Search

Mixing polyanion cathode materials are promising candidates for the development of next-generation batteries, owing to their structural robustness and low-volume changes, yet low conductivity of polyanion hinders their practical capacity. Herein, the anion-site regulation is proposed to elevate the electrode kinetics and properties of polyanionic cathode. Multivalent anion P2O74− is selected to substitute the PO43− in Na3V2(PO4)3 (NVP) lattice and regulate the ratio of polyanion groups to prepare Na3+xV2(PO4)3−x(P2O7)x (NVPPx, 0 ≤ x ≤ 0.15) materials. The optimal Na3.1V2(PO4)2.9(P2O7)0.1 (NVPP0.1) material can deliver remarkably elevated specific capacity (104 mAh g−1 at 0.1 C, 60 mAh g−1 at 20 C, respectively), which is higher than those of NVP. Moreover, NVPP0.1 exhibits outstanding cyclic stability (91% capacity retention after 300 cycles at 1 C). Experimental analyses reveal that the regulation of anions improves the structure stability, increases the active Na occupancy in the lattice and accelerates the Na+ migration kinetics. The strategy of anion-site regulation provides the researchers a reference for the design of new high-performance polyanionic materials.

For the first time, we have devised an all-solid-state hybrid Li/Na-ion battery, which offers a new and profound way to develop high-safety and low-cost hybrid batteries.

Although ether-based electrolytes have been extensively applied in anode evaluation of batteries, anodic instability arising from solvent oxidability is always a tremendous obstacle to matching with high-voltage cathodes. Herein, by rational design for solvation configuration, the fully coordinated ether-based electrolyte with strong resistance against oxidation is reported, which remains anodically stable with high-voltage Na3 V2 (PO4 )2 O2 F (NVPF) cathode under 4.5 V (versus Na+ /Na) protected by an effective interphase. The assembled graphite//NVPF full cells display superior rate performance and unprecedented cycling stability. Beyond that, the constructed full cells coupling the high-voltage NVPF cathode with hard carbon anode exhibit outstanding electrochemical performances in terms of high average output voltage up to 3.72 V, long-term cycle life (such as 95 % capacity retention after 700 cycles) and high energy density (247 Wh kg-1 ). In short, the optimized ether-based electrolyte enriches systematic options, the ability to maintain oxidative stability and compatibility with various anodes, exhibiting attractive prospects for application.

In recent years, sodium-ion batteries (SIBs) have been considered as one of the most promising alternatives to lithium-ion batteries (LIBs). Here, a new Na-super-ionic conductor (NASICON) cathode material NaFe2PO4(SO4)2 is successfully prepared through solid state method for SIBs. While the poor electronic conductivity of iron-based materials results in its poor rate and cycle performance. Then the electrochemical is effectively promoting via Ca2+ doping. Na0.84Ca0.08Fe2PO4(SO4)2 have achieved considerable electrochemical properties. The first discharge specific capacity is 121.6 mA h g−1 at 25 mA g−1 with the voltage platform (∼3.1 V) corresponding to Fe2+/3+. After 100 cycles, the capacity retention is 55.1 %. The excellent electrochemical performance is caused by some Na+ is substituted by Ca2+ and leading to the fast sodium kinetics, which is well proved by the powder X-ray diffraction pattern and well corresponding to the galvanostatic intermittent titration technique and cyclic voltammetry testing result (the diffusivity values are around at 10−12 cm2 s−1).

