Rechargeable Na-ion Batteries Research Articles

Copper and nickel hexacyanoferrates/carbon nanotube nanocomposites thin films as high-performance light cathode materials for aqueous sodium-ion batteries

Aqueous rechargeable Na-ion batteries are gaining popularity as an attractive alternative for energy storage systems due to their low cost, wide range of raw material sources, non-flammability, and ultrahigh ionic conductivity. Currently, Because of their three-dimensional open structure, high specific capacity, and inexpensive cost, Prussian blue analogues are being investigated as electrode materials for electrochemistry. In this work, we present an innovative strategy to create novel two-component nanoarchitected thin films that exhibit exceptional performance as cathodes in aqueous sodium-ion batteries (SIBs). By leveraging the versatility of the liquid-liquid interfacial method, we have prepared two distinct transparent nanocomposite films composed of carbon nanotubes and either copper or nickel hexacyanoferrate nanoparticles. The results show that the NiHCF/CNT and CuHCF/CNT deliver a high specific capacity of 152 mA h g−1 and 135 mA h g−1, respectively, at a high current density of 1 A g−1. Moreover, the cells (rGO//NiHCF and rGO//CuHCF) show that the energy density of the battery can reach up to 7.75 Wh kg−1 at a power density of 27.92 W kg−1 for rGO//NiHCF/CNT, while rGO//CuHCF/CNT showed an energy density of 3.67 Wh kg−1 at a power density of 13.21 W kg−1. The results demonstrate that NiHCF/CNT and CuHCF/CNT nanocomposite films provide new insight into the design of high-performance PBA cathodes.

Operando Stress Evolution in Hard Carbon Anodes – Insight into the Mechanical Degradation Induced Failure Mode in Rechargeable Sodium Ion Batteries

Microstructural instabilities in electrodes arising from cycling induced stress is a primary failure mode in rechargeable batteries. Therefore, a quantitative knowledge of the cycling induced stress evolution in rechargeable battery electrodes is important for understanding the electrode microstructural instabilities during cycling that can potentially inform the electrode design to prolong battery cycle life. The cycling induced stress in electrodes typically arises from the volume changes associated with insertion/extraction of the electroactive species in the electrode matrix. For example, operando measurement of lithiation-delithiation induced stress in graphite electrodes that typically show 10% volume change has previously resulted in useful information that correlates well with the lithiation-delithiation mechanism in graphite anodes1. The size of the shuttling-electroactive species can be taken as an indicator of the cycling induced stress magnitude that drives the electrode microstructural instabilities. In this regard, quantification of the cycling induced stress in rechargeable Na-ion battery electrodes is warranted for understanding mechanical degradation induced failure modes owing to the larger size of the electroactive species, i.e., Na ions (vs. Li-ion).Hard carbons as potential anodes in rechargeable sodium ion batteries has gained considerable attention in the recent past due to their superior Na-ion storage capability (vs. graphite that is a canonical anode in rechargeable lithium-ion batteries). However, hard carbon anodes typically show significant capacity fade that can potentially arise from cycling induced mechanical degradation of the anodes. Operando stress measurements coupled with comprehensive electrode microstructural characterization will provide valuable insights in this context. Here we report on the operando stress evolution in hard carbon anodes in rechargeable sodium ion batteries as probed by Multiple Optical-beam Sensing (MOS) technique that basically involves monitoring the spacings among a group of laser spot (Fig. 1). Preliminary measurements have shown that the stress correlates with the potential with a maximum around 12 MPa in compression during sodiation and tensile stress of ~ 2MPa during desodiation. Operando stress measurements are performed in hard carbon anodes in two different electrode configurations – typical composite anodes (with binder and conductive agents) and hard carbon thin film anodes (without binder and conductive agents). The thin film configuration is considered to evaluate intrinsic stress response in hard carbon anodes in absence of any secondary phase. A comparison of operando stress response in these two types of hard carbon anodes along with comprehensive electrode microstructural characterization will be presented. Additionally, attempts will be made to shed light on the current debate in the mechanism of sodium storage in hard carbon anodes by comparing operando stress response of hard carbons from multiple sources along with their structural characterization (Raman, XPS, surface area etc.). V. A. Sethuraman, N. Van Winkle, D. P. Abraham, A. F. Bower, and P. R. Guduru, Journal of Power Sources, 206, 334–342 (2012). Figure 1

Construction of metal-organic framework-derived Al-doped Na 3V 2(PO 4) 3 cathode materials toward high-performance rechargeable Na-ion battery

Construction of metal-organic framework-derived Al-doped Na ₃V ₂(PO ₄) ₃ cathode materials toward high-performance rechargeable Na-ion battery

First principles study of a triazine-based covalent organic framework as a high-capacity anode material for Na/K-ion batteries.

