Anode For Sodium-ion Batteries Research Articles

Synergistic Effects of Confinement Structure and Local‐Expanded Interlayer Spacing in Fe2Mo3O8@C@MoS2 Toward High‐Efficient Sodium Ion Storage

AbstractDeveloping multicomponent composite materials with delicate morphology and tailored structure is of vital importance for designing advanced sodium‐ion batteries (SIBs). Herein, a confinement‐structured Fe2Mo3O8@C@MoS2 with local‐expanded interlayer spacing is designed via high‐temperature phase transition from FeMoO4 to Fe2Mo3O8 and the tactically introducing dopamine molecules into the interlayer of MoS2 nanosheets. By analysis of the in situ generated solid electrolyte interphase film in different electrolytes, the favorable compatibility of Fe2Mo3O8@C@MoS2 in ether‐based electrolytes is well illustrated. Importantly, the sodium storage mechanism and detailed structural evolution of Fe2Mo3O8 are established for the first time by in situ X‐ray diffraction. Furthermore, theoretical calculations indicate the unique structure facilitates internal charge transfer and enhances Na+ adsorption ability. Thanks to the unique confinement structure, local‐expanded interlayers and robust framework, the Fe2Mo3O8@C@MoS2 composite achieves a high reversible specific capacity of 636 mAh g‒1 at 0.1 A g‒1, excellent rate capability (301 mAh g‒1 at 5.0 A g‒1) and ultralong cycling stability (365 mAh g–1 after 6000 cycles at 2.0 A g–1). The study provides an essential understanding of the Na storage mechanism of Fe2Mo3O8 and a promising strategy for constructing high‐performance anodes for SIBs.

Modulating the graphitic domains of hard carbons via tuning resin crosslinking degree to achieve high rate and stable sodium storage

Sodium-ion batteries (SIBs) are regarded as an outstanding alternative to lithium-ion batteries (LIBs) due to abundant sodium sources and their similar chemistry. As a most promising anode of SIBs, hard carbons (HCs) receive extensive attention because of their low potential and low cost, but their rational design for commercial SIBs is restricted by their variable and complicated microstructure, which is analogous to that of graphite in LIBs. Herein, a series of controllable HC materials derived from 3-aminophenol formaldehyde resin (AFR) were designed and fabricated. We discover that the optimized HC features expanded graphite regions, highly developed nanopores, and reduced defect content, contributing to the enhanced Na+ storage. This optimization is achieved by adjusting the resin crosslinking degree of the precursor. Specifically, a resin precursor with a higher crosslinking degree can produce HC with a larger interlayer distance, relatively higher crystallinity, and a lower specific surface area. Encouragingly, the as-optimized AFR-HC electrode manifests superior electrochemical performance in the aspect of high capacity (383 mAh·g-1 at 0.05 A·g-1), better rate capability (140 mAh·g-1 at 20 A·g-1), and high initial coulombic efficiency (82%) than other contrast samples. Moreover, the as-constructed full cell coupled with a Na3V2(PO4)3 cathode shows an energy density of 250 Wh·kg-1. Together with the simple synthesis, cost-efficiency of the precursors and superior electrochemical performance, AFR-HCs are promising for the commercial application.

Quasi-diffusion controlled high rate sodium-ion storage performance of flame pyrolysis derived spherical hard carbon

Hard carbon (HC) is identified as a potential anode for sodium ion batteries (SIBs) due to its outstanding electrochemical performance. However, selection of synthesis routes and its precursors remain crucial to develop the HC of desired microstructures for enhanced sodium-ion storage. Herein, we employed novel flame pyrolysis route to prepare spherical HC nanoparticles (<100 nm) from a liquid precursor derived from a low-cost bio-source. The as prepared carbon has been subjected to different calcination temperatures to optimize the porosity and surface area in order to achieve maximum sodium ion storage. The HC calcined at 1200 °C has shown the optimum electrochemical performance with a high reversible capacity of ∼287 mAh/g at 0.1C (1C = 300 mA/g). It shows 72 % of capacity retention after 490 cycles when cycled at 1C, with initial reversible specific capacity of ∼235 mAh/g. Excellent rate performance has been seen even at 20 C (6 A/g) with high specific capacity of 118 mAh/g at 70 % capacity retention after 2000 cycles, which is one of the highest values reported so far. Structural and morphological characterization of HC prepared at different temperatures are carried out using X-ray powder diffraction (XRD), small angle X-ray scattering (SAXS), Raman spectroscopy, scanning electron microscopy (SEM) and transmission electron microscopy (TEM) techniques. Particle size and morphology altogether have played significant role in achieving high specific capacity and C-rate performance by providing shorter diffusion path and larger sodium ion storage sites.

