Anode For Na-ion Batteries Research Articles

Optimizing Disorder: Pretreatment Strategies for Saccharide-based Hard Carbon Anodes in Na-ion Batteries

Abstract The need for an alternative to lithium-ion batteries motivates the development of sodium-ion batteries, specifically focusing on biomass-derived hard carbon (HC) as anode material. However, the compositional variability in biomass leads to a lack of correlation between the microstructure and properties of HC. In this study, we used four simple carbohydrates present in all biomass-derived precursors as model objects to establish a reliable relationship between pretreatment temperature, the carbonization mechanism, defectiveness, and the electrochemical characteristics of HCs. The statistical analysis of Raman spectra from 25 HC samples enabled us not only to determine the degree of defectiveness in HCs but also, for the first time, to compare materials based on their inhomogeneity—that is, the variation in defectiveness within each HC material. The initial Coulombic efficiency of hard carbons was improved by 40%, reaching 89%, through the simultaneous reduction of surface area, defectiveness, and inhomogeneity. Additionally, the full cell with the HC and Na3V2(PO4)3/С cathode material demonstrated 80% capacity retention after 300 cycles.

Surface-dominated sodium storage enabled by TiO2 nanosheets with 84 % exposure of (0 0 1) facets for high-performance Na-ion battery anodes

Anatase titanium dioxide (TiO2) has garnered enormous attention as a promising anode material for sodium-ion batteries (SIBs), owing to its non-toxicity, superior structural stability, and cost-effectiveness. Nevertheless, its intrinsic low electrical conductivity poses a substantial challenge to its practical applications. Here, the ultrathin TiO2 nanosheets were obtained. The TiO2 nanosheets with a thickness of ∼8 nm and exposed 84 % (001) facet. The exposed (001) crystal facets and ultrathin nanosheet structure provide abundant active sites for Na-ion adsorption, shortens ion diffusion pathways, enhances reaction kinetics, and significantly boosts the pseudocapacitive effect. This synergistic strategy of exposed (001) facet with nanosheets structure leads to an exceptional capacity of 177.1 mAh/g at 0.1 A/g, and 59 % capacity retention at 5 A/g. This work will contribute to the understanding of facet-dependent electrochemical behavior anode materials for high-performance SIBs.

Two-Dimensional ABS4 (A and B = Zr, Hf, and Ti) as Promising Anode for Li and Na-Ion Batteries.

Metal ion intercalation into van der Waals gaps of layered materials is vital for large-scale electrochemical energy storage. Transition-metal sulfides, ABS4 (where A and B represent Zr, Hf, and Ti as monolayers as anodes), are examined as lithium and sodium ion storage. Our study reveals that these monolayers offer exceptional performance for ion storage. The low diffusion barriers enable efficient lithium bonding and rapid separation while all ABS4 phases remain semiconducting before lithiation and transition to metallic states, ensuring excellent electrical conductivity. Notably, the monolayers demonstrate impressive ion capacities: 1639, 1202, and 1119 mAh/g for Li-ions, and 1093, 801, and 671 mAh/g for Na-ions in ZrTiS4, HfTiS4, and HfZrS4, respectively. Average voltages are 1.16 V, 0.9 V, and 0.94 V for Li-ions and 1.17 V, 1.02 V, and 0.94 V for Na-ions across these materials. Additionally, low migration energy barriers of 0.231 eV, 0.233 eV, and 0.238 eV for Li and 0.135 eV, 0.136 eV, and 0.147 eV for Na make ABS4 monolayers highly attractive for battery applications. These findings underscore the potential of monolayer ABS4 as a superior electrode material, combining high adsorption energy, low diffusion barriers, low voltage, high specific capacity, and outstanding electrical conductivity.

