Sodium-ion Batteries Research Articles

An innovative synthesis of carbon-coated TiO2 nanoparticles as a host for Na+ intercalation in sodium-ion batteries.

In this work, an innovative route to synthesize an anatase TiO2@C composite is presented. The synthesis was conducted using a soft chemistry microwave-assisted method using titanium(IV) butoxide as a titanium precursor. The residual (un)converted titanium precursor remaining after TiO2 synthesis was used as a carbon precursor and thermally treated under H2 to obtain nanoparticles of the TiO2@C composite. A superior reversible specific capacity was obtained with TiO2@C (120 mA h g-1 at a C/20 rate, 3rd cycle) compared to that with pristine TiO2 (66.5 mA h g-1 at a C/20 rate, 3rd cycle), in agreement with the importance of carbon coating addition to TiO2 nanoparticles as negative electrode materials for sodium-ion batteries.

High-Entropy Configuration Strategy to Build High Performance Na-Ion Layered Oxide Cathodes Derived from Simple Techniques.

Layered transition metal oxides are commonly used as the cathode materials in sodium-ion batteries due to their low cost and easy manufacturing. However, the application is hindered by poor rate performance and complex phase transitions. To address these challenges, a new seven-component high-entropy layered oxide cathode material, O3-NaNi0.25Fe0.15Mn0.3Ti0.1Sn0.05Co0.05Li0.1O2 (HEO) has been developed. The entropy stabilization effect plays a crucial role in improving the performance of electrochemical systems and the stability of structures. The HEO exhibits a specific discharge capacity of 154.1 mA h g-1 at 0.1 C and 94.5 mA h g-1 at 7 C. In-situ and ex-situ XRD results demonstrate that the HEO effectively retards complex phase transitions. This work provides a high-entropy design for the storage materials with a high energy density. Meanwhile, it eliminates industry doubts about the performance of sodium ion layered oxide cathode materials.

Vacancy-Defect Ternary Topological Insulators Bi2Se2Te Encapsulated in Mesoporous Carbon Spheres for High Performance Sodium Ion Batteries and Hybrid Capacitors.

Ternary topological insulators have attracted worldwide attention because of their broad application prospects in fields such as magnetism, optics, electronics, and quantum computing. However, their potential and electrochemical mechanisms in sodium ion batteries (SIBs) and hybrid capacitors (SIHCs) have not been fully studied. Herein, a composite material comprising vacancy-defects ternary topological insulator Bi2Se2Te encapsulated in mesoporous carbon spheres (Bi2Se2Te@C) is designed. Bi2Se2Te with ample vacancy-defects has a wide interlayer spacing to enable frequent insertion/extraction of Na+ and boost reaction kinetics within the electrode. Meanwhile, the Bi2Se2Te@C with optimized yolk-shell structure can buffer the volume variation without breaking the outer protective carbon shell, ensuring structural stability and integrity. As expected, the Bi2Se2Te@C electrode delivers high reversible capacity and excellent rate capability in half SIB cells. Various electrochemical analyses and theoretical calculations manifest that Bi2Se2Te@C anode confirms the synergistic effect of ternary chalcogenide systems and suitable void space yolk-shell structure. Consequently, the full cells of SIB and SIHC coupled with Bi2Se2Te@C anode exhibit good performance and high energy/power density, indicating its widespread practical applications. This design is expected to offer a reliable strategy for further exploring advanced topological insulators in Na+-based storage systems.

Amphoteric Supramolecular Nanofiber Separator for High‐Performance Sodium‐Ion Batteries

The separator is an essential component of sodium‐ion batteries (SIBs) to determine their electrochemical performances. However, the separator with high mechanical strength, good electrolyte wettability and excellent electrochemical performance remains an open challenge. Herein, a new separator consisting of amphoteric nanofibers with abundant functional groups was fabricated through supramolecular assembly of natural polymers for SIB. The uniform nanoporous structure, remarkable mechanical properties and abundant functional groups (e.g. −COOH, −NH2 and −OH) endow the separator with lower dissolution activation energy and higher ion migration numbers. These metrics enable the separator to lower the barrier for desolvation of Na+, accelerate the migration of Na+, and generate more stable solid electrolyte interphase (SEI) and cathode electrolyte interphase (CEI). The battery assembled with the amphoteric nanofiber separator shows higher specific capacity and better stability than that assembled with glass fiber (GF) separator.