Pure and (Sn or Mg) Doped GeFe2O4 as Anodes for Sodium-Ion Batteries

Pure and (Sn or Mg) Doped GeFe2O4 as Anodes for Sodium-Ion Batteries

Investigation of hexagonal boron nitride monolayer with pores as an anode material for sodium-ion batteries

The hexagonal boron nitride monolayer (h-BNML) used as an anode material for metal-ion batteries was assumed pristine form. However, inspired by the imperfections in natural materials, this study investigates the effect of defects on the electrochemical properties of h-BNML. Within the current piece of research, h-BNML with pores is introduced to develop an anode material for sodium ion battery (SIBs) by undertaking density-functional theory (DFT) computations. During the diffusion and storage process of Na ions, the pores effect was thoroughly investigated. The boron atoms were removed from the structure of the pure h-BNML in order to form the h-BNML with pores, which mimicked the pore formation. Based on the DFT results, after the pore formation, the h-BNML retained its planarity. Following the introduction of vacancies, significant alterations occurred in the electronic structure characteristics of h-BNML within the pores, facilitating the effective adsorption of Na ions within the pore. The results of quantum theory of atoms in molecules indicated that there were interactions between the pores and Na ions through an electrostatic-type attraction. The h-BNML with pores was capable of retaining a large number of Na ions at its surface without any change in its planar structure. This led to an increase in its theoretical specific capacity, which increased with porosity. Hence, unlike the pure h-BNML, the pore formation improved the diffusion of Na ions. This can be promising to designing highly efficient anodes for SIBs. The methodological approach in this study can be used for tailoring porous BN materials for SIBs.

Preparation of nanodiamonds modified hard carbon with uniform spherical feature for improving sodium-ion storage performances

Sodium-ion batteries (SIBs) have received remarkable attention due to their abundant sodium (Na) content and low resources cost. However, the absence of high-performance anode materials make carbon-based SIBs still a challenge. Herein, nano-diamonds (NDs) modified gleditsia japonica shell carbon to form a uniform carbon microsphere, which improves the graphitization degree and Na ion adsorption, NDs also act as a strong scaffold to maintain its stability. This spherical carbon-based material exhibits superior performances including the enhanced capacity (270 mA h g−1 at 0.2C after 100 cycles) and long-cycle stability (155 mA h g−1 at 2C after 1000 cycles) when incorporated into SIBs. This work provides a green and simple synthesis strategy for fabricating high performance porous spherical carbon used for SIBs anode.

High capacity and long service in sodium-ion batteries achieved by the refinement of BiOCl from lamellar to flower-like in ether electrolyte

Sodium-ion batteries (SIBs) have emerged as a promising contender in power systems owing to their cost-effectiveness and safety advantages. However, alloy-type anode materials, crucial for SIB performance, often face challenges such as significant volume expansion and rapid capacity decay at high current densities. In this study, an ion-exchange strategy is used to fabricate ultra-thin and porous BiOCl nanosheets (UTP BiOCl NS) as an anode material for SIB. Remarkably, lamellar UTP BiOCl NSs can transform a flower-like shape in ether electrolytes. This structural change is beneficial in shortening the Na+ transport path, which facilitates rapid electrolyte entry and enhances the dynamic behavior of SIBs. Electrochemically, UTP BiOCl NS demonstrates an exceptional capacity of 212.4 mAh/g and high service stability of up to 3000 cycles at a high current density of 5 A/g, showcasing exceptional durability and promising application potential. Furthermore, the SIB full-cell, coupled with a Na3V2(PO4)3 cathode and UTP BiOCl NS anode, enables an outstanding sodium storage capacity of 140.5 mAh/g and powers a 3 W bulb. This research provides a strategic approach for identifying suitable SIB anodes and aims to inspire researchers to focus on advancing anode materials in SIBs.