Flexible power sources featuring high-performance, prominent flexibility and raised safety have received mounting attention in the area of wearable electronic devices. However, many great challenges remain to be overcome, notably the design and fabrication of flexible electrodes with excellent electrochemical performance and matching them with safe and reliable electrolytes. Herein, a facile approach for preparing flexible electrodes, which employs carbon cloth derived from commercial cotton cloth as the substrate of cathode and a flexible anode, is proposed and investigated. The promising cathode (NVPOF@FCC) with high conductivity and outstanding flexibility is prepared by efficiently coating Na3V2(PO4)2O2F (NVPOF) on flexible carbon cloth (FCC), which exhibits remarkable electrochemical performance and the significantly improved reaction kinetics. More importantly, a novel flexible quasi-solid-state sodium-ion full battery (QSFB) is feasibly assembled by sandwiching a P(VDF-HFP)-NaClO4 gel-polymer electrolyte film between the advanced NVPOF@FCC cathode and FCC anode. And the QSFBs are further evaluated in flexible pouch cells, which not only demonstrates excellent energy-storage performance in aspect of great cycling stability and high-rate capability, but also impressive flexibility and safety. This work offers a feasible and effective strategy for the design of flexible electrodes, paving the way for the progression of practical and sustainable flexible batteries.

As a cathode for sodium‐ion batteries (SIBs), Na3V2(PO4)2F3 (NVPF) with 3D open framework is a promising candidate due to its high working voltage and large theoretical capacity. However, the severe capacity degradation and poor rate capability hinder its practical applications. The present study demonstrated the optimization of Na‐storage performance of NVPF via delicate lattice modulation. Aliovalent substitution of V3+ at Na+ in NVPF induces the generation of electronic defects and expansion of Na+‐migration channels, resulting in the enhancement in electronic conductivity and acceleration of Na+‐migration kinetics. It is disclosed that the formed stronger NaO bonds with high ionicity than VO bonds lead to the significant increase in structural stability and ionicity in the Na+‐substituted NVPF (NVPF‐Nax). The aforementioned effects of Na+ substitution achieve the unprecedented electrochemical performance in the optimized Na3.14V1.93Na0.07(PO4)2F3 (NVPF‐Na0.07). As a result, NVPF‐Na0.07 delivers a high‐rate capability (77.5 mAh g−1 at 20 C) and ultralong cycle life (only 0.027% capacity decay per cycle over 1000 cycles at 10 C). Sodium‐ion full cells are designed using NVPF‐Na0.07 as cathode and Se@reduced graphene oxide as anode. The full cells exhibit excellent wide‐temperature electrochemical performance from −25 to 25°C with an outstanding rate capability (96.3 mAh g−1 at 20 C). Furthermore, it delivered an excellent cycling performance over 300 cycles with a capacity retention exceeding 90% at 0.5 C under different temperatures. This study demonstrates a feasible strategy for the development of advanced cathode materials with excellent electrochemical properties to achieve high‐efficiency energy storage.

Sodium-ion batteries (SIBs) are prominently used for stationary energy storage due to the abundant resources and low cost of Na. The development of high-performance cathodes for SIBs will be a favorable choice for competing with the market-dominant lithium-ion batteries. Among the various cathodes, Na3V2(PO4)2O2−2xF1+2x (0 ≤ x ≤ 1) materials have become a preferred choice due to their superior structural stability, fast ion transport and high operating potential. Herein, a series of materials with various ratios of F− and O2− (F/O) are prepared via a high temperature solid-state method, and the tuning mechanism of different F/O ratios is studied in detail by analyzing the structural evolution, electrochemical performance and reaction kinetics of materials. The optimal F/O ratio material Na3V2(PO4)2O0.6F2.4 (x = 0.7) exhibits a favorable rate and cycling performance. The capacity at 20C is equivalent to that of the x = 0 material at 5C, and each cycle decay is 0.040% after 200 cycles at 0.5C. Moreover, the optimized F/O ratio material (x = 0.7) also demonstrates excellent reaction kinetics, and the Na apparent diffusion coefficient (Dapp,Na) for the high potential region is about 10−10–10−12 cm2 s−1. A systematic research of dual anion substitution in phosphates will be useful for the structural design and performance improvement of other cathode materials in SIBs.