Rational design of hollow C@SnS2/SnS@C cubes with N-doping to realize stepwise sodium storage induced structural stability for highly stable cycling performance

Current application of SnS2-based anodes in sodium-ion batteries fails to meet the demand for higher Na+ storage capacity due to the structural pulverization induced by significant volume changes during cycling. Herein, a novel composite of hollow C@SnS2/SnS@C cubes with excellent diffusion kinetics and structural stability from stepwise Na+ storage is designed. The SnS with gentle pseudocapacitive reaction acts as the self-supporter to prevent the collapse of SnS2/SnS heterostructure during the Na+ insertion/extraction. Together with the clamping of double carbon layers and hollow construction, the volume change caused structural instability in heterostructure is effectively alleviated. The rapid transport of electrons and ions within the built-in electric field of heterostructure endows the composite an excellent diffusion kinetics, which is generated from the narrow bandgap and outstanding Na+ absorption of heterostructure according to the first-principle calculation. Thus, the as-prepared composite maintains a remarkable capacity of 547.9 mAh g−1 after 200 cycles at current density of 0.5 A g−1. Even a capacity of 502.5 mAh g−1 with a low attenuation rate of 0.035 % per cycle is achieved at 2 A g−1 after 1000 cycles. The work proposes an effective approach to achieve effective Na + storage of SnS2-based anodes with long-lasting structural stability.

Precision anode vacancy engineering for long-lasting and fast-charging Na-Ion batteries

In the field of energy storage materials, the unique properties of vacancies are highly significant, especially in the optimization of transition metal dichalcogenides (TMDs). However, scaling up these storage solutions remains a considerable challenge. In our study, we successfully synthesized VSe2-x via alleviating selenide content, where vacancies were introduced in situ through a straightforward physical vapor transport process. These vacancies boost the adsorption capacity for sodium ions (Na+), and create additional active sites, thereby minimizing the structural changes in VSe2-x during Na+ storage. Our VSe2-x based negative electrode demonstrates impressive sodium storage capability, offering an exceptional rate performance with a capacity of 346 mAh g−1 at 5 A g−1 and maintaining a remarkable stability of 378 mAh g−1 even after 1400 cycles at 10 A g−1. Additionally, through a combination of theoretical calculations, in situ X-ray diffraction analysis, and ex situ transmission electron microscopy, we have confirmed the creation of vanadium selenide materials containing vacancies. During continuous charging and discharging, these materials facilitate the generation of numerous sodium-containing aggregates with high electronic conductivity. This paper provides a comprehensive exploration of how vacancies in transformed materials can be an effective strategy for efficient rechargeable batteries.

Tetrathiafulvalene carboxylate-based anode material for high-performance sodium-ion batteries.

Organic electrode materials are promising to be applied in sodium ion batteries (SIBs) due to their low cost and easily modified molecular structures. Nevertheless, low conductivity and high solubility in electrolytes still limit the development of organic electrodes. In this work, a carboxylate small molecule (BDTTS) based on tetrathiafulvalene is developed as anode material for SIBs. BDTTS has a large rigid π-conjugated planar structure, which may reduce solubility in the electrolyte, meanwhile facilitating charge transporting. Experimental results and theoretical calculations both support that apart from the four carbonyl groups, the sulfur atoms on tetrathiafulvalene also provide additional active sites during the discharge/charge process. Therefore, the additional active sites can well compensate for the capacity loss caused by the large molecular weight. The as-synthesized BDTTS electrode renders an excellent capacity of 230 mAh g-1 at a current density of 50 mA g-1 and an excellent long-life performance of 128 mAh g-1 at 2C after 500 cycles. This work enriches the study on organic electrodes for high-performance SIBs and paves the way for further development and utilization of organic electrodes.

Manipulating Local Chemistry and Coherent Structures for High-Rate and Long-Life Sodium-Ion Battery Cathodes.

