Anode For Lithium-ion Batteries Research Articles

Dynamic magnesiothermic reduction of various silica to porous silicon structures for lithium battery anodes

A dynamic magnesiothermic reduction (DMR) of various silica having different size and porosity is conducted to study the effects of silica properties on the ⅰ) DMR reaction kinetics, ⅱ) properties of resulting porous silicon (pSi) microparticles, and ⅲ) performances of pSi/C composites as anodes in lithium batteries. A DMR kinetic study using the Ginstling–Brounstein diffusion model shows that the smaller the silica particle size, the higher the reduction rate and the lower the apparent activation energy. Irrespective of silica properties, all the resulting pSi particles have mesoporous structures. The pSi particles comprise interconnected small primary silicon nanoparticles (approximately 30–40 nm in diameter) to render similar particle morphologies to those of the parent silica. Owing to these appealing features of pSi particles, pSi/C composites exhibit excellent cycling performance for over 200 cycles and high rate capabilities, whereas SiMP/C (prepared with a non-porous silicon microparticles) loses most of its capacity in early cycles owing to high resistance build-up during cycling. Overall, the DMR of silica precursors of several micrometers or less in size (preferably porous precursors) are desirable for the production of high-purity pSi microparticles for use in high-capacity and stable anodes for advanced lithium batteries.

SnS nanoflowers as an efficient anode for next generation lithium-ion batteries

Tin (II) Sulfide (SnS) nanoflowers are synthesized by hydrothermal method. The electrochemical performance of SnS nanoflower versus Li/Li+ is studied. X-ray diffraction and X-ray photoelectron spectroscopy results confirms the formation of SnS. Scanning electron microscope images validate the existence of nanoflowers. SnS vs. Li/Li+ half-cell delivers the first charge/discharge capacity of 847.2/853 mAh g−1 at 0.1 C-rate, with a columbic efficiency of 99 %. Differential capacity versus voltage plot reveals intercalation and deintercalation of lithium ions during cycling and also delves the conversion and alloying reaction of SnS anodes. The better electrochemical result could be ascribed to the flower like morphology, which improves lithium diffusion and reaction kinetics.

Densification of Alloying Anodes for High Energy Lithium-Ion Batteries: Critical Perspective on Inter- Versus Intra-Particle Porosity.

High Li-storage-capacity particles such as alloying-based anodes (Si, Sn, Ge, etc.) are core components for next-generation Li-ion batteries (LIBs) but are crippled by their intrinsic volume expansion issues. While pore pre-plantation represents a mainstream solution, seldom do this strategy fully satisfy the requirements in practical LIBs. One prominent issue is that porous particles reduce electrode density and negate volumetric performance (WhL-1) despite aggressive electrode densification strategies. Moreover, the additional liquid electrolyte dosage resulting from porosity increase is rarely noticed, which has a significant negative impact on cell gravimetric energy density (Whkg-1). Here, the concept of judicious porosity control is introduced to recalibrate existing particle design principles in order to concurrently boost gravimetric and volumetric performance, while also maintaining the battery's cycle life. The critical is emphasized but often neglected role that intraparticle pores play in dictating battery performance, and also highlight the superiority of closed pores over the open pores that are more commonly referred to in the literature. While the analysis and case studies focus on silicon-carbon composites, the overall conclusions apply to the broad class of alloying anode chemistries.

ZIF-derived "cocoon"-like in-situ Zn/N-doped carbon as high-capacity anodes for Li/Na-ion batteries

Owing to the unique structure and physicochemical properties, including high specific surface area, self-doped N atoms, open pore structure and good chemical stability, zeolitic imidazolate frameworks (ZIFs) and their derivatives have been widely used in the field of energy storage. Here, a new type of "cocoon"-like Zn/N doped ZIF-derived porous carbon (Zn@N-C-800) is synthesized as an anode for lithium-ion batteries (LIBs) and sodium ion batteries (SIBs) through a one-step carbonization process using a novel Zn-ZIF as the precursor. In Zn@N-C-800, the "cocoon"-like disordered carbon skeleton is conducive to electrolyte infiltration, while the Zn/N doping can provide additional active sites for ion storage. Benefiting from these unique structural characteristics, Zn@N-C-800 achieves excellent electrochemical performances as anode for both LIBs and SIBs: an ultrahigh rate capability of 352 mAh g−1 can be delivered at 12.8 A g−1 for LIBs; an outstanding long-term cycling stability (312 mAh g−1 at 1 A g−1 after 2000 cycles) can be achieved for SIBs. This paper provides new ideas for the design and preparation of high-performance anodes for LIBs and SIBs.