The reuse of waste biomass has received more and more attention in recent years due to resource and environmental problems. The development of green, environmentally friendly and cost-effective electrode materials for lithium-ion batteries (LIBs) and sodium-ion batteries (SIBs) is currently the focus of research as key electrochemical energy storage systems. Herein, a facile strategy is adopted to prepare 3D hierarchical porous carbon anodes for LIBs/SIBs by taking advantage of waste crab shells and iron p-toluenesulfonate. The results show that the reversible specific capacity of the prepared anode could reach 703.2 mAh g−1 in LIBs and 283.2 mAh g−1 in SIBs when the current density is 0.05 A g−1. In addition, the contributions of pseudocapacitance, the kinetic characteristics and the storage mechanisms of lithium/sodium ions are investigated through cyclic voltammetry (CV) and galvanostatic intermittent titration techniques (GITTs). Due to the unique structure, the obtained material displays an excellent electrochemical performance, which lays the foundation for the improvement in the performance of waste biomass in LIBs/SIBs.

In recent years, with the vigorous development and gradual deployment of new energy vehicles, more attention has been paid to the research on lithium-ion batteries (LIBs). Compared with the booming LIBs, lithium primary batteries (LPBs) own superiority in specific energy and self-discharge rate and are usually applied in special fields such as medical implantation, aerospace, and military. Widespread application in special fields also means more stringent requirements for LPBs in terms of energy density, working temperature range and shelf life. Therefore, how to obtain LPBs with high energy density, wide operational temperature range and long storage life is of great importance in future development. In view of the above, this paper reviews the latest research on LPBs in cathode, anode and electrolyte over the years, and puts forward relevant insights for LPBs, along with the intention to explore avenues for the design of LPBs components in the coming decades and promote further development in this field.

Dual-ion battery (DIB) composed of graphite cathode and lithium anode is regarded as an advanced secondary battery because of the low cost, high working voltage and environmental friendliness. However, DIB operated at high potential (usually ≥ 4.5 V versus Li+/Li) is confronted with severe challenges including electrolyte decomposition on cathode interface, and structural deterioration of graphite accompanying with anions de-/intercalation, hinder its cyclic life. To address those drawbacks and preserve the DIB virtues, a feasible and scalable surface modification is achieved for the commercial graphite cathode of mesocarbon microbead. In/ex-situ studies reveal that, such an interfacial engineering facilitates and reconstructs the formation of chemically stable cathode electrolyte interphase with better flexibility alleviating the decomposition of electrolyte, regulating the anions de-/intercalation behavior in graphite with the retainment of structural integrity and without exerting considerable influence on kinetics of anions diffusion. As a result, the modified mesocarbon microbead exhibits a much-extended cycle life with high capacity retention of 82.3% even after 1000 cycles. This study demonstrates that the interface modification of electrode and coating skeleton play important roles on DIB performance improvement, providing the feasible basis for practical application of DIB owing to the green and scalable coating procedures

As the power supply of the prosperous new energy products, advanced lithium ion batteries (LIBs) are widely applied to portable energy equipment and large-scale energy storage systems. To broaden the applicable range, considerable endeavours have been devoted towards improving the energy and power density of LIBs. However, the side reaction caused by the close contact between the electrode (particularly the cathode) and the electrolyte leads to capacity decay and structural degradation, which is a tricky problem to be solved. In order to overcome this obstacle, the researchers focused their attention on electrolyte additives. By adding additives to the electrolyte, the construction of a stable cathode-electrolyte interphase (CEI) between the cathode and the electrolyte has been proven to competently elevate the overall electrochemical performance of LIBs. However, how to choose electrolyte additives that match different cathode systems ideally to achieve stable CEI layer construction and high-performance LIBs is still in the stage of repeated experiments and exploration. This article specifically introduces the working mechanism of diverse electrolyte additives for forming a stable CEI layer and summarizes the latest research progress in the application of electrolyte additives for LIBs with diverse cathode materials. Finally, we tentatively set forth recommendations on the screening and customization of ideal additives required for the construction of robust CEI layer in LIBs. We believe this minireview will have a certain reference value for the design and construction of stable CEI layer to realize desirable performance of LIBs.