The rational design of high-performance anode materials is crucial for the development of rechargeable Na-ion batteries (NIBs) and K-ion batteries (KIBs). In this study, based on density functional theory (DFT) calculations, we have systematically investigated the possibility of a bilayer triazine-based covalent organic framework (bilayer TCOF) as an anode for NIBs and KIBs. The calculation of the electronic band structure shows that the bilayer TCOF is a direct band gap semiconductor with a band gap of 2.01 eV. After the adsorption of Na/K at the most favorable sites, the bilayer TCOF transitions from a semiconductor to a metal state, guaranteeing good electronic conductivity. The low diffusion barriers of the bilayer TCOF are 0.45 and 0.26 eV, respectively, indicating a fast diffusion rate of Na/K ions. In addition, the bilayer TCOF has a theoretical storage capacity of up to 628 mA h g-1. Finally, it is found that the average voltage of the bilayer TCOF for NIBs and KIBs is 0.53 and 0.48 V, respectively. Based on these results, we can conclude that the bilayer TCOF may be a suitable anode material for NIBs and KIBs.

An ultrafast Na-ion battery chemistry through coupling sustainable organic electrodes with modulated aqueous electrolytes

Regulating the solvation sheath reorganization kinetics through electrolyte engineering can facilitate an unprecedented battery chemistry.

Construction of metal–organic framework-derived Al-doped Na 3V 2(PO 4) 3 cathode materials for high-performance rechargeable Na-ion batteries

Construction of metal–organic framework-derived Al-doped Na ₃V ₂(PO ₄) ₃ cathode materials for high-performance rechargeable Na-ion batteries

Monolayer TiSiP as a high-performance anode for Na-ion batteries

Exploring anode materials with overall excellent performance remains a great challenge for rechargeable Na-ion battery technologies. Herein, we have identified that monolayer TiSiP is just such a prospective anode candidate via first-principles calculations. It is showed to be dynamically, thermally, mechanically, and energetically stable, which provides feasibility for experimental realization. The Na diffusion on the its surface is proved to be ultrafast, with a migration energy barrier as low as 73 meV. Electronic structure confirms that the pristine system undergoes a transition from the semiconductor to metal during the whole sodiation process, which is a significant advantage to the electrode conductivity. More excitingly, monolayer TiSiP can accommodate up to double-sided five-layer adatoms, resulting in an ultrahigh theoretical capacity of 1176 mA h g−1 and a low average open-circuit voltage of 0.195 V. Moreover, the maximally sodiated electrode monolayer yields rather small in-plane lattice expansion of only 1.40%, which ensures reversible deformation and excellent cycling stability as further corroborated by structural relaxation and ab initio molecular dynamics simulation. Overall, all of these results point to the potential that monolayer TiSiP can serve as a promising anode candidate for application in high-performance low-cost Na-ion batteries.

Enhanced conversion reaction of Na-Cu-PO3 via amorpholization and carbon-coating for large Na storage

Conversion-type cathodes have a higher theoretical capacity compared to intercalation-type cathodes due to the use of more transition metal cations. However, their sluggish kinetics and low operation voltage hinder their practical application in the industry, resulting in low specific capacity. To address these issues, we prepare an amorphous carbon-coated Cu(PO3)2 nanocomposite, and evaluate its electrochemical performance under rechargeable Na-ion battery system. At a current density of 24 mA/g, it achieves a large specific capacity of ∼232 mAh/g with an average operation voltage of ∼2.0 V (vs. Na+/Na). Furthermore, the amorphous carbon-coated Cu(PO3)2 nanocomposite exhibits a cycle retention of ∼90% compared to the initial capacity after 100 cycles. In contrast, bare Cu(PO3)2 shows poor electrochemical performance under the same conditions. Various experimental measurements have demonstrated that the amorphous carbon-coated Cu(PO3)2 nanocomposite exhibits a reversible and smooth conversion reaction of Cu(PO3)2 phase in the rechargeable Na-ion battery system.