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.

High-stable and High-capacity Sn/SnO2@C as Anode of Lithium-ion Batteries

High-stable and High-capacity Sn/SnO2@C as Anode of Lithium-ion Batteries

Binder-dependent electrochemical properties of high entropy oxide anodes for lithium-ion batteries

High entropy oxide (HEO) materials have recently emerged as promising anodes for lithium-ion batteries (LIBs). In this study, we conduct the first comparative analysis to investigate the influence of various electrode binders on electrochemical properties of (CrMnFeNiCu)3O4 HEO anodes. The organic-solvent-soluble polyvinylidene fluoride and water-soluble polyvinyl formamide, sodium carboxymethyl cellulose, sodium alginate, and sodium polyacrylate (NaPAA) binders are examined. Notably, the NaPAA binder leads to a significant enhancement in the HEO performance. The NaPAA coating on (CrMnFeNiCu)3O4 effectively improves the electrode charge-discharge Coulombic efficiency and mitigates the electrode deterioration. Binder adhesion strength and stability toward electrolyte are assessed. The charge-transfer resistance and apparent Li+ diffusion of the HEO electrodes with various binders, accompanied by the post-cycling analyses, are examined. By employing the NaPAA binder, exceptional electrode capacities of 800 and 495 mAh g–1 are attained at charge-discharge rates of 50 and 2000 mA g–1, respectively, without noticeable capacity degradation after 300 cycles. The thermal reactivity of the lithiated electrodes is investigated using differential scanning calorimetry, and the impact of binders on the electrode exothermic onset temperature and total heat released is studied. Our findings provide valuable insights for enhancing the performance and safety of HEO anodes for LIBs.

Co-Assembly of Polyoxometalates and Porphyrins as Anode for High-Performance Lithium-Ion Batteries.

Polyoxometalates (POMs) have been considered one of the most promising anode candidates for lithium-ion batteries (LIBs) in virtue of their high theoretical capacity and reversible multielectron redox properties. However, the poor intrinsic electronic conductivity, low specific surface area, and high solubility in organic electrolytes hinder their widespread applications in LIBs. Herein, a novel hybrid nanomaterial is synthesized by co-assembling POMs and porphyrins (PMo12/CoTPyP) through a facile solvothermal method. The POM clusters are stabilized by porphyrin units through electrostatic interactions, which simultaneously realize the uniform dispersion of POMs and porphyrin units. Benefiting from the generated sub-1nm channels for fast ion transport and the synergistic effect between evenly distributed PMo12 clusters and high-conductive CoTPyP units, the LIB based on the optimized PMo12/CoTPyP anode exhibits significantly improved Li+ storage capability as well as superior rate and cycling performance. The results of density functional theory simulations further reveal that the co-assembly of PMo12 and CoTPyP can accelerate the mobility of Li+ and electrons, which in turn promotes the enhancement of LIBs performance. This work paves a strategy for synthesizing POMs-based anode materials with simultaneously high dispersibility, redox activity, and stability.

Polymer-Supported Graphene Sheet as a Vertically Conductive Anode of Lithium-Ion Battery.

The increasing demand for electric vehicles necessitates the development of cost-effective, mass-producible, long-lasting, and highly conductive batteries. Making this kind of battery is exceedingly tricky. This study introduces an innovative fabrication technique utilizing a laser-induced graphene (LIG) approach on commercial Kapton film to create hexagonal pores. These pores form vertical conduction paths for electron and ion transportation during lithiation and delithiation, significantly enhancing conductivity. The nongraphitized portion of the Kapton film makes it a binder-less, free-standing electrode, providing mechanical stability. Various analytical techniques, including scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), Raman spectroscopy, and atomic force microscopy (AFM) are utilized to confirm the transformation of a 3D porous graphene sheet from a commercial Kapton film. Cross-sectional SEM images verify the vertical connections. The specific capacity of 581 mAh g-1 is maintained until the end, with 99% coulombic efficiency at 0.1C. This simple manufacturing method paves the pathway for future LIG-based, cost-effective, lightweight, mass-producible, long-lasting, vertically conductive electrodes for lithium-ion batteries.