Phosphate cathode materials are practical for use in sodium-ion batteries (SIBs) owing to their high stability and long-term cycle life. In this work, the temperature-dependent properties of the phosphate cathode Na3 V2 (PO4 )2 O2 F (NVPOF) are studied in a wide temperature range from -25 to 55 °C. Upon cycling at general temperature (above 0 °C), the NVPOF cathode retains an excellent charge/discharge performance, and the rate capability is noteworthy, indicating that NVPOF is a competitive candidate as a temperature-adaptive cathode for SIBs. Upon decreasing the temperature below 0 °C, the cell performance deteriorates, which may be caused by the electrolyte and Na electrode, based on the study of ionic conductivity and electrode kinetics. This work proposes a new breakthrough point for the development of SIBs with high performance over a wide temperature range for advanced power systems.

One main challenge for phosphate cathodes in sodium-ion batteries (SIBs) is to increase the working voltage and energy density to promote its practicability. Herein, an advanced Na3V2(PO4)2F3@C cathode is prepared successfully for sodium-ion full cells. It is revealed that, carbon coating can not only enhance the electronic conductivity and electrode kinetics of Na3V2(PO4)2F3@C and inhibit the growth of particles (i.e., shorten the Na+-migration path), but also unexpectedly for the first time adjust the dis-/charging plateaux at different voltage ranges to increase the mean voltage (from 3.59 to 3.71 V) and energy density (from 336.0 to 428.5 Wh kg−1) of phosphate cathode material. As a result, when used as cathode for SIBs, the prepared Na3V2(PO4)2F3@C delivers much improved electrochemical properties in terms of larger specifc capacity (115.9 vs. 93.5 mAh g−1), more outstanding high-rate capability (e.g., 87.3 vs. 60.5 mAh g−1 at 10 C), higher energy density, and better cycling performance, compared to pristine Na3V2(PO4)2F3. Reasons for the enhanced electrochemical properties include ionicity enhancement of lattice induced by carbon coating, improved electrode kinetics and electronic conductivity, and high stability of lattice, which is elucidated clearly through the contrastive characterization and electrochemical studies. Moreover, excellent energy-storage performance in sodium-ion full cells further demonstrate the extremely high possibility of Na3V2(PO4)2F3@C cathode for practical applications.

Polyanion-type compounds, used as promising cathode materials for sodium-ion batteries (SIBs), have attracted great attention because of their suitable operating voltage, stable framework and good thermal stability. However, they suffer from inherent low conductivity, poor high-rate capability and unsatisfactory cycle stability. Herein, in order to overcome these deficiencies, a feasible strategy, which integrates high conductivity reduced graphene oxide (rGO) with the representative vanadium-based fluorophosphates to form a 3D carbon network constructed in NaVPO4F, is proposed and investigated. Based on microstructural and morphological characterization, the NaVPO4F nanoparticles are successfully synthesized and uniformly embedded in a robust rGO carbon network. Ascribed to the multifunctional structure design, the reaction kinetics of NaVPO4F were significantly improved, as demonstrated by the electrochemical impedance spectroscopy, cyclic voltammetry at varied scan rates and galvanostatic intermittent titration technique. Moreover, the hard carbon (HC) and the NaVPO4F@rGO composite are employed as the anode and the cathode, respectively, to fabricate a sodium-ion full battery, which exhibits an excellent high-rate capability (75.1 mA h g−1 at 15C) and an outstanding cycling stability (0.0115% capacity decay per cycle over 1500 cycles at 5C rate). This study provides a feasible and effective method to develop high-performance polyanion-type electrode materials for SIBs.

Impossible voltage plateau regulation for the cathode materials with fixed active elemental center is a pressing issue hindering the development of Na-superionic-conductor (NASICON)-type Na

Lithium oxides are the most promising cathode candidates for high-performance lithium-ion batteries (LIBs), owing to their high theoretical capacity and average working voltage, which are conducive to achieving the ultimate goal of upgrading energy density. By raising the upper limit of the cutoff voltage, we may be able to further improve both the practical capacity and average voltage of lithium oxide cathodes. Unfortunately, the high-voltage operation of these cathodes results in significant challenges, namely, reduced surface structural stability and interfacial stability with electrolytes, thus degrading the electrochemical performance. Accordingly, surface/interface modification strategies, including surface coating, electrolyte regulation, binder design, and special surface treatments, are systematically summarized and comprehensively analyzed for high-voltage lithium oxide cathode materials in this review. Furthermore, the corresponding modification mechanisms are discussed in detail to better grasp the internal mechanisms for the enhanced electrochemical performance. Based on recent progress, we further propose predictable development directions for high-performance LIBs in future practical applications. This review provides new insights into various high-voltage lithium oxide cathodes and their universal surface/interface modification strategies towards advanced next-generation LIBs with high energy and power density and long cycle life.