Analysis of interlayer dependency of MoS2/g-C3N4 heterostructure as an anode material for sodium-ion batteries

In this present work, we explore the effectiveness of layered molybdenum disulfide (2H-MoS2) and graphitic carbon nitride (g-C3N4) heterostructure as anode for Sodium-Ion Batteries (SIBs) by using first principles analysis. To study the anode properties, we varied the interlayer distance between 2H-MoS2/g-C3N4 as 3Å, 6Å, 9Å,12 Å, and 14 Å between MoS2 as substrate and g-C3N4 as top layer. The fundamental properties, such as structural stability and electronic structure were analysed for the respective systems. The adsorption kinetics of Na ion on the g-C3N4 layer were analysed by performing molecular dynamics (MD) simulations to understand the adsorption mechanism better. Our results showed that the interlayer distance of 6 Å with formation energy of −4.31 eV, the theoretical specific capacity value of 765.32 mAhg−1, the average electrode potential is between 0.8 and 1.3 V and the adsorption energy of −2.16 eV is suitable for MoS2/g-C3N4 based anodes for Na ion batteries.

First-principles study of Na adsorption and diffusion over substitutionally doped antimonene

The storage of the colossal amount of energy is the eminent research area for the era of eternal need of energy. Sodium-ion (Na-ion) battery emerged as an appropriate alternative to fulfil this. Here, we investigate the functionalities of doped antimonene monolayer (with Ge, Se, Sn and Te atom) as an anode material for Na-ion battery using First-principles Density Functional Theory (DFT) approach. The adsorption and diffusion of Na over the substitutionally doped antimonene is well supported thermodynamically with an adsorption energy of range −2.3 eV to −2.8 eV and minimum activation energy of range 0.1 eV to –0.8 eV. The conductivity of doped antimonene increases with the number of Na atoms adsorbed over it as seen by bandstructure, density of states (DOS) and electron difference density (EDD) plots. Inhomogeneities and structural disturbances were absent during adsorption and diffusion indicating a robust electrode material. The outcomes predict that the doped antimonene monolayer can be a potential candidate for Na-ion battery anode material application.

Functionalized MBene, Ti[formula omitted]BX[formula omitted] (X=Si, Ge, P, As) as potential excellent anode materials for lithium and sodium-ion batteries: A first-principles study

In the search for next-generation energy storage devices, superior-performance alternative electrode materials based on two-dimensional materials for rechargeable metal-ion batteries are essential. Here, we explored group III and IV functionalization of 2D Ti2B, Ti2BX2 (X=Si, Ge, P, As) as anode materials for Li and Na ion batteries using first-principles calculations. The structures had excellent metallic properties and demonstrated energetically favorable adsorptions for metal ions. Analyzing charge transfer and electronic band structures, silicon and phosphorous-functionalized Ti2B (Ti2BSi2 and Ti2BP2) showed the most potential. The energy band diagrams showed that both Ti2BSi2 and Ti2BP2 had metallic characteristics after Li and Na-ion adsorption, which offered considerable advantage for rechargeable-ion batteries. The structures exhibited low energy barriers for Li and Na-ion migration. The minimum energy barriers calculated for Na were 0.08 eV for Ti2BSi2 and 0.24 eV for Ti2BP2. Theoretical specific capacity and open circuit voltage were calculated using maximum layer adsorption. For both Li and Na, high values of specific capacity and low values of open circuit voltage (¡ 1 V) were found. Ti2BSi2 had the best performance, with a theoretical specific capacity of 1647.10 and 1317.68 mA h/g for Li and Na, respectively. Its open circuit voltages for Li and Na were 0.65 and 0.38 V. The insights of this study will be beneficial in fabricating high-performing Ti2BX2-based anodes for rechargeable Li and Na ion batteries.

Sodium into γ-Graphyne Multilayers: An Intercalation Compound for Anodes in Metal-Ion Batteries.

The bulk synthesis of γ-graphyne has been recently achieved and evidenced a multilayered structure, which suggests its potential exploitation as a substitute of graphite-based anode materials for metals heavier than lithium (Li). In fact, each of its regular pores of sub-nanometric size features an optimal environment for hosting a single sodium (Na) ion, as reported here by means of accurate electronic structure calculations. We show that the graphyne/Na ion coupling mimics that found on the graphene/Li ion in terms of metal-single layer interaction and equilibrium distance. More importantly, in contrast to what is found for graphite, we demonstrate that graphyne intercalation compounds with Na are thermodynamically stable and feature an optimal storage capacity of 372 mAh·g-1. These findings, together with a limited crystal structure expansion upon Na intercalation, a low metal diffusion barrier as well as high electrical conductivity, pave the way to the development of novel graphyne-based anodes for efficient Na-ion batteries.