Multilayer Ti3C2Tx-loaded CoOHF composite structures for high-performance lithium-ion batteries

Research into new composites to enhance the performance of lithium-ion battery electrode materials has become a trendy area of study. Cobalt-based composites are particularly prominent due to their exceptional electrochemical performance and unique physicochemical properties. Additionally, Ti3C2Tx MXenes materials are anticipated to replace graphene and other carbonaceous materials since they possess an open structure and low lithium-ion diffusion barrier. In this work, we employed simple hydrothermal method to combine layered Ti3C2Tx with needle-shaped CoOHF. The resulting nanosheets showed an even dispersion of CoOHF in the surface, leading to a remarkable increase in specific capacity. Furthermore, Ti3C2Tx provided a higher number of lithium-ion active sites and improved the lithium-ion migration rate, while also ensuring the structure and stability of CoOHF. This composite material enables stable cycling for 1000 cycles at high current densities of 2 A g−1 and ultimately shows a large capacity of 802.4 mAh g−1 stably. Additionally, CoOHF/MXene composites display exceptional performance rate and cycling stability. This study highlights new feasible strategies for using multilayer Ti3C2Tx in lithium-ion batteries, along with metal hydroxyfluorides in new, highly efficient lithium-ion battery anode materials.

Interconnected Multifunctional Waterborne Polyurethane Binder for Structural Robustness of Si Anodes in Lithium-Ion Batteries

Interconnected Multifunctional Waterborne Polyurethane Binder for Structural Robustness of Si Anodes in Lithium-Ion Batteries

Si anode with high initial Coulombic efficiency, long cycle life, and superior rate capability by integrated utilization of graphene and pitch-based carbon

A variety of strategies have been developed to enhance the cycling stability of Si-based anodes in lithium-ion batteries. Although significant progress has been made in enhancing the cycling stability of Si-based anodes, the low initial Coulombic efficiency (ICE) remains a significant challenge to their commercial application. Herein, pitch-based carbon (C) coated Si nanoparticles (NPs) were wrapped by graphene (G) to obtain Si@C/G composite with a small specific surface area of 11.3 m2 g−1, resulting in a high ICE of 91.2% at 500 mA g−1. Moreover, the integrated utilization of graphene and soft carbon derived from the low-cost petroleum pitch strongly promotes the electrical conductivity, structure stability, and reaction kinetics of Si NPs. Consequently, the synthesized Si@C/G with a Si loading of 54.7% delivers large reversible capacity (1191 mAh g−1 at 500 mA g−1), long cycle life over 200 cycles (a capacity retention of 87.1%), and superior rate capability (952 mAh g−1 at 1500 mA g−1). When coupled with a homemade LiNi0.8Co0.1Mn0.1O2 (NCM811) cathode in a full cell, it exhibits a promising cycling stability for 200 cycles. This work presents an innovative approach for the manufacture of Si-based anode materials with commercial application.

Polyaniline-coated flower-like iron oxide served as anode material for superior-performance lithium-ion batteries

Transition metal oxides applied in anode for lithium-ion batteries are susceptible to particle aggregation during the cycling test, resulting in a low capacity retention during cycling process. In this study, Fe2O3/polyaniline microflowers were prepared via a simple liquid-phase oxidation and calcination process followed by polyaniline coating. Several characterization techniques demonstrated their morphology and chemical composition. When applied in anode for lithium-ion batteries, Fe2O3/polyaniline microflowers exhibit an ultrahigh specific capacity of 1847.1 mAh g−1 over 100 cycles at 0.1 A/g. A high specific capacity of 619.8 mAh g−1 was achieved after 300 cycles at 1.0 A/g. The high performance is mainly due to the polyaniline coating and flower-like microstructures, which can mitigate the volume change, improve the electrical conductivity and cycling stability, and contribute to the rapid Li+ diffusion. This work provides a new route for synthesizing advanced-performance Fe2O3-based anode material.

Exploring silicon nanoparticles and nanographite-based anodes for lithium-ion batteries

This study investigates the performance of silicon nanoparticles (Si NPs) and silicon nanographite (SiNG) composite-based anodes for lithium-ion batteries (LiBs). Si offers a promising alternative to traditional graphite anodes due to its higher theoretical capacity, despite encountering challenges such as volume expansion, pulverization, and the formation of a solid electrolyte interface (SEI) during lithiation. SiNPs anode exhibited initial specific capacities of 1568.9 mAh/g, decreasing to 1137.6 mAh/g after 100th cycles, with stable Li–Si alloy phases and high Coulombic efficiency (100.48%). It also showed good rate capability, retaining 1191.3 mAh/g at 8400 mA g−1 (2.82C), attributed to its carbon matrix structure. EIS indicated charge transfer with RB of 3.9 Ω/cm−2 and RCT of 11.4 Ω/cm−2. Contrastingly, SiNG composite anode had an initial capacity of 1780.7 mAh/g, decreasing to 1297.5 mAh/g after 100 cycles. Its composite structure provided cycling stability, with relatively stable capacities after 50 cycles. It exhibited good rate capability (1191.3 mAh/g at 8399.9 mA g−1), attributed to its carbon matrix structure. Electrochemical impedance spectroscopy showed higher resistances for RB of 4.2 Ω/cm−2 and RCT of 15.6 Ω/cm−2 compared to SiNPs anode. These findings suggest avenues for improving energy storage devices by selecting and designing suitable anode materials.