Heterostructured ZnS/Co embedded in pinecone-like N/S-doped carbon for efficient sodium/lithium storage

Constructing heterogeneous electrodes to confront various electrochemical and structural requirements is demonstrated to be crucial for improving the sodium and lithium storage performances. Herein, a novel design of ZnS/Co heterostructures is expounded with abundant phase boundaries encapsulated in highly-conductive N/S-doped “pinecone”-like carbon framework (ZnS/Co@NSC-450) as a superior anode for sodium ion batteries (SIBs) and lithium-ion batteries (LIBs). In ZnS/Co@NSC-450, the ZnS/Co heterostructures can improve the electronic conductivity of material and stabilize the electrode structure integrity during cycling, while the N/S-doped “pinecone”-like carbon is beneficial for alleviating the volume expansion effect of active materials, providing additional active sites for sodium/lithium storage and ensuring the rapid electron/ion transfer across the electrode. Due to the synergistic effect of multiple components, both the SIBs and LIBs with ZnS/Co@NSC-450 anodes exhibit high-rate capability (476 mAh g−1 at 6.4 A g−1 for SIBs and 387 mAh g−1 at 12.8 A g−1 for LIBs) and outstanding long-term cycling stability (557 mAh g−1 at 2 A g−1 for SIBs after 1500 cycles and 767 mAh g−1 for LIBs after 1000 cycles). These results disclose the promising potential of ZnS/Co@NSC-450 toward high-performance SIBs and LIBs.

TD-graphene: Theoretical prediction of a high-performance anode material for sodium-ion batteries with intrinsic metallicity, high capacity, and fast ion mobility

The utilization of pristine graphene as an anode material in sodium-ion batteries (SIBs) is limited by its inherent chemical inertness toward Na-ions. To address this issue, we propose a two-dimensional carbon allotrope (named as TD-graphene) by assembling tricyclo[4.4.1.11,6]dodecane (C12H20) skeleton. The topological non-hexagonal feature of C12H20 increases the degree of local carbon-ring disorder and introduces additional electron-deficient regions on the surface, thus enhancing the adsorption capability of Na. TD-graphene demonstrates exceptional stability across the energetic, thermodynamic, dynamic, and mechanical aspects. As a promising anode for SIBs, it exhibits an intrinsic metallicity, an ultra-high storage capacity (1487.58 mA h g−1), a low diffusion barrier (0.20 eV), a low average open-circuit voltage (0.33 V), and a small lattice expansion (0.6%). The presence of solvents with high dielectric constants improves the adsorption and migration capability of Na. Furthermore, taking into account the limitation of single-layer materials in practical applications, we employ h-BN as a promising substrate for TD-graphene, which can boost the Na adsorption and diffusion performance. These results render TD-graphene as a promising high-performance anode material for SIBs.

Exploring Carbonization Temperature to Create Closed Pores for Hard Carbon as High-Performance Sodium-Ion Battery Anodes.

Biomass-derived porous carbon materials are meaningful to employ as a hard carbon precursor for anode materials of sodium-ion batteries (SIBs) from a sustainability perspective. Here, a straightforward approach is proposed to develop rich closed pores in pinenut-derived carbon, with the aim of improving Na+ plateau storage by adjusting the pyrolysis temperature. The optimized sample, namely the pinenut-derived carbon at 1300 °C, demonstrates remarkable reversible specific capacity of 278 mAh g-1, along with a high initial Coulomb efficiency of 85% and robust cycling stability (with a capacity retention of 89% after 800 cycles at 0.2 A g-1). In situ and ex situ analyses unveil that the developed closed pores play a significant role in enhancing the plateau capacity, providing compelling evidence for the "adsorption-filling" mechanism. Moreover, the corresponding full-cell achieves a high energy density of 245.7Wh kg-1 (based on the total weight of both electrode active materials) and exhibits outstanding rate capability (191.4 mAh g-1 at 3 A g-1).