Enhanced Performance for Li & Na Ion Battery Anodes by Charge Modulation of Interface Through SiC4 and SiN1C3 Active Centers on Silicon Nitrogen Co‐Doped Graphene

AbstractHeteroatom doping of graphene is a powerful approach to develop high‐performance Li and Na ion battery anodes. In this study, silicon‐nitrogen co‐doped graphene (Si−N−GN) nanostructures were successfully synthesized via a rational and scalable solvothermal process. The performances of Si−N−GN in Na+ and Li+ half‐cells were investigated in detail by advanced electrochemical techniques and the obtained results were analyzed in terms of Si−N−GN surface properties, reaction kinetics, and electrode/interface interactions. Si−N−GN exhibited a superior capacity of 540 mAh g−1 at a current density of 0.5 A g−1 for Li+ and improved rate capability for both Li+ and Na+ which are linked with the increased interlayer spacing and enlarged graphene sheets upon Si‐doping. Importantly, the capacity increased with the number of cycles owing to surface electron density redistribution and Si−N−GN/SEI interactions, supported by DFT.

Theoretical prediction of two-dimensional metallic AM2B8 (AM = K, Rb, Cs) as anode materials for Na-ion batteries

The development of two-dimensional anode materials with superior performance is becoming a critical undertaking for the advancement of Na-ion battery technology. Using isoelectronic substitution strategies, we predicted three alkali metal borides AM2B8 (AM = K, Rb, Cs) based on the SrB8 monolayer. Ab initio molecular dynamics simulations and phonon dispersion relationship calculations demonstrated their stability. Using density functional theory, we predict the feasibility of these three new metal nanosheets as anodes for Na-ion batteries. The AM2B8 monolayer retains its metallicity after the insertion of Na ions, ensuring that the anode has good electrical conductivity. In addition, AM2B8 has a low diffusion barrier and open circuit voltage (K2B8 is 0.08 eV and 0.26 V) during charge/discharge. In the voltage range that inhibits dendrite growth, K2B8 can reach the maximum theoretical specific capacity (326 mAh/g). These results indicate that AM2B8, especially K2B8, is a promising anode material for Na-ion batteries.

Coupling Liquid Electrochemical TEM and Mass-Spectrometry to Investigate Electrochemical Reactions Occurring in a Na-Ion Battery Anode.

A novel approach for investigating the formation of solid electrolyte interphase (SEI) in Na-ion batteries (NIB) through the coupling of in situ liquid electrochemical transmission electron microscopy (ec-TEM) and gas-chromatography mass-spectrometry (GC/MS) is proposed. To optimize this coupling, experiments are conducted on the sodiation of hard carbon materials (HC) using two setups: in situ ec-TEM holder and ex situ setup. Electrolyte (NP30) is intentionally degraded using cyclic voltammetry (CV), and the recovered liquid product is analyzed using GC/MS. Solid product (µ-chip) is analyzed using TEM techniques in a post-mortem analysis. The ex situ experiments served as a reference to for insertion of Na+ ions in the HC, SEI size (389 nm), SEI composition (P, Na, F, and O), and Na plating. The in situ TEM analysis reveals a cyclability limitation, this issue appears to be caused by the plating of Na in the form of a "foam" structure, resulting from the gas release during the reaction of Na with DMC/EC electrolyte. The foam structure, subsequently transformes into a second SEI, is electrochemically inactive and reduces the cyclability of the battery. Overall, the results demonstrate the powerful synergy achieved by coupling in situ ec-TEM and GC/MS techniques.

