Anode For Li-ion Batteries Research Articles

High Capacity NbS2-Based Anodes for Li-Ion Batteries.

We have investigated the lithium capacity of the 2H phase of niobium sulfide (NbS2) using density functional theory calculations and experiments. Theoretically, this material is found to allow the intercalation of a double layer of Li in between each NbS2 layer when in equilibrium with metal Li. The resulting specific capacity (340.8 mAh/g for the pristine material, 681.6 mAh/g for oxidized material) can reach more than double the specific capacity of graphite anodes. The presence of various defects leads to an even higher capacity with a partially reversible conversion of the material, indicating that the performance of the anodes is robust with respect to the presence of defects. Experiments in battery prototypes with NbS2-based anodes find a first specific capacity of about 1,130 mAh/g, exceeding the theoretical predictions.

Mechanically Exfoliated Graphite for Highly Reversible Na-Storage with Carbon Coated Na3V2(PO4)3 Cathode with Low-Temperature Conditions.

Tremendous efforts are put forward to develop novel high-performance electrodes for Na-ion batteries (SIBs) in order to replace commercial Li-ion batteries (LIBs). Graphite, the most versatile anode for LIBs, fails to accommodate Na+ions owing to the poor thermodynamic stability of the binary graphite intercalation compound. This study aims to exfoliate the layers of graphite through a simple mechanical process at different time intervals (1, 5, 10, 20, 40, and 80h) and examine the potential candidate for Na-storage in the presence of carbonate-based electrolytes. This study reports that ball milling plays a vital role in the performance of the graphite in Na-storage. The graphite exfoliated for 80h (EG-80h) rendered an excellent reversible capacity of 209mAhg-1 with coulombic efficiency of >99% after 100 cycles in EC-based electrolyte. In situ impedance analysis is performed to validate the charge storage mechanism and Na-ion kinetics. The performance of EG-80h in a full-cell assembly is evaluated with a carbon-coated Na3V2(PO4)3 cathode, which exhibited an initial capacity of ≈75mAhg-1 andenergy density of 201Whkg-1. In addition, the adaptability of the NVPC/EG-80h cell at different temperatures is examined from -10 to 50°C, displaying excellent performance in both high and low-temperature conditions.

DFT study of lithium adsorption on silicon quantum dots for battery applications

Understanding lithium (Li) adsorption in silicon quantum dots (SiQDs) is crucial for optimizing Li-ion battery (LIB) anode materials. We systematically investigated Li adsorption in ten hydrogenated SiQDs (Si10H16, Si14H20, Si18H24, Si22H28, Si26H30, Si30H34, Si35H36, Si39H40, Si44H42, and Si48H46) across five adsorption sites (bridge(B), on-top(T), hollow-tetrahedral inner(Tdinner), hollow-tetrahedral surface(Tdsurface), and hollow-hexagonal(Hex)), utilizing density functional theory (DFT) with the M06–2X hybrid functional and 6-31G+(d) basis set. Findings identify Tdinner as the most favorable adsorption site, with a binding energy (Ebind) of 0.80–1.00 eV, dependent on SiQD size. The adsorption site exerts a more pronounced impact on Ebind than the cluster size. Multiple adsorptions in SiQDs show increased Ebind per Li atom with Li atom number. Molecular volume changes, independent of Li atom number but site-dependent, exhibit a maximum of 2.51 %. SiQD energy gap, influencing conductivity, varies with size, larger SiQDs being more conductive, especially with Li adsorption. Conclusively, our study recommends large-sized SiQDs as optimal LIB anode materials, offering high capacity, minimal volume expansion, and reasonable conductivity. This research addresses a theoretical gap, illuminating the impact of Li adsorption on SiQD molecular volumes and electronic structures, aiding in the design of enhanced capacity silicon anodes for LIB.