Robust pseudocapacitive Na+ intercalation induced by MoS2 on active Mo2C current collector interface for high areal capacity sodium-ion batteries

Sodium-ion batteries (SIBs) have emerged as compelling alternatives in the realm of electrochemical energy devices, poised to substitute lithium-ion batteries (LIBs). The primary challenge encompasses not only the scarcity of anode materials exhibiting exceptional Na+ storage capacity but also the endeavor to achieve high areal capacity. To address this challenge, a comprehensive strategy is proposed that entails utilizing a highly conductive molybdenum dicarbide (Mo2C) current collector (denoted as CCM) as a supporting scaffold for the bottom-up growth of molybdenum disulfide nanosheets (MoS2, serving as the main active component) (denoted as CCM@MoS2). The CCM improves interfacial bonding with MoS2 nanosheets and offers additional capacity to accommodate the increased Na+ insertion activity. Both theoretical and kinetic analyses reveal that the enhanced Na+ storage properties primarily stem from favorable adsorption energy, reduced diffusion barrier, and intercalation pseudocapacitance due to the strong electronic interfacial interaction between active CCM and MoS2. Hence, the as-prepared optimized CCM@MoS2 electrode exhibits a superior areal capacity of 6.36 mAh cm−2 at 0.4 mA cm−2, excellent rate capability of 1.02 mAh cm−2 at 24 mA cm−2 and long cycle life up to 500 cycles at 4 mA cm−2. Interesting, our as-prepared CCM@MoS2 electrode shows better performance for Na+ storage than Li+ storage at higher current density, affirming the enhanced kinetics in our architecture. This work proposes a rational strategy to enhance the areal capacity and stability of MoS2-based anode for SIBs and beyond.

Hybrid-Mechanism Synergistic Flexible Nb2O5@WS2@C Carbon Nanofiber Anode for Superior Sodium Storage.

Sodium-ion batteries (SIBs) have demonstrated remarkable development potential and commercial prospects. However, in the current state of research, the development of high-energy-density, long-cycle-life, high-rate-performance anode materials for SIBs remains a huge challenge. Free-standing flexible electrodes, owing to their ability to achieve higher energy density without the need for current collectors, binders, and conductive additives, have garnered significant attention across various fields. In this work, we designed and fabricated a free-standing three-dimensional flexible Nb2O5@WS2@C carbon nanofiber (CNF) anode based on a hybrid adsorption-intercalation-conversion mechanism of sodium storage, using electrospinning and hydrothermal synthesis processes. The hybrid structure, aided by synergistic effects, releases the advantages of all materials, demonstrating a superior rate performance (288, 248, 211, 158, 90, and 48 mA h g-1 at the current density of 0.2, 0.5, 1, 2, 5, and 10 A g-1, respectively) and good cycling stability (160 mA h g-1 after 200 cycles at 1 A g-1). This work provides certain guiding significance for future research on hybrid and flexible anodes of SIBs.

One-step Solid-State Synthesis of V1.13Se2/V2O3 Heterostructure as a High Pseudocapacitance Anode for Fast-Charging Sodium-Ion Batteries.

Sodium-ion batteries (SIBs) offer several benefits, including cost-efficiency and fast-charging characteristics, positioning them as attractive substitutes for lithium-ion batteries in energy storage applications. However, the inferior capacity and cycling stability of electrodes in SIBs necessitate further enhancement due to sluggish reaction kinetics. In this respect, the utilization of heterostructures, which can provide an inherent electric field and abundant active sites on the surface, has emerged as a promising strategy for augmenting the cycling stability and rate features of the electrodes. This work delves into the utilization of V1.13Se2/V2O3 heterostructure materials as anodes, initially fabricated via a simplified one-step solid-state sintering technique. The high pseudocapacitance and low characteristic relaxation time constant give the V1.13Se2/V2O3 heterostructure impressive properties, such as a high capacity of 328.5 mAh g-1 even after 1500 cycles at a high current density of 2 A g-1 and rate capability of 278.9 mAh g-1 at 5 A g-1. Moreover, the assembled sodium-ion full battery delivers a capacity of 118.5 mAh g-1 after 1000 cycles at 1 A g-1. These findings provide novel insight and guidance for the rapid synthesis of heterojunction materials and the advancement of SIBs.