Insight into graphene/boron arsenide heterostructure used for high-performance lithium-ion battery anode materials: The first principles study

Two-dimensional (2D) van der Waals (vdW) heterostructures demonstrate potential applications in Lithium-ion batteries (LIBs) characterized by their elevated energy storage capacity and extended operational longevity as anode materials. The structures and electronic properties of graphene/boron arsenide (Gr/BAs) heterostructures, along with the adsorption and migration of lithium (Li) atoms within the structures, are methodically analyzed through first-principles studies underpinned by density functional theory. Our calculations indicate the metallic Gr/BAs heterostructures have the structural stability, where their mechanical strength is confirmed from the elastic constant. Its diffusion barrier of Li atoms (0.25 eV) is superior among similar anode materials. The Li atoms' diffusion coefficient within the Gr/BAs heterostructure at 300 K (1.27 × 10−10 m2/s) exceeds that observed in Gr (2.0×10−11 m2/s). Besides, the presence of Gr assists in maintaining the open-circuit voltage (OCV) of Gr/BAs heterostructures in the range of 0-1 V. The theoretical specific capacity of proposed heterostructure reaches 920 mAh/g. The present calculations suggest that the Gr/BAs heterostructure could serve effectively as an anode in LIBs due to its excellent electrical conductivity, small diffusion barriers and appropriate open-circuit voltage.

A novel embedded KVO3/NC anode for high-performance lithium-ion batteries

Vanadium-based metallic salts, characterized by their intrinsic low electronic conductivity, are impeding their advancement as anode materials in the realm of lithium-ion battery technology. This study presents a novel embedded anode material KVO3/NC (KVO/NC) synthesized via a sol–gel method, with KVO3 (KVO) particles in situ growing on N-doped carbon, thereby ameliorating conductivity and electrochemical performance. The findings reveal that KVO/NC composite has three lithium-ion storage sites, ultra-high cycling stability (289 mA h/g@5000 cycles@10 C@100 %), and superior rate performance (249 mA h/g@15 C; 221 mA h/g@20 C). Coupled with LiFePO4 cathode, it achieves a competitive energy density (391 W h kg−1@0.1 C; 1–3.9 V). This work reveals the practical potential of KVO/NC as a new type of lithium-ion battery anode material with high energy density and long cycle life through a series of ex situ/in situ characterizations.

Synthesis and characterization of crystalline cristobalite alpha low silicon dioxide nanoparticles: a cost-effective anode for lithium-ion battery

Silicon dioxide (SiO2 or Silica) is one of the most prevalent substances in the crust of the Earth. The main varieties of crystalline silica are quartz, cristobalite, and tridymite. When applied as a material for energy, it is affordable and eco-friendly. The SiO2 is considered as electrochemically inactive toward lithium. The SiO2 exhibits low activity for diffusion and inadequate electrical conductivity. As the particle size of SiO2 decreases, the diffusion pathway of Li-ions shortens, and the electrochemical activity is promoted. In investigation, Cost-effective synthesis approach was employed to produce crystalline cristobalite alpha low silicon dioxide nanoparticles (CCαL SiO2 NPs) derived from Oryza sativa (rice) husk using a solvent extraction modification technique. The objective was to fabricate an cost-effective future anode nanomaterial that could reduce the significant volume expansion growth, pulverization, and increase electrical conductivity of CCαL SiO2 NPs anode and develop high specific capacity for Lithium-ion battery (LiB). To study the phase and purity of the SiO2, a variety of characterization methods, including X-Ray Diffraction, Fourier Infra-Red Spectroscopy, Surface area analysis, Raman Shift analysis, Field Emission Scanning Electron Microscopy and Energy Dispersive X-Ray Spectroscopy, Contact angle measurement, Post-mortem X-ray diffraction, and Post-mortem field emission scanning electron microscopy were employed. This cost-effective synthesis of CCαL SiO2 NPs anode was first reported in this work.