High-performance cellulose-based nanostructured carbons for rechargeable batteries

Binder-free, highly porous carbon nanofibers (CNFs) with novel sponge-like pore structures were synthesized for the first time via centrifugal spinning of cellulose-based polymers, and SnO2 was introduced to improve the electrochemical performance. Cellulose-based binder-free centrifugally spun carbon-coated SnO2/carbon nanofibers (C@SnO2/CNFs) were employed as anodes in Na-ion batteries. Owing to their highly porous morphology with novel sponge-like pore structures and SnO2 nanoparticles providing rapid Na-ion transport, better electrolyte accessibility, and good mechanical strength, the C@SnO2/CNFs showed outstanding electrochemical performance, with a high reversible capacity of 660 mAh/g at 50 mA/g, high rate capability, and excellent cycling performance. The specific capacity of C@SnO2/CNFs was approximately 390 mAh/g after 2000 cycles at 0.2 A/g. These results prove that the combination of centrifugal spinning, carbon coating, and heat treatment is a promising and sustainable approach for creating cellulose-based carbon nanostructures with highly porous structures that can be used to synthesize high-performance electrodes for energy storage systems.

Optimizing Hard Carbon Anodes from Agricultural Biomass for Superior Lithium and Sodium Ion Battery Performance.

Biomass-derived carbon materials are gaining attention for their environmental and economic advantages in waste resource recovery, particularly for their potential as high-energy materials for alkali metal ion storage. However, ensuring the reliability of secondary battery anodes remains a significant hurdle. Here, we report Areca Catechu sheath-inner part derived carbon (referred to as ASIC) as a high-performance anode for both rechargeable Li-ion (LIBs) and Na-ion batteries (SIBs). We explore the microstructure and electrochemical performance of ASIC materials synthesized at various pyrolysis temperatures ranging from 700 to 1400 °C. ASIC-9, pyrolyzed at 900 °C, exhibits multilayer stacked sheets with the highest specific surface area, and the least lateral size and stacking height. ASIC-14, pyrolyzed at 1400 °C, demonstrates the most ordered carbon structure with the least defect concentration and the highest stacking height and an increased lateral size. ASIC-9 achieves the highest capacities (676 mAh/g at 0.134 C) and rate performance (94 mAh/g at 13.4 C) for hosting Li+ ions, while ASIC-14 exhibits superior electrochemical performance for hosting Na+ ions, maintaining a high specific capacity after 300 cycles with over 99.5 % Coulombic efficiency. This comprehensive understanding of structure-property relationships paves the way for the practical utilization of biomass-derived carbon in various battery applications.

State change of Na clusters in hard carbon electrodes and increased capacity for Na-ion batteries achieved by heteroatom doping

Although heteroatom doping is an effective method to improve the capacity of hard carbon (HC) anodes in Na-ion batteries (NIBs), the complicated structure of HC leads to uncertainty when understanding the effects of heteroatom doping on sodium storage. This study shows the effects of phosphorus and sulfur doping to HC on sodium storage using solid-state NMR to improve the capacity of HC prepared by the carbonization of resorcinol formaldehyde (RF) resin at 1100 °C. Heteroatom doping increased the battery capacity of the HC, especially the plateau capacity, but the interlayer distance of the carbon layers in the HC did not expand considerably. 23Na solid-state NMR revealed that heteroatom doping facilitates the formation of quasi-metallic sodium clusters, thereby contributing to the plateau capacity increase. The metallicity of the sodium clusters in heteroatom-doped HC samples was controlled by the amount of doped-phosphorous. XPS and 31P NMR detected various phosphorus sites such as phosphine and phosphine oxide in the carbon structure.

Prussian blue analogue derived porous hollow nanocages comprising polydopamine-derived N-doped C coated CoSe2/FeSe2 nanoparticles composited with N-doped graphitic C as an anode for high-rate Na-ion batteries

CoFe-Prussian blue analogue (CoFe-PBA) templated N-doped graphitic carbon (NGC) and polydopamine-derived carbon (PDA-20) double-coated CoSe2/FeSe2 nanoparticles are introduced as anodes for highly efficient sodium-ion batteries (SIBs). These nanoparticles are encapsulated within porous hollow nanocages, which exhibit remarkable stability in cyclic performance. The synthesis method involved co-precipitation, followed by PDA coating at varying concentrations and a subsequent selenization process. This resulted in the creation of (Co,Fe)Se-NGC nanocages, (Co,Fe)Se-NGC@PDA-20 hollow nanocages, and (Co,Fe)Se-NGC@PDA-100 filled nanocages. This strategic preparation approach leverages the synergistic effects of dual carbon coating, resulting in highly conductive and porous nanostructures. These structures facilitate rapid charge species diffusion, efficient electrolyte infiltration, and effective management of volumetric changes. When used as anodes for SIBs, the (Co,Fe)Se-NGC@PDA-20 hollow nanocages demonstrate impressive structural robustness and high-rate performance. They exhibit remarkable structural integrity, maintaining stable cycling performance for up to 200 cycles at 0.5 and 1.0 A g−1. In terms of rate capability, the hollow nanocages exhibit a high discharge capacity of 126 mA h g−1 at 10 A g−1. This clearly highlights the structural advantages of the prepared hollow nanocages.