Improving the Electrochemical Performance of Fluorinated Carbons by Solvent Co–Intercalation for Rechargeable Na–Ion Battery Cathodes

CF x deliver the ultra-high theoretical specific capacity. Nevertheless, its solvent co-intercalation for rechargeable Na–ion battery cathodes has lacked investigation. Here, we explored the co–intercalation behaviour with 1 M NaPF6 in PC or FEC for various CF x and found that 1 M NaPF6 in FEC is conducive to solvent co–intercalation in the extended discharge voltage window to 1.0 V. Among them, F-CF0.88 cathodes present a discharge-specific capacity for the first time of 1094 mAh g−1, which keeps a stable rechargeable specific capacity of 344 mAh g−1. This improved rechargeable behaviour is connected with the solvent co-intercalation. And the reason is that the solvation energy of fluoroethylene carbonate (FEC) is larger and easier to embed. Our study offers new ideas and a deep understanding of solvent co-intercalation of CF x as Na–ion rechargeable battery.

Self-assembled nanostructures of PDI-bolaamphiphiles as anode materials for advanced rechargeable Na-ion batteries

Organic electrode materials become more attractive for sodium-ion batteries (NIBs) owing to their structural flexibility, and eco-friendly nature. However, currently, they were confronted with less capacity and poor cycle stability. Herein, we synthesize various nanoarchitectures from PDI-bolaamphiphiles by employing a simple self-assembly strategy and exploited them as anode materials for NIBs. The simple structural mutation of amino acid side chain had shown a significant impact on morphology and performance of the battery. The NF (Nanofiber) electrode delivered a high average specific capacity of 271 mAh g−1 at a current density of 50 mA g−1 and displayed a remarkable rate performance and delivered exceptional capacity retention of 97% after 200 cycles. In addition, it was also surpassed the majority of organic anodes by retaining a capacity of 85%, after 1000 charge-discharge cycles, at a high current density of 1 A g−1. The mechanism of sodiation and desodiation during the charge-discharge process was revealed by qualitative and quantitative analysis. Altogether, the nanofiber structure of NF electrode enhances the electrochemical properties by accelerating sodication/de-sodication potentials and the carboxylic group reduces its solubility in the organic electrolyte, ensuring it a potential material for greener, sustainable, highly stable organic anode material for NIBs.

Hydrothermally Synthesized Fluorine Added O3-NaFe1-xMgxO2 Cathodes for Sodium Ion Batteries

The development and study of Na ion batteries are expanding. This study employs the hydrothermal technique to produce single-phase, well-crystallized, fluorine-added O3-type NaFe1-xMgxO2. Using XRD, FESEM, and HRTEM, the sample’s phase structure and morphological information were characterized. Initially, without adding fluorine the electrode suffers from poor stability at high voltage ranges and also during long-term cycling. So, fluorine was added to the structure and the electrochemical performance of the material was greatly increased. The electrochemical performance of O3-type positive electrode materials for rechargeable Na ion batteries is evaluated. The capacity of fluorine-added O3-type NaFe1-xMgxO2 is approximately 163 mAh g−1 (50 mA g−1). Adding fluorine to the host structure increases the stability of the electrode, leading to improved electrochemical performance during long-term cycling. The electrochemical results indicate that fluorine-added O3-type NaFe1-xMgxO2 cathode material for cost-effective and environmentally friendly sodium-ion batteries is promising. Fluorine-based electrodes will be a future for Na ion energy storage devices

Carbon confined GeO2 hollow spheres for stable rechargeable Na ion batteries.