Modulating porous silicon-carbon anode stability: Carbon/silicon carbide semipermeable layer mitigates silicon-fluorine reaction and enhances lithium-ion transport

Silicon-based material is regarded as one of the most promising anodes for next-generation high-performance lithium-ion batteries (LIBs) due to its high theoretical capacity and low cost. Harnessing silicon carbide's robustness, we designed a novel porous silicon with a sandwich structure of carbon/silicon carbide/Ag-modified porous silicon (Ag-PSi@SiC@C). Different from the conventional SiC interface characterized by a frail connection, a robust dual covalent bond configuration, dependent on SiC and SiOC, has been successfully established. Moreover, the innovative sandwich structure effectively reduces detrimental side reactions on the surface, eases volume expansion, and bolsters the structural integrity of the silicon anode. The incorporation of silver nanoparticles contributes to an improvement in overall electron transport capacity and enhances the kinetics of the overall reaction. Consequently, the Ag-PSi@SiC@C electrode, benefiting from the aforementioned advantages, demonstrates a notably elevated lithium-ion mobility (2.4 * 10−9 cm2·s−1), surpassing that of silicon (5.1 * 10−12 cm2·s−1). The half-cell featuring Ag-PSi@SiC@C as the anode demonstrated robust rate cycling stability at 2.0 A/g, maintaining a capacity of 1321.7 mAh/g, and after 200 cycles, it retained 962.6 mAh/g. Additionally, the full-cell, featuring an Ag-PSi@SiC@C anode and a LiFePO4 (LFP) cathode, exhibits outstanding longevity. Hence, the proposed approach has the potential to unearth novel avenues for the extended exploration of high-performance silicon-carbon anodes for LIBs.

Fundamental Understanding of the Low Initial Coulombic Efficiency in SiOx Anode for Lithium-Ion Batteries: Mechanisms and Solutions.

To meet the ever-increasing demand for high-energy lithium-ion batteries (LIBs), it is imperative to develop next-generation anode materials. Compared to conventional carbon-based anodes, Si-based materials are promising due to their high theoretical capacity and reasonable cost. SiOx, as a Si-derivative anode candidate, is particularly encouraging for its durable cycling life, the practical application of which is, however, severely hindered by low initial Coulombic efficiency (ICE) that leads to continuous lithium consumption. What is worse, low ICE also easily triggers a terrible chain reaction causing bad cycling stability. To further develop SiOx anode, researchers have obtained in-depth understandings regarding its working/failing mechanisms so as to further propose effective remedies for low ICE mitigation. In this sense, herein recent studies investigating the possible causes that fundamentally result in low ICE of SiOx, based on which a variety of solutions addressing the low ICE issue are discussed and summarized, are timely summarized. This perspective provides valuable insights into the rational design of high ICE SiOx anodes and paves the way toward industrial application of SiOx as the next generation LIB anode.

A facile electrospinning strategy to prepare cost-effective carbon fibers as a self-supporting anode for lithium-ion batteries

Carbon materials with fibrous morphology and enhanced mechanical properties have shown to be promising materials as self-supporting anode materials for lithium-ion batteries (LIBs). In this study, coal-based carbon fibers (CFs) with favorable flexibility and superior tensile strength were prepared from lignite and coal derivatives such as coal-based humic acid and coal tar pitch via electrospinning in the assistance of polyacrylonitrile. All these coal-based CFs have an 1D dense fibrous microstructure with controllable diameter and appreciable specific surface area with enriched in O/N-containing groups by rationally choosing the precursor type. The organic macromolecules enriched aromatic ring in lignite and coal derivatives cross-link with linear polyacrylonitrile molecular chains to form a more solid three-dimensional (3D) network framework under the conditions of electrospinning and carbonization. Such 3D microstructure not only can significantly improve the flexibility and tensile strength of coal-based CFs, but also can increase the content of graphite-like microcrystalline carbon (sp2 carbon) in carbon fibers, thereby improving the electrical conductivity. Due to the smaller molecular structure, coal tar pitch can be more easily combined with polyacrylonitrile by electrostatic force. The CFs derived from coal tar pitch (CTP-CFs) exhibited the largest average diameter (156.2 nm), a higher microporous surface area (2.6 m2·g−1), higher pyrrole nitrogen and contained reasonable proportions of amorphous carbon (sp3 carbon) and sp2 carbon. As a consequence, among the various derived coal-based CFs applied as self-supporting anode materials for LIBs, CTP-CFs showed the highest first reversible capacity (770.8 mAh·g−1 at 20 mA·g−1) and excellent cycling performance with capacity retention rate of 89.1 % after 200 cycles. This work paves a new strategy to prepare CFs as flexible self-supporting anodes for LIBs from low-cost carbon precursors that can be rationally chosen to further tune the property of the CFs.