Electrochemical Behavior of the Biomass Hard Carbon Derived from Waste Corncob as a Sodium-Ion Battery Anode

Electrochemical Behavior of the Biomass Hard Carbon Derived from Waste Corncob as a Sodium-Ion Battery Anode

Deciphering multistep transformation mechanism of cobalt-vanadium bimetallic sulfides anode in sodium storage

Transition metal sulfides as a high specific capacity sodium-ion batteries (SIBs) anode which have been suffering from successive phase transitions bringing about stress changes, poor electronic conductivity and ineffective ion transport kinetics. Combining self-sacrificial templates and ion-exchange transition reaction mechanisms, herein, cobalt, vanadium bimetallic sulfides hollow nano-cubic boxes with nitrogen-doped nanocarbon coating layer (CoV2S4@NC) are designed to solve these symbiosis problems. With a combination of in-situ Raman, ex-situ XPS/TEM, and density-functional theory calculations, the synergistically coordination mechanism between cobalt and vanadium binary metal during multi-step conversion processes is responsible for the faster charge transfer kinetics and boosted Na+ pseudocapacitance storage capability. Furthermore, the hollow cubic structure combined with the carbon shell layer can release the internal stress during phase transitions and avoid the recurrent growth of SEI film by volume change during the electrochemical process, thus realizing a superior electrode/electrolyte interface. Thus, when used as anode materials for SIBs, the prepared anode materials display excellent electrochemical performance, delivering capacity of 492 mA h g−1 at a current density of 10 A g−1 and high capacity stability with 484 mAh g−1 after 1000 cycles at 5 A g−1. More importantly, the assembled full cell (Na3V2(PO4)3//CoV2S4@NC) also shows high capacity of 574 mAh g−1 with 94.7% capacity retention after 85 cycles, suggesting the potential application of bimetallic sulfides in SIBs.

Electrodeposition of Tin and Antimony-Based Anode Materials for Sodium-Ion Batteries

Tin antimonide (SnSb) is a promising alloying anode for sodium-ion batteries due to its high theoretical capacity and relative stability. The material is popular in the battery field, but, to our knowledge, few studies have been conducted on the influence of altering Sn and Sb stoichiometry on anode capacity retention and efficiency over time. Here, Sn-Sb electrodes were synthesized with compositional control by optimizing electrodeposition parameters and stoichiometry in solution and the alloys were cycled in sodium-ion half-cells to investigate the effects of stoichiometry on both performance and electrochemical phenomena. Higher concentrations of antimony deposited into the films were found to best maintain specific capacity over 270 cycles in the tin-antimony alloys, with each cell showing a slow, gradual decrease in capacity. We identified that a 1:3 ratio of Sn:Sb retained a specific capacity of 486 mAh g−1 after 270 cycles, highlighting a need to explore this material further. These results demonstrate how control over stoichiometry in Sn-Sb electrodes is a viable method for tuning performance.

Synergistic Effect of 3D Electrode Architecture and In Situ Carbon Coating on the Electrochemical Performance of SnO2 Anodes for Sodium-Ion Batteries