Cation ordering in low-temperature niobium-rich NbWO bronzes: New anodes for high-rate Li-ion batteries

Cation ordering in low-temperature niobium-rich NbWO bronzes: New anodes for high-rate Li-ion batteries

Developing an Efficient Anode for Li-Ion Batteries Based on Vertically-Aligned CNTs Decorated with Sn-Ni Alloy

Developing an Efficient Anode for Li-Ion Batteries Based on Vertically-Aligned CNTs Decorated with Sn-Ni Alloy

Post-mortem study and long cycling stability of silica/carbon composite as anode in Li-ion cells

The present work emphases on the post-mortem study of silica/carbon composite as functional anode in Li-ion batteries (LIBs). Herein, the silica/carbon composite is synthesized by facile in-situ hydrothermal technique. The x-ray diffraction (XRD) pattern indicates the amorphous nature of silica/carbon composite. The stacked sheet-like morphology of silica/carbon composite is seen in the high-resolution transmission electron microscopy (HR-TEM) & scanning electron microscopy (SEM) images. In addition, Raman spectroscopy, Fourier transform infrared (FTIR) spectroscopy, energy dispersive x-ray analysis (EDAX), and x-ray photoelectron spectra (XPS) characterizations of silica/carbon composite has been studied in detail. The rate capability of silica/carbon composite anode in LIB indicates 99% capacity retention after applying current density ranging from 50 mA g−1 to 1000 mA g−1, successively. The composite anode delivers a stable specific capacity ∼300 mAh g−1 at a current density of 100 mA g−1 for 500 cycles. Electrochemical impedance spectroscopy (EIS) study analyzed the faster Li-ion diffusion and increment in the diffusion coefficient by a factor of 1000 after 500 cycles. To the best of our knowledge, this is the first work on the post-mortem study of silica/carbon composite as anode in LIB. Post-cycling characterizations including XRD, FTIR, and SEM reveal the absence of any impurity phases and negligible volumetric expansion after prolonged cycling. It further confirms that the carbon present in the silica/carbon composite helps to accommodate the volumetric expansion of silica and prevents cracking of the anode over 500 cycles.

Stabilizing Zn2SiO4 Anode by a Lithium Polyacrylate Binder for Highly Reversible Lithium-Ion Storage.

Binders are crucial for maintaining the mechanical stability of the electrodes. However, traditional binders fail to adequately buffer the volume expansion of Zn2SiO4 anode, causing electrode contact failure and considerable capacity loss during cycling. In this study, we propose a simple and effective solution to address these challenges through a combined strategy of hollow structure design and the introduction of an aqueous lithium poly(acrylic acid) (LiPAA) binder. Hollow structures can shorten ion-transfer distance and accommodate volume change outside. The excellent adhesion of the LiPAA binder created a secure connection between the active Zn2SiO4 particles, conductive additives, and the current collector, which enhanced the mechanical stability and integrity of the electrode. As a result of these positive factors, a Zn2SiO4 electrode using LiPAA as a binder can deliver an excellent capacity of 499 mAh g-1 at a high current density of 5 A g-1 and a long life span of 1000 cycles at 1 A g-1 with a capacity retention of 98%, which significantly outperforms other binders. As demonstrated by ex situ X-ray diffraction and ex situ X-ray absorption spectroscopy, the storage of lithium ions in Zn2SiO4 follows a dual conversion-alloying mechanism, using Zn as the redox center. In this process, Zn is first reduced to metallic Zn and then forms a LiZn alloy upon lithium-ion insertion. This work shows that LiPAA offers a promising approach to improve the cycling longevity of conversion and alloying anodes in Li-ion batteries.

Purification of Spherical Graphite as Anode for Li-Ion Battery: A Comparative Study on the Purifying Approaches.

Graphite is a versatile material used in various fields, particularly in the power source manufacturing industry. Nowadays, graphite holds a unique position in materials for anode electrodes in lithium-ion batteries. With a carbon content of over 99% being a requirement for graphite to serve as an electrode material, the graphite refinement process plays a pivotal role in the research and development of anode materials for lithium-ion batteries. This study used three different processes to purify spherical graphite through wet chemical methods. The spherical graphite after the purification processes was analysed for carbon content by using energy-dispersive X-ray (EDX) spectroscopy and was evaluated for structural and morphological characteristics through X-ray diffraction (XRD), scanning electron microscopy (SEM), and Brunauer-Emmett-Teller (BET) analyses. The analyses results indicate that the three-step process via H2SO4-NaOH-HCl cleaning can elevate the carbon content from 90% to above 99.9% while still maintaining the graphite structure and spherical morphology, thus enhancing the surface area of the material for anode application. Furthermore, the spherical graphite was studied for electrochemical properties when used as an anode for Li-ion batteries using cyclic voltammetry (CV) and galvanostatic charge-discharge (GCD) measurements. The results demonstrated that the purification process significantly improves the material's capacity with a specific capacity of 350 mAh/g compared to the 280 mAh/g capacity of the anode made of spherical graphite without purification.

