode prepared by the PGC binder is still 1809 mAh g-1 and the capacity maintenance ratio is 73.76% following 200 cycles at 2 A g-1 current density, indicating that PGC sufficiently maintains the silicon negative structure during the battery cycle. The PGC binder has a simple preparation method and good capacity retention ability, making it a potential reference for the further development of silicon negative electrodes.

Steric molecular combing effect enables Self-Healing binder for silicon anodes in Lithium-Ion batteries

Silicon is a promising anode material for lithium-ion batteries with its superior capacity. However, the volume change of the silicon anode seriously affects the electrode integrity and cycle stability. The waterborne guar gum (GG) binder has been regarded as one of the most promising binders for Si anodes. Here, a unique steric molecular combing approach based on guar gum, glycerol, and citric acid is proposed to develop a self-healing binder GGC, which would boost the structural stability of electrode materials. The GGC binder is mainly designed to weaken van der Waals' forces between polymers through the plasticizing effect of glycerol, combing and straightening the guar molecular chain of GG, and exposing the guar hydroxyl sites of GG and the carboxyl groups of citric acid. The condensation reaction between the hydroxyl sites of GG and the carboxyl groups of citric acid forms stronger hydrogen bonds, which can help achieve self-healing effect to cope with the severe volume expansion effect of silicone-based materials. Silicon electrode lithium-ion batteries prepared with GGC binders exhibit outstanding electrochemical performance, with a discharge capacity of up to 1579 mAh/g for 1200 cycles at 1 A/g, providing a high capacity retention rate of 96%. This paper demostrates the great potential of GGC binders in realizing electrochemical performance enhancement of silicon anode.

Designing Compatible Ceramic/Polymer Composite Solid-State Electrolyte for Stable Silicon Nanosheet Anodes.

The commercialization of silicon anode for lithium-ion batteries has been hindered by severe structure fracture and continuous interfacial reaction against liquid electrolytes, which can be mitigated by solid-state electrolytes. However, rigid ceramic electrolyte suffers from large electrolyte/electrode interfacial resistance, and polymer electrolyte undergoes poor ionic conductivity, both of which are worsened by volume expansion of silicon. Herein, by dispersing Li1.3Al0.3Ti1.7(PO4)3 (LATP) into poly(vinylidene fluoride)-hexafluoropropylene (PVDF-HFP) and poly(ethylene oxide) (PEO) matrix, the PVDF-HFP/PEO/LATP (PHP-L) solid-state electrolyte with high ionic conductivity (1.40 × 10-3Scm-1), high tensile strength and flexibility is designed, achieving brilliant compatibility with silicon nanosheets. The chemical interactions between PVDF-HFP and PEO, LATP increase amorphous degree of polymer, accelerating Li+ transfer. Good flexibility of the PHP-L contributes to adaptive structure variation of electrolyte with silicon expansion/shrinkage, ensuring swift interfacial ions transfer. Moreover, the solid membrane with high tensile limits electrode structural degradation and eliminates continuous interfacial growth to form stable 2D solid electrolyte interface (SEI) film, achieving superior cyclic performance to liquid electrolytes. The Si//PHP-L15//LiFePO4 solid-state full-cell exhibits stable lithium storage with 81% capacity retention after 100 cycles. This work demonstrates the effectiveness of composite solid electrolyte in addressing fundamental interfacial and performance challenges of silicon anodes.

Dynamic mechanical equilibrium of silicon anodes for lithium-ion batteries enabled by surface hydroxyl-rich bonding

The dynamic mechanical equilibrium strategy effectively suppresses the severe volume expansion of silicon anodes, achieving excellent cycle stability.

Nanoarchitectonics of 3D-networked bio-based binders for silicon anodes in lithium-ion batteries based on dynamic hydrogen bonding

A bio-based binder was developed to improve the electrochemical performance of silicon-anode lithium-ion batteries.

Dynamic hydrogen bond cross-linking binder with self-healing chemistry enables high-performance silicon anode in lithium-ion batteries

The structure instability and cycling decay of silicon (Si) anode triggered by stress buildup hinder its practical application to next-generation high-energy–density lithium-ion batteries (LIBs). Herein, a cross-linking polymeric network as a self-healing binder for Si anode is developed by in situ polymerization of tannic acid (TA) and polyacrylic acid (PAA) binder labelled as TA-c-PAA. The branched TA as a physical cross-linker complexes with PAA main chains through abundant dynamic hydrogen bonds, endowing the cross-linking TA-c-PAA binder with unique self-healing property and strong adhesion for Si anode. Benefiting from the mechanical robust and hard adhesion, the Si@TA-c-PAA electrode exhibits high reversible specific capacities (3250 mAh/g at 0.05C (1C = 4000 mA g−1)), excellent rate capability (1599 mAh/g at 2C), and impressive cycling stability (1742 mAh/g at 0.25C after 450 cycles). After Ex situ morphology characterization, in situ swelling analysis, and finite element simulation, it is found that the TA-c-PAA binder allows the Si anode to dissipate stress and prevent pulverization during lithiation and delithiation, thus the hydrogen bonds among interpenetrating network may be adaptable to the stress intensity. Our work paves a new avenue for the design of efficient and cost-effective binders for next-generation Si anode in LIBs.