SnO2, owing to its high theoretical capacity of 1378 mAh g−1 and low sodium insertion potential, is one of the attractive anode materials for Sodium-ion batteries (SIBs). However, extensive volume expansion (∼300 %), significant capacity loss, particle agglomeration, and low conductivity (1.82 × 10−8 S cm−1) of SnO2 limit its commercial applications. In this work, SnO2 nano-particles have been synthesized via a one-step hydrothermal method. Subsequently, 3D electrode architecture is developed using pitch-coated SnO2 nanomaterial onto carbon fiber (CF) current collector to mitigate the inherent challenges of SnO2 anode. Compared to the conventional SnO2 electrode, the optimized CF-SnO2- carbon composite electrodes show an excellent second-cycle stable capacity of 843 mAh g−1 at 30 mA g−1 with 95 % capacity retention after 100 cycles. This CF-SnO2-carbon composite electrode further delivers a stable capacity of 419 mAh g−1 at 300 mA g−1, having 80 % capacity retention after 200 cycles, and shows excellent C-rate performance. Conductive CF backbone and carbon coating accommodate the volume expansion of the active material, acting as a buffer matrix and reducing the electrode pulverization. This work entails a carbon fiber-based electrode engineering approach to fabricate a binder-less metal current collector-free freestanding electrode as a potential anode for SIBs.

Intrinsically Nitrogen-Enriched Biomass-Derived Hard Carbon with Enhanced Performance as a Sodium-Ion Battery Anode

Intrinsically Nitrogen-Enriched Biomass-Derived Hard Carbon with Enhanced Performance as a Sodium-Ion Battery Anode

Ni‐Single Atoms Modification Enabled Kinetics Enhanced and Ultra‐Stable Hard Carbon Anode for Sodium‐Ion Batteries

AbstractHard carbon with randomly oriented interlayers is the most promising candidate for the anode of commercial sodium‐ion batteries (SIBs). Nevertheless, its sluggish sodium storage kinetics and unsatisfactory cycling stability are bottlenecks to its implementation. Herein, a metal‐single atom modification strategy is proposed to construct a Ni‐single atoms modified N, P co‐doped hard carbon (Ni‐NPC) with a Ni content of ≈5.65 wt%. As an anode for SIBs, Ni‐NPC exhibits far superior initial Coulombic efficiency, reversible specific capacity, rate capability, and cycling stability to N, P co‐doped hard carbon. Combining in situ EIS and ex‐situ XPS,this study reveals that Ni‐single atoms modulate the composition of the solid electrolyte interface layer, thereby improving the cycling stability of Ni‐NPC. Theoretical calculation and kinetics analysis suggest that Ni‐single atoms are the promoters of the diffusion of Na+. Furthermore, with the aid of systematic in situ characterizations, the structural evolution of Ni‐NPC at different sodium storage stages is identified. This work proposes a potential strategy for simultaneously improving the sodium storage kinetics and cycling stability of hard carbon anodes, and elucidates the improvement mechanism of this strategy.

Enhancing waste hemp hurd-derived anodes for sodium-ion batteries through hydrochloric acid-mediated hydrothermal pretreatment

Waste hemp hurd (WHH) was used as a sustainable feedstock for producing hard carbon-based anodes for sodium-ion batteries (SIBs). Two easily scalable production pathways were tested and compared: (1) pyrolysis (at 500 °C) and subsequent annealing at 800, 1000 or 1200 °C, and (2) hydrothermal pretreatment (at 180 °C) and subsequent annealing at the above-mentioned highest temperatures. Results indicated that when a HCl (2 mol m−3) aqueous solution was used as hydrothermal medium, the textural, structural and surface chemistry features linked to the electrochemical performance of the resulting hard carbons improved. The WHH-derived electrode produced via HCl-mediated hydrothermal pretreatment and subsequent annealing at 1000 °C showed an exceptional electrochemical performance in terms of specific capacity (535 mA h g−1 at 30 mA g−1) and rate capability (372, 156, 115, and 83 mA h g−1 at 0.1, 0.5, 1, and 2 A g−1, respectively) when an ester-based electrolyte was used (NaTFSI in EC/DMC). Using an ether-based electrolyte (NaPF6 in diglyme) improved both the ICE (from 69% to 78%) and cycling stability (85% of capacity retention after 300 cycles at 1 A g−1; 91% when current rate returned to 0.1 A g−1). In summary, relatively low-cost WHH-derived carbons are able to deliver an exceptional performance, much better than that reported so far for other biomass-derived carbons, and even close to that exhibited by more expensive and complex composite and hybrid materials.