Efficient synthesis and lithium storage performance of SiO2/TiO2 composite film anode by plasma electrolytic oxidation

SiO2/TiO2 composite films with different phase ratios have been successfully fabricated via the one-step plasma electrolytic oxidation (PEO) method in an alkaline electrolyte on Ti foil to obtain a binder-free anode for Li-ion batteries. The formed composite films present porous morphology of TiO2 with a uniform distribution of SiO2. The specific capacity can stabilize above 400 mAh/g at the current density of 100 μA cm−2 for 500 cycles, together with the apparent improved initial coulombic efficiency of 88.7 % and excellent rate capability, which arises from the peculiar structure and the synergic enhancement effect of SiO2 active materials and TiO2 matrix. This work provides an efficient and low-cost route for the preparation of Li-ion battery binder-free anodes and enriches the application of plasma electrolysis technology in energy field.

Nb2C and Nb2CO2 MXenes as Anodes in Li-Ion Batteries: A Comparative Study by First-Principles Calculations.

The new generation of Li-ion batteries is based on integrating 2D materials into the electrodes to increase the energy density while reducing the charging time and size. The two-dimensional transition metal carbide or nitride (MXene) materials offer ideal electronic properties, such as metallic behavior, low energy barriers for Li-ion diffusion, and structural stability. This study focuses on Nb2C and Nb2CO2 MXenes, which have shown promising Li-storage capacity, especially the oxidized phase. By using density functional theory (DFT) and thermodynamic criteria, we studied the Li intercalation process in both MXenes. The results show that the Li intercalation process in the oxidized phase is more stable. Also, the Li diffusion barriers are 35 and 250 meV for the bare and oxidized phase, due to the strong interaction between Li ions and O functional groups. Nb2C and Nb2CO2 MXenes deliver a maximum gravimetric theoretical capacity of 275 and 233.26 mA h/g, respectively, with a stable performance.

N-Containing Porous Carbon-Based MnO Composites as Anode with High Capacity and Stability for Lithium-Ion Batteries.

MnO has attracted much attention as the anode for Li-ion batteries (LIBs) owing to its high specific capacity. However, the low conductivity limited its large application. An effective solution to solve this problem is carbon coating. Biomass carbon materials have aroused much interest for being low-cost and rich in functional groups and hetero atoms. This work designs porous N-containing MnO composites based on the chemical-activated tremella using a self-templated method. The tremella, after activation, could offer more active sites for carbon to coordinate with the Mn ions. And the as-prepared composites could also inherit the special porous nanostructures of the tremella, which is beneficial for Li+ transfer. Moreover, the pyrrolic/pyridinic N from the tremella can further improve the conductivity and the electrolyte wettability of the composites. Finally, the composites show a high reversible specific capacity of 1000 mAh g-1 with 98% capacity retention after 200 cycles at 100 mA g-1. They also displayed excellent long-cycle performance with 99% capacity retention (relative to the capacity second cycle) after long 1000 cycles under high current density, which is higher than in most reported transition metal oxide anodes. Above all, this study put forward an efficient and convenient strategy based on the low-cost biomass to construct N-containing porous composite anodes with a fast Li+ diffusion rate, high electronic conductivity, and outstanding structure stability.