Layered sodium transition-metal (TM) oxides generally suffer from severe capacity decay and poor rate performance during cycling, especially at a high state of charge (SoC). Herein, an insight into failure mechanisms within high-voltage layered cathodes is unveiled, while a two-in-one tactic of charge localization and coherent structures is devised to improve structural integrity and Na+ transport kinetics, elucidated by density functional theory calculations. Elevated Jahn-Teller [Mn3+O6] concentration on the particle surface during sodiation, coupled with intense interlayer repulsion and adverse oxygen instability, leads to irreversible damage to the near-surface structure, as demonstrated by X-ray absorption spectroscopy and in situ characterization techniques. It is further validated that the structural skeleton is substantially strengthened through the electronic structure modulation surrounding oxygen. Furthermore, optimized Na+ diffusion is effectively attainable via regulating intergrown structures, successfully achieved by the Zn2+ inducer. Greatly, good redox reversibility with an initial Coulombic efficiency of 92.6%, impressive rate capability (86.5 mAh g-1 with 70.4% retention at 10C), and enhanced cycling stability (71.6% retention after 300 cycles at 5C) are exhibited in the P2/O3 biphasic cathode. It is believed that a profound comprehension of layered oxides will herald fresh perspectives to develop high-voltage cathode materials for sodium-ion batteries.

Constructing a Size-Controllable Spherical P2-Type Layered Oxides Cathode That Achieves Practicable Sodium-Ion Batteries.

P2-type layered metal oxides are regarded as promising cathode materials for sodium-ion batteries due to their high voltage platform and rapid Na+ diffusion kinetics. However, limited capacity and unfavorable cycling stability resulting from inevitable phase transformation and detrimental structure collapse hinder their future application. Herein, based on P2-type Na0.67Ni0.18Mn0.67Cu0.1Zn0.05O2, we synthesized a series of secondary spherical morphology cathodes with different radii derived from controlling precursors prepared by a coprecipitation method, which can be promoted to large-scale production. Consequently, the synthesized materials possessed a high tap density of 1.52 g cm-3 and a compacted density of 3.2 g cm-3. The half cells exhibited a specific capacity of 111.8 mAh g-1 at a current density of 0.1 C as well as an 82.64% capacity retention with a high initial capacity of 85.80 mAh g-1 after 1000 cycles under a rate of 5 C. Notably, in situ X-ray diffraction revealed a reversible P2-OP4 phase transition and displayed a tiny volume change of 6.96% during the charge/discharge process, indicating an outstanding cycling stability of the modified cathode. Commendably, the cylindrical cell achieved a capacity of 4.7 Ah with almost no change during 1000 cycles at 2 C, suggesting excellent potential for future applications.

Attention towards chemistry agnostic and explainable battery lifetime prediction

Predicting and monitoring battery life early and across chemistries is a significant challenge due to the plethora of degradation paths, form factors, and electrochemical testing protocols. Existing models typically translate poorly across different electrode, electrolyte, and additive materials, mostly require a fixed number of cycles, and are limited to a single discharge protocol. Here, an attention-based recurrent algorithm for neural analysis (ARCANA) architecture is developed and trained on an ultra-large, proprietary dataset from BASF and a large Li-ion dataset gathered from literature across the globe. ARCANA generalizes well across this diverse set of chemistries, electrolyte formulations, battery designs, and cycling protocols and thus allows for an extraction of data-driven knowledge of the degradation mechanisms. The model’s adaptability is further demonstrated through fine-tuning on Na-ion batteries. ARCANA advances the frontier of large-scale time series models in analytical chemistry beyond textual data and holds the potential to significantly accelerate discovery-oriented battery research endeavors.

A Physics-based Model Assisted by Machine-Learning for Sodium-ion Batteries with both Liquid and Solid Electrolytes

Abstract In the absence of experimental data of a fully developed hierarchical 3D sodium solid state batteries, we developed an improved continuum model by relying on Machine Learning-assisted parameter fitting to uncover the intrinsic material properties that can be transferred into different battery models. The electrochemical system simulated has sodium metal P2-type Na2/3[Ni1/3Fe1/12Mn7/12]O2 (NNFMO) as the cathode, paired with two types of electrolytes have been modeled viz, the organic liquid electrolyte and a solid polymer electrolyte. We implemented a 1D continuum model in COMSOL to suit both liquid and solid electrolytes, then used a Gaussian Process Regressor to fit and evaluate the electrochemical parameters in both battery systems. To enhance the generalizability of our model, the liquid cell and solid cell models share the same OCV input for the cathode materials. The resulting parameters are well aligned with their physical meaning and literature values. The continuum model is then used to understand the effect of increasing the thickness of the cathode and current density by analysing the cathode utilization, and the overpotentials arising from transport and charge transfer. This 1D model and the parameter set are ready to be used in a 3D battery architecture design.