Density functional theory study of molecular pillared graphene for High-Performance Sodium-Ion batteries

This study investigates the potential of molecular pillared graphene (MPG) as anode materials for Na-ion batteries using density functional theory (DFT) calculations. Two distinct MPG structures were designed by varying the organic pillar molecule’s chemical composition. The investigated MPGs comprise two parallel graphene layers linked by naphthalene or pyrene via the formation of five-membered boroxine rings. Cohesive energy analysis and ab-initio molecular dynamics simulations confirm the structural stability of these materials. The results demonstrate high Na mobility within the MPG structures due to the low energy barrier for diffusion. Furthermore, the layered structure facilitates Na-ion insertion, leading to exceptional theoretical capacitances calculated to be 832 and 858 mAh/g. The combination of low diffusion barriers and high theoretical capacities suggests MPG as a promising candidate for Na-ion battery anodes. Additionally, Na adsorption induces metallic behavior in the MPG structures, a crucial prerequisite for efficient ion diffusion in anode materials.

The C-BixSnSb composite toward fast-charging and long-life sodium-ion batteries

Sodium ion batteries (SIBs) fitted with high-rate and high-capacity anodes are attractive for their higher energy density and faster charging capability. However, it is still a challenge to develop high-energy SIBs with high power and long life, due to the sluggish kinetic and limited Na+ insertion in electrode materials. The inherent crystal structure and constituent element are two important factors to resolve the critical issues faced above. Taking the merits of layer-structure and middle-entropy, herein, we proposed and designed a high ion-conductive composite combing with ternary alloy and layered BixSnSb@C nanofibers, which eliminate ion migration barriers while maintaining the structural framework for superior rate property and cycle stability. Used as anode for SIBs, the multiphase BixSnSb@C with adjustable Bi content exhibits excellent Na storage capability as compared to their single phase counterpart. Specially, up to a rate of 132C (50 A g−1), the capacity is still as high as 400 mAh g−1, meanwhile, after 5000 charge and discharge cycles at a current density of 12C, the capacity still maintains 85 % of its initial capacity, which outperform the individual Bi- or SnSb-based materials. The superior electrochemical performances originate from the middle-entropy nature and layer structure of BiSnSb alloy, which can provide more channels for fast Na+ transport, and accommodate large volume changes. Besides, the activity energy and ions transport resistance of Na+ in different composites were evaluated. Furthermore, the full-cell coupled with NaNi1/3Fe1/3Mn1/3O2 as cathode was formed and a capacity retention of ∼80 % is realized in 100 cycles. The results show that the BixSnSb@C is a potential anode for fast-charging Na-ion batteries and could be used to guide the design of multi-component alloy-base anodes.

Unlocking plateau capacity with versatile precursor crosslinking for carbon anodes in Na-ion batteries

As the precursor material inherently determines the fundamental structure of hard carbons, a direct manipulation of precursors at the molecular level promises enhanced flexibility in designing hard carbon architectures, which plays a pivotal role in dictating the final microstructural properties and, ultimately, the overall sodium storage performance. In this study, we present a novel generalized strategy utilizing P and O double cross-linking to convert pitch into a thermosetting precursor, creating copious micropores within pitch-based carbon. These micropores serve as essential pathways and active binding sites for sodium ion transport and storage, leading to pitch-derived hard carbons with a remarkable specific capacity of 416.1 mAh/g and an impressive initial Coulombic efficiency of 89.7%. Extensive study revealed a strong correlation between the increased plateau capacity and the closed pore volume, validating the micropore-driven sodium ion storage mechanism. Our findings underscores the groundbreaking significance of cross-linking in precursor modification, paving the way for the design and synthesis of high-performance hard carbon anodes for next-generation Na-ion batteries.