Amorphous GeSnSe nanoparticles as a Li-Ion battery anode with High-Capacity and long cycle performance

A new ternary amorphous GeSnSe (GSS) nanopowder was effectively synthesized by using ball milling under inert atmosphere. Its topographical, microstructural and elemental characterizations revealed the formation of nanoparticles with undefined shape, short-range order and the tailored stoichiometry. Remarkably, this novel amorphous material demonstrates its competences as a promising Li-ion host anode, exhibiting a high cycle performance with a specific charge capacity of 963 mAh g−1 at an applied C-rate of 0.2C with a coulombic efficiency > 99.4 % after 300 cycles. Its high specific capacity, large rate capability, acceptable capacity retention and long cycle life could be attributed to a dual Li-ion storage mechanism that consists mostly of multiple reversible electrochemical processes as conversion and alloying reactions and capacitive processes. Moreover, its stable volume expansion (34 %), moderate electrode polarization (248.9 mV), reasonable charge transfer resistance (83 Ω) and apparent Li-ion diffusion coefficients between 10–9 – 10–14 cm2 s−1 could be promoted by a synergistic effect between Ge (capacity), Sn (conductivity) and Se (stability), which plays an important role on the stability and high cycle performance of the promising GSS-based anode.

Controlled morphology significantly enhances electrochemical performance of LaNiO3-NiO anodes for Li-ion batteries

Traditional graphite anodes have become increasingly reliable in lithium-ion battery applications. However, there is an urgent need to overcome their limitations, such as the low theoretical capacity and less favorable rate performance. Recently, perovskite-type oxides have garnered increasing attentions as anodes owing to their advantages of capacity, rate performance, lifespan, and safety. In our previous study, the electrochemical performance of LaNiO3-NiO nanoparticles was enhanced compared to those of LaNiO3, primarily thanks to the synergistic effect of the biscuit-shaped LaNiO3-NiO and graphene-like layered g-C3N4. Morphology modulation is an important method for enhancing the performance of the anode materials. Based on this concept, we designed two kinds of LaNiO3-NiO with different morphologies (micro-sphere and micro-flower), and tested their physical and electrochemical properties. The discharge capacity of the LaNiO3-NiO micro-sphere anode was 714.5 mAh g−1 after 950 cycles at 1000 mA g−1, which is significantly higher than those of LaNiO3-NiO micro-flower and nanoparticle. However, the LaNiO3-NiO Micro-flower anode maintains a reversible capacity of 144.2 mAh g−1 at 10.0 A g−1, which is higher than that of the LaNiO3-NiO Micro-sphere electrode (125.8 mAh g−1). It was found that the morphology modification endows the electrodes possessing their own outstanding electrochemical properties.

Enhanced Li storage of pure crystalline-C60 and TiNb2O7-nanostructure composite for Li-ion battery anodes

We propose a method for producing composite materials (hTNO@C60) comprising crystalline C60 particles and hollow-structured TiNb2O7 (hTNO) nanofibers via facile liquid–liquid interface precipitation followed by low-temperature annealing. This allows the systematic design of crystalline C60 as an active material for Li-ion battery anodes. The hTNO@C60 composite demonstrates outstanding cyclic stability, retaining a capacity of 465 mA h g−1 after 1,000 cycles at 1 A g−1. It maintains a capacity of 98 mA h g−1 even after 16,000 ultralong cycles at 8 A g−1. The enhancement in electrochemical properties is attributed to the successful growth and uniform doping of crystalline C60, resulting in improved electrical conductivity. The excellent electrochemical stability and properties of these composites make them promising anode materials.

Enhanced electrochemical performance of MgFeO4 spinel as anode materials for Lithium-ion batteries through manganese doping