Germanium (Ge) based nanomaterials are regarded as promising high-capacity anode materials for Na ion batteries, but suffer fast capacity fading problems caused by the alloying/de-alloying reactions of Na-Ge. Herein, we report a new method for preparing highly dispersed GeO2 by using molecular-level ionic liquids (ILs) as carbon sources. In the obtained GeO2@C composite material, GeO2 exhibits hollow spherical morphology and is uniformly distributed in the carbon matrix. The as-prepared GeO2@C exhibits improved Na ion storage performances including high reversible capacity (577 mA h g-1 at 0.1C), rate property (270 mA h g-1 at 3C), and high capacity retention (82.3% after 500 cycles). The improved electrochemical performance could be attributed to the unique nanostructure of GeO2@C, the synergistic effect between GeO2 hollow spheres and the carbon matrix ensures the anode material effectively alleviates the volume expansion and the particle agglomeration problems.

A zero-strain Na-deficient NASICON-type Na2.8Mn0.4V1.0Ti0.6(PO4)3 cathode for wide-temperature rechargeable Na-ion batteries

Na superionic conductor (NASICON) type cathode materials with high structural stability and fast Na+ diffusion have been considered as high-power candidates for the exploration of Na-ion batteries.

Carboxylate-derived conductive, sodium-ion storable surface of Prussian Blue with a stable cathode-electrolyte interface

Considering the high binding affinity between carboxylate ligands (−O–CO) and alkaline Na ions, Prussian blue (PB) with a carboxylate-derived conductive, Na-ion storable surface is developed as a cathode material for Na-ion rechargeable batteries. Here, citric acid (CA) (C6H8O7) is introduced as a carboxylate source because, in a neutral aqueous solution, it loses two H ions of each molecule to reach an acid-base equilibrium and is stabilized in a chemical form with two −O–CO ligands that are accompanied by two delocalized electrons. Consequently, these functional groups newly formed from CA remain on the surfaces of PB particles even when PB is co-precipitated using CA and sodium citrate as dual chelating agents. Specifically, they strongly bind to high-spin Fe (FeHS) ions on the PB surface, providing additional active sites for Na-ion storage via a quasi-reversible, surface redox process (i.e., FeHS–R–C–O– ↔ FeHS–R–C–O–Na) in the low-voltage region close to 3.0 V (vs. Na+/Na). During charge/discharge cycling, inserted Na ions prefer to be stored in the activated surface sites instead of being used to produce unstable by-products by electrolyte decomposition, which resultantly inhibits the thick growth of cathode-electrolyte interface (CEI) layers on the PB particles. As a result, 2 wt% CA-assisted PB exhibits high first discharge capacity (∼110 mA h g−1) and low average capacity decay rate (−0.39 mA h g−1/cycle) at a current density of 0.2 C.

Sodium storage behavior and long cycle stability of boron-doped carbon nanofibers for sodium-ion battery anodes

A double heteroatom doping strategy is proposed to synthesize boron- and nitrogen-doped heteroatom carbon nanofibers (BNC NFs) as anode materials for sodium-ion batteries (SIBs). The specific capacity and rate performance of the BNC NF anode are higher than those of the NC NF anode. Particularly, the composite containing 5 wt% boric acid provides the highest reversible capacity of 249 mAh g−1 at a current density of 0.02 A g−1 and excellent cyclic stability of 144 mAh g−1 at 2 A g−1 after 3000 cycles. The excellent cyclic performance of the BNC NFs can be attributed to the defect-rich nanostructure derived by optimally doping boron under annealing, which is conducive to accelerating ion transport and introducing additional Na-ion storage active sites. The excellent capacity and long cycle stability of the full cell SIBs comprising the optimized BNC NFs anode and Na3V2(PO4)3 cathode suggest the promising potential of B-doped C NFs as anodes for rechargeable Na-ion batteries.

Design of Perovskite-Type Fluorides Cathodes for Na-ion Batteries: Correlation between Structure and Transport

Transition metal-based sodium fluoro-perovskite of general formula NaMF3 (M = Fe, Mn, and Co) were investigated as cathode materials for rechargeable Na-ion batteries. Preliminary results indicated Na-ion reversible intercalation but highlighted the need to find optimization strategies to improve conductivity and to modulate the operating voltages within experimentally accessible electrolytes’ stability windows, in order to fully exploit their potential as high-voltage cathodes. In this study, we combined experimental and computational techniques to investigate structures, defects, and intercalation properties of the NaFe1-xMnxF3 and NaCo1-xMnxF3 systems. Through the use of a simple solvothermal synthesis, we demonstrated the possibility to modulate the sample’s morphology in order to obtain fine and dispersed powder samples. The structural results indicated the formations of two solid solutions with a perovskite structure over the entire compositional range investigated. Atomistic simulations suggested that Na-ion diffusion in these systems was characterized by relatively high migration barriers and it was likely to follow three-dimensional paths, thus limiting the effect of anti-site defects. The correlation between structural and computational data highlighted the possibility to modulate both ionic and electronic conductivity as a function of the composition.