Binary Co3S4/SnS chalcogenide composites anchored on graphene oxide and carbon nanotubes as anodes for Na-ion batteries

Hetero-architectures are smart for modern energy storage appliances owing to fast charge transportation. However, the smooth and rational assembly with adequate Na+ storage kinetics so far is a significant challenge. Herein, transition-bimetallic sulfides hetero-structured Co3S4/SnS (CTS) and its composites implanted in reduced graphene oxide (CTS.rGO) and carbon nanotubes (CTS.CNTs) have been synthesized and employed as anodes for sodium-ion batteries. The use of highly conductive nature of carbon frames benefits the stability and conductivity of the bimetallic sulfides CTS composites. As a result, the CTS.CNTs delivered a charge capacity 298 mAh/g, whereas CTS.rGO and bare CTS exhibited 229 and 76 mAh/g after 200cycles at 0.05C. In addition, the CTS.CNTs and CTS.rGO displayed excellent rate performance at different rates (0.05C – 10.0C) and upon reversing the C-rate to 0.05C, CTS.CNTs fully restored the charge capacity 329 mAh/g while CTS.rGO restored to 293 mAh/g. The ultra-cyclic stability and improved rate performance enlightening the synergistic effect between CTS and carbon conducting agents. Moreover, the CTS.CNTs displayed the lowest charge transfer resistance (Rct = 604 Ω) as compared to CTS.rGO and bare CTS (Rct = 618 Ω, Rct = 642 Ω), indicating the rapid charge transport.

Mechanical Activation of Graphite for Na-Ion Battery Anodes: Unexpected Reversible Reaction on Solid Electrolyte Interphase via X-Ray Analysis.

Although sodium-ion batteries (SIBs) offer promising low-cost alternatives to lithium-ion batteries (LIBs), several challenges need to be overcome for their widespread adoption. A primary concern is the optimization of carbon anodes. Graphite, vital to the commercial viability of LIBs, has a limited capacity for sodium ions. Numerous alternatives to graphite are explored, particularly focusing on disordered carbons, including hard carbon. However, compared with graphite, most of these materials underperform in LIBs. Furthermore, the reaction mechanism between carbon and sodium ions remains ambiguous owing to the structural diversity of disordered carbon. A straightforward mechanical approach is introduced to enhance the sodium ion storage capacity of graphite, supported by comprehensive analytical techniques. Mechanically activated graphite delivers a notable reversible capacity of 290.5 mAh·g-1 at a current density of 10 mA·g-1. Moreover, it maintains a capacity of 157.7 mAh·g-1 even at a current density of 1 A·g-1, benefiting from the defect-rich structure achieved by mechanical activation. Soft X-ray analysis revealed that this defect-rich carbon employs a sodium-ion storage mechanism distinct from that of hard carbon. This leads to an unexpected reversible reaction on the solid electrolyte surface. These insights pave the way for innovative design approaches for carbon electrodes in SIB anodes.

Liquid Na-K alloy is not viable anode material for High-Performance Na-Ion batteries

Liquid sodium–potassium alloy NaxK100-x at. % (≈14 < x < 70 at room temperature) has been proposed as a dendrite-free liquid metal anode for Na-ion batteries. Nevertheless, controversy surrounds the use of NaxK100-x as a Na-ion battery anode due to the presence of the two competitive redox-active species, Na/Na+ and K/K+. To resolve this ongoing controversy, we use x-ray diffraction (XRD) and cryogenic-focused ion beam/scanning electron microscopy (cryo-FIB/SEM) to investigate liquid Na50K50 electrodes cycled in symmetric cells using Na-ion electrolytes. We find that the reaction overpotential abruptly increases after ≈ 40 cycles. Cryo-FIB/SEM reveals the precipitation of K salts, which confirms that K/K+ species are redox-active in Na-ion electrolytes. Such an effect progressively leads to irreversible leaching of K from the initial liquid Na50K50 composition, resulting in a loss of liquid metal properties. Consequently, our results suggest that NaxK100-x cannot sustainably function as a liquid metal anode in Na-ion batteries.