Solid-Solution Reaction and Ultrasmall Volume Change in High-Entropy P2-type Layered Oxide Cathode for All-Climate Sodium-Ion Batteries

Solid-Solution Reaction and Ultrasmall Volume Change in High-Entropy P2-type Layered Oxide Cathode for All-Climate Sodium-Ion Batteries

Air Corrosion of Layered Cathode Materials for Sodium-Ion Batteries: Cation Mixing and a Practical Suppression Strategy

Air Corrosion of Layered Cathode Materials for Sodium-Ion Batteries: Cation Mixing and a Practical Suppression Strategy

Controllable Preparation and Sodium Storage Properties of Sb2Te3–Te Heterojunction

Antimony-based materials possess high theoretical capacities and suitable potential, which could be promising anode materials for sodium-ion batteries (SIB). However, poor stabilities and sluggish kinetics are drawbacks. Building heterojunction is an ideal method to solve these issues. Its unique structure develops internal electric fields spontaneously to boost the charge transport and relieve stress. Nevertheless, the controllable preparation of face-to-face (2D) heterojunctions is still hard-pressed. Herein, Sb2Te3–Te nanoheterojunctions, which consist of two-dimensional Sb2Te3 nanoblades attached to a one-dimensional Te nanorod, are fabricated through a two-step solvothermal method. Among that, the density of nanoblades is adjustable through the engineering feed ratio. When employed as anodes for SIBs, Sb2Te3–Te nanoheterojunctions display a reversible capacity of 463.2[Formula: see text]mAh[Formula: see text]g[Formula: see text] at 100[Formula: see text]mA[Formula: see text]g[Formula: see text]. Even a capacity of 305.5[Formula: see text]mAh[Formula: see text]g[Formula: see text] remains after 1000 cycles under a high current of 1.5[Formula: see text]A[Formula: see text]g[Formula: see text]. Moreover, the density functional theory (DFT) calculations also identify the high conductivity of heterojunction. This work offers an effective way to design the structures and properties of heterojunctions, further expanding their application range.

Scalable Synthesis of Layered Bismuth Germanate (Bi12GeO20) for Supercapacitors and Sodium ion Battery Applications

Scalable Synthesis of Layered Bismuth Germanate (Bi12GeO20) for Supercapacitors and Sodium ion Battery Applications

High stability of Cu-doped O3-type NaNi1/3Fe1/3Mn1/3O2 cathode material for sodium-ion battery

High stability of Cu-doped O3-type NaNi1/3Fe1/3Mn1/3O2 cathode material for sodium-ion battery

Mixed polyanionic NaFe1.6V0.4(PO4)(SO4)2@CNT cathode for sodium-ion batteries: Electrochemical diffusion kinetics and distribution of relaxation time analysis at different temperatures

We report the electrochemical sodium-ion kinetics and distribution of relaxation time (DRT) analysis of a newly designed mixed polyanionic NaFe1.6V0.4(PO4)(SO4)2@CNT composite as a cathode. The specific capacity of 104 mAhg−1 is observed at 0.1 C with the average working voltage of ∼3 V. Intriguingly, a remarkable rate capability and reversibility are demonstrated up to very high current rate of 25 C. The long cycling test up to 10 C shows high capacity retention even after 2000 cycles. The detailed analysis of galvanostatic intermittent titration technique (GITT) and cyclic voltammetry (CV) data reveal the diffusion coefficient of 10−8–10−11 cm2s−1. We find excellent stability in the thermal testing between 25–55 °C temperatures and 80% capacity retention up to 100 cycles at 5 C. Further, we analyze the individual electrochemical processes in the time domain using the novel DRT technique at different temperatures. The ex-situ investigation shows the stable and reversible structure, morphology and electronic states of the long cycled cathode material. More importantly, we demonstrate relatively high specific energy of ≈155 Wh kg−1 (considering the total active material loading of both the electrodes) at 0.2 C for full cell battery having excellent rate capability up to 10 C and long cyclic stability at 1 C.