Eldfellite-structured NaCr(SO4)2: a potential anode for rechargeable Na-ion and Li-ion batteries.

Recent global concerns over continuously increasing air pollution and the related health risks due to automobile exhaust have shifted our attention towards green transportation. Recent decades have witnessed a revolution in portable energy-storage systems, mainly lithium-based energy-storage devices. However, the uneven distribution of global lithium reserves and its scarcity lead to huge price differences and geopolitical imbalances, and hence the research in energy-storage materials has shifted towards the development of cost-effective, abundant electrode materials. Here, NaCr(SO4)2, a transition metal-based polyanionic layered material with low cost and high stability during the charge/discharge process vs. Na, operating on the basis of the Cr3+/2+ redox couple, is presented. The test materials were characterized by techniques like XRD, FTIR, SEM, UV, XPS, TGA-DTA, and a detailed electrochemical analysis of the charge/discharge capacity of the materials is presented here. Here, the findings provide insights towards achieving a Cr3+/Cr2+ redox-couple-based sodium-ion battery with a specific capacity of 75 mA h g-1 and 150 mA h g-1 at operating voltages of 0.95 V vs. Na and 1.05 V vs. Li, respectively, with 100% coulombic efficiency. Cr2+ is a very special oxidation of Cr that cannot be obtained easily and CrTa2O6 is the only known oxide where Cr exists in the 2+ state. Here, a shift in the redox energy of the Cr3+/2+ couple was obtained due to its bonding with (SO4)2- polyanions in eldfellite that made the accessibility of Cr3+/2+ possible, resulting in the superior intercalation/deintercalation of Na and Li and the superior energy-storage capacity of the NaCr(SO4)2vs. Na/Li cell.

NASICON-structured Na3Fe2PO4(SO4)2: a potential cathode material for rechargeable sodium-ion batteries.

The cost-effective and abundant availability of sodium offers an opportunity for rechargeable Na-ion batteries as an ideal replacement for rechargeable Li-ion batteries. However, the larger size and strong Na+-Na+ interaction create multidimensional phase instability and transformation problems, especially in layer-structured NaxMO2 (Mn, Co, Fe, and Ni) that inhibit the direct transformation of rechargeable Li-ion battery technology to Na-ion batteries. However, framework structures offer superior structural stability due to the interconnection of polyanions or polyhedra forming cationic octahedra. Sodium superionic conductor (NASICON)-type structures are well known for their superior Na+ ion transport and are identified as intercalative hosts as electrodes for rechargeable Na-ion batteries. Here, we report the synthesis of Na3Fe2PO4(SO4)2 in a NASICON framework structure and its investigation as a cathode in a Na/Na3Fe2PO4(SO4)2 cell working on the Fe3+/Fe2+ redox couple. The cell provides a single-phase reaction having a capacity approaching 70 mA h g-1 at 0.1 C after 50 cycles in the voltage range of 2 to 4.2 V, with a columbic efficiency approaching 100%. The large availability of Na and Fe with the stable redox and charge/discharge performance of NASICON-type Na3Fe2PO4(SO4)2 make it a possible cathode candidate for next-generation rechargeable sodium-ion batteries.

Self-Assembled Nanostructures of Pdi-Bolaamphiphiles as Anode Materials for Advanced Rechargeable Na-Ion Batteries

Self-Assembled Nanostructures of Pdi-Bolaamphiphiles as Anode Materials for Advanced Rechargeable Na-Ion Batteries

Na+ diffusion mechanism and transition metal substitution in tunnel-type manganese-based oxides for Na-ion rechargeable batteries

Structural, computational and electrochemical investigations are combined to study the intercalation properties of tunnel-type Na0.44MnO2 and Cu-substituted Na0.44MnO2.