Existing graphite anode materials are reaching their limits, and iron-based AB2O4 spinel materials are considered as potential anodes for Li-ion batteries owing to their significant theoretical capacities. In this work, novel nanocrystalline MgFe2-xMnxO4 (x = 0, 0.1, 0.2, and 0.3) spinel ferrites were evaluated as anode materials for high-capacity Li-ion batteries. The Mn-doped MgFe2-xMnxO4 (x = 0, 0.1, 0.2, and 0.3) spinel ferrites were synthesized through a facile sol-gel synthesis method coupled with an annealing process. Their crystal structure, morphology, and purity were examined via X-ray diffraction (XRD), Raman spectroscopy, and scanning electron microscopy (SEM). The X-ray diffraction analyses with Rietveld refinement of the synthesized ferrites reveal pure cubic structure with a characteristic Fd3̅m space group for all prepared samples. This was confirmed by Raman spectroscopy by revealing five spinel Raman active modes. The SEM images showed interconnected nanosized particles for all compositions, which led to a porous morphology. Their electrochemical proprieties as anode materials for Li-ion batteries were examined by cyclic voltammetry and galvanostatic charge-discharge tests. For all compositions, the cyclic voltammetry plots demonstrate the conversion type for the Li-ion storage mechanism. At an applied current density of 150 mA g−1, the compositions x = 0, 0.1, 0.2, and 0.3 show initial discharge/charge capacities of 1235/712, 1187/680, 1542/938, and 1239/768 mAh g−1, respectively. After 100 operational cycles, their galvanostatic charge/discharge capacities remain 529/534, 612/606, 642/663, and 700/700 mAh g−1. However, the compositions x = 0.2 and 0.3 exhibit excellent cycling stability during 100 cycles, even at higher rates. As a result, the Mn doping led to enhanced specific capacity and cycling stability of the MgFe2O4 spinel. The optimized compositions with x = 0.2 and 0.3 are, thus, proposed as promising anodes materials compositions for Li-ion batteries.

Impacts of radiation sources on structures and electrochemical performance of SiO2/C composite anodes for Li-ion batteries

Application of radiation with highly energetic electrons and ions can be an alternative method to modify structures of crystalline materials. This radiation can potentially induce phase transformations while preserving some physical characteristics and morphology of the materials, hence impacting their useful properties. Here, we report the impacts of e-beam and gamma radiation on the structures and electrochemical performance of SiO2/C anodes for Li-ion batteries (LIB) obtained from rice husk ash (RHA). The effects of radiation sources on structural and physical properties are investigated using X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), X-ray fluorescence spectrometry (XRF), electron microscopy, and Raman spectroscopy. After irradiation-induced processes using e-beam and gamma radiation at 1000 kGy, the mean diameters of the SiO2 particles were around 30 ± 10 and 27 ± 10 nm, respectively, while retaining their round-shaped particle morphology. Both radiation sources induce formation of disordered carbon structure as indicated by the higher ID/IG Raman peaks ratios than the pristine sample. Electrochemical properties were studied using half-coin type cells. The modified structure of SiO2/C anodes caused by irradiation showed improved electrochemical performance, compared with pristine material.

Polyaniline layered N-doped carbon-coated iron oxide nanocapsules for extremely active Li-ion battery anode and oxygen evolution reaction

We report the effective synthesis of polyaniline (PANi)-layered nitrogen-doped carbon-coated Fe3O4 (FNC@PANi) nanocapsules (NCs) for electrocatalysis of oxygen evolution reaction (OER) as well as anode material for lithium (Li)-ion batteries (LIBs) via a simple hydrothermal method and oxidative polymerization technique. The prepared FNC@PANi NCs revealed a dual core-shell structure, in which an intermediate carbon layer allowed excellent electrical conduction between the Fe3O4 NCs and PANi. The dual core-shell structure also allowed the Fe3O4 NCs to expand freely during the Li-ion insertion/extraction and OER processes without breaking the outer layer, thus providing a high surface area (147.85 m2 g−1) and enhanced electrical conductivity. These properties facilitate the application of the dual core-shell FNC@PANi NCs as an advanced electrode material for LIBs, delivering a high reversible specific capacity of 1556.48 mAh g−1 at 0.1 A g−1, excellent rate performance (896.96 mAh g−1 at 1 A g−1), and durable cycling life (680.12 mAh g−1 at 5 A g−1 for 3000 cycles). The dual core-shell FNC@PANi NCs exhibited high electrocatalytic activity in the OER, with a small Tafel slope of 108.7 mV dec−1 owing to synergistic effects between the copious active sites of the Fe3O4 NCs and the carbon core-shell structure and a modest overpotential of 219 mV at 10 mA cm−2. The electrodes showed excellent stability over 10 h, as determined by chronopotentiometry at 10 mA cm−1. The resultant dual-core-shell FNC@PANi NCs are efficient iron-oxide-based electrode materials for LIBs and OER electrocatalysts.