Pb nanospheres encapsulated in metal–organic frameworks-derived porous carbon as anode for high-performance sodium-ion batteries

Alloying-type anode materials are considered promising candidates for sodium-ion batteries (SIBs) due to their high theoretical capacities. However, their application is limited by the severe capacity decay stemming from dramatic volume changes during Na+ insertion/extraction processes. Here, Pb nanospheres encapsulated in a carbon skeleton (Pb@C) were successfully synthesized via a facile metal–organic frameworks (MOFs)-derived method and used as anodes for SIBs. The nanosized Pb particles are uniformly incorporated into the porous carbon framework, effectively mitigating volume changes and enhancing Na+ ion transport during discharging/charging. Benefiting from this unique architecture, a reversible capacity of 334.2 mAh g−1 at 2 A g−1 is achieved after 6000 cycles corresponding to an impressive 88.2 % capacity retention and a minimal capacity loss of 0.00748 % per cycle. Furthermore, a high-performance full sodium-ion battery of Pb@C//NVPF was constructed, demonstrating a high energy density of 291 Wh kg−1 and power density of 175 W kg−1. This facile MOFs-derived method offers insights into the design of high-capacity alloy-type anode materials using Pb sources, opening up new possibilities for innovative approaches to Pb recycling and pollution prevention.

Modulating Valence Electrons and Na Occupancy in Layered Cathodes for High-Performance Na-Ion Batteries.

Na-ion batteries (NIBs) hold promise as a leading option for large-scale energy storage. However, their development faces challenges due to the lack of high-performance cathode materials. P2-type layered oxides are seen as potential cathode materials for NIBs due to higher structure stability, yet their commercialization is hindered by limited capacity and subpar phase transitions during Na extraction and insertion at high voltages. In this study, we introduce a new P2-type cathode material, Na0.76Ni0.23Li0.1Ti0.02Mn0.65O1.998F0.02 (NLTMOF), synthesized with ternary Li/Ti/F substitution. This modification of ternary Li/Ti/F substitution significantly tailors the electronic structures, increasing the number of valence electrons near the Fermi energy level. This facilitates the electronic conductivity and their involvement in charge compensation, thereby enhancing reversible capacity. Additionally, ternary doping synergistically adjusts the Na occupancy at the Na layer for favorable Na extraction without P2-O2 phase transitions even under a high voltage of 4.4 V, boosting cycling stability. As a result, NLTMOF demonstrates a reversible capacity of 110.0 and 132.2 mAh g-1 at 2-4.2 and 2-4.4 V, respectively, and maintains greatly enhanced cycling stability over long cycles. This study sheds light on the design of transition metal oxides for advanced cathode materials through the modulation of electronic structure and Na occupancy in cathode materials, thus promoting the development of NIBs.

Performance of CuP2 Negative Electrode for Na‐Ion Batteries with CNTs As Stabilizer

AbstractTransition metal phosphides (TMPs) are promising anode materials for sodium ion battery, thanks to their high theoretical specific capacities. Nevertheless, they suffer from large volume change and from poor conductivity during prolonged cycling. Here we systematically investigate the role of different kinds of single/multi‐wall carbon nanotubes (SWCNTs/MWCNTs) as additives in order to stabilize copper phosphide particles (CuP2) as anode materials in sodium ion batteries (SIBs). All composites show enhancement in the overall capacity and cycling stability compared to the pristine CuP2 due to the well‐connected CNTs on and between the CuP2 particles. At a high currency density of 1 A g−1, CuP2@SWCNTs composite with 13 wt.% SWCNTs can deliver a specific capacity over 400 mAh g−1 for more than 60 cycles, much better than conventional hard carbon materials. The CNTs enhance the conductivity and reduce capacity loss caused by the volume variation of CuP2 based electrode materials. Post‐mortem analysis by scanning electron microscopy depicts a possible battery failure mechanism, whereby the solid electrolyte interface exists in the form of nanospheres distributing at the surface of the electrode. During the repeated cycling (volume change), more fractures and cracks occur resulting in continuous interfacial reactions and consumption of sodium and electrolyte.