Carbon coated and oxygen vacancies incorporated Wadsley-Roth phase molybdenum niobium oxide for high-performance lithium-ion storage

Nb-based oxides with Wadsley-Roth shear structure have been aroused extensive research interest as promising anode for Li-ion batteries, due to the multi-electron redox, safe working voltage and open structural framework. However, the low intrinsic electronic conductivity limits their further practical applications. Herein, the lithium storage performances of MoNb6O18 with Wadsley-Roth shear structure are optimized by carbon coating and oxygen vacancies (VO-MNO@C), which synthesized with freeze-drying and subsequently heat treatment. As expected, the VO-MNO@C electrode demonstrates a high initial reversible capacity of 259.6 mAh/g at 0.2C and the capacity retention rate of 85.7 % after 200 cycles at 1C. Moreover, the reversible of Mo6+/Mo5+ and Mo5+/Mo4+ redox reaction can be effectively improved. In situ X-ray diffraction (XRD) and ex situ X-ray photoelectron spectroscopy (XPS) characterization indicate that VO-MNO@C undergoes a solid-solution structural evolution disclosing the stepwise reaction of Mo5+/Mo6+, Mo4+/Mo5+, Nb4+/Nb5+ and Nb3+/Nb4+ redox couples with a small volume variation of 5.7 %. Also, the full cell based on commercial LiMn2O4 cathode and VO-MNO@C anode displays an operating voltage about 2.4 V with the high energy density of 681.4 Wh/kg (calculated with the mass of anode). This work will offer more insights for the development of Wadsley-Roth shear structure anode materials with excellent Li-ion storage properties.

Recycling of waste silicon powder from the photovoltaic industry into high performance porous Si@void@carbon anodes for Li-ion battery

To enhance the performance of lithium-ion battery anodes, this study leverages recycled diamond wire-cut silicon particles, a byproduct of the photovoltaic sector. These particles undergo purification through acid wash and pyrolysis to eliminate contaminants, thereby serving as potential anode materials. The inherent challenge with silicon involves its significant volumetric expansion during lithiation and delithiation, which hampers its viability for commercial applications. Addressing this, the research introduces a facile approach by synthesizing porous silicon (pSi) via the Ag-assisted chemical etching method. Subsequently, a distinctive yolk-shell porous silicon@void@carbon (pSi@V@C) structure is created using a sacrificial template approach, ensuring the formation of voids between the porous silicon core and the carbon shell. This configuration mitigates the detrimental effects of silicon's volume expansion while enhancing electrical conductivity through the carbon shell. The pSi@V@C composite exhibits promising electrochemical performance, demonstrated by an initial discharge capacity of 1826 mAh g-1 and a Coulombic efficiency of 68.6% at 0.1 A g-1. Remarkably, it maintains a capacity of 821.8 mAh g-1 after 550 cycles at 1 A g-1, with a retention rate of 90.4%.

Core Shell Structured Silica/Porous Carbon Composite as an Efficient Anode for Lithium Ion Batteries

Si‐based materials are taken into consideration as suitable anode materials for lithium‐ion (Li‐ion) batteries due to their high specific capacity. However, their cycle life is limited due to high volumetric changes during discharging and charging in Li‐ion battery (LIB). Silica (SiO2) is abundantly present in nature, but standalone delivers moderate Li storage capacity. Commercially, graphite is considered as efficient anode in LIB. The current research focuses on improving the performance of silica as anode material to achieve the best specific capacity of LIBs. Herein, the core‐shell‐structured silica/porous carbon composite (50:50, wt%) is synthesized using a hydrothermal method. The shell of porous carbon not only covers the core silica but also provides a very high surface area of ≈1057 m2 g−1 to the composite. The synthesized silica/porous carbon composite acts as an active anode material in Li‐ion half‐cell, which shows the best specific capacity of ≈642 mAh g−1 at 700 cycles at 100 mA g−1 current density and a high capacity retention of ≈97%. The porous carbon on silica helps in the uniform percolation of the electrolyte. It also provides a conducting path to the electrons and further reduces Li‐ion diffusion time by producing more active sites. The shell of porous carbon on core‐silica helps to suppress the volumetric changes that happen during the lithiation and de‐lithiation process. Due to these advantages, the core‐shell‐structured silica/porous carbon composite anode shows consistent and stable cycling performance over large number of cycles.