With the rapid development of sodium-ion batteries (SIBs), it is urgent to exploit the cathode materials with good rate capability, attractive high energy density and considerable long cycle performance. Na3V2(PO4)3 (NVP), as a NASICON-type electrode material, is one of the cathode materials with great potential for application because of its good thermal stability and stable. However, NVP has the inherent problem of low electronic conductivity, and various strategies are proposed to improve it, moreover, nanotechnology or nanostructure are involved in these strategies, the construction of nanostructured active particles and nanocomposites with conductive carbon networks have been shown to be effective in improving the electrical conductivity of NVP. Herein, we review the research progress of NVP performance improvement strategies from the perspective of nanostructures and classifies the prepared nanomaterials according to their different nano-dimension. In addition, NVP nanocomposites are reviewed in terms of both preparation methods and promotion effects, and examples of NVP nanocomposites at different nano-dimension are given. Finally, some personal views are presented to provide reasonable guidance for the research and design of high-performance polyanionic cathode materials of SIBs.

Constructing potential anodes for sodium-ion batteries (SIBs) with a wide temperature property has captured enormous interests in recent years. Fe1−xS, a zero-band gap material confirmed by density states calculation, is an ideal electrode for fast energy storage on account of its low cost and high theoretical capacity. Herein, Fe1−xS nanosheet wrapped by nitrogen-doped carbon (Fe1−xS@NC) is engineered through a post-sulfidation strategy using Fe-based metal-organic framework (Fe-MOF) as the precursor. The obtained Fe1−xS@NC agaric-like structure can well shorten the charge diffusion pathway, and significantly enhance the ionic/electronic conductivities and the reaction kinetics. As expected, the Fe1−xS@NC electrode, as a prospective SIB anode, delivers a desirable capacity up to 510.2 mA h g−1 at a high rate of 8000 mA g−1. Additionally, even operated at low temperatures of 0 and −25°C, high reversible capacities of 387.1 and 223.4 mA h g−1 can still be obtained at 2000 mA g−1, respectively, indicating its huge potential use at harsh temperatures. More noticeably, the full battery made by the Fe1−xS@NC anode and Na3V2(PO4)2O2F cathode achieves a remarkable rate capacity (186.8 mA h g−1 at 2000 mA g−1) and an impressive cycle performance (183.6 mA h g−1 after 100 cycles at 700 mA g−1) between 0.3 and 3.8 V. Such excellent electrochemical performance is mainly contributed by its pseudocapacitive dominated behavior, which brings fast electrode kinetics and robust structural stability to the whole electrode.

The intrinsic charge-transfer property bears the primary responsibility for the sluggish redox kinetics of the common electrode materials, especially operated at low temperatures. Herein, we report...

Na super ionic conductor (NASICON)-structured materials have evolved to play many critical roles in battery systems because of their three-dimensional framework structures. Here, by coupling NASICON-structured Na3V2(PO4)2O2F cathodes and Na3V2(PO4)3 anodes, an asymmetric Na-ion-based full cell exhibits two flat voltage plateaus at about 2.3 and 1.9 V and a high capacity of 101 mA h/g. Moreover, an all-solid-state Na-ion battery has been further enabled by the concept of using all NASICON-structured materials, including cathodes, anodes, and electrolytes (Na5YSi4O12), which delivers a high output voltage. Importantly, the full cell displays high safety without using a flammable organic liquid electrolyte and superior structure stability with all NASICON-structured materials.

Sodium-ion batteries (SIBs) have been considered as one of foremost promising alternatives for the widely used lithium-ion batteries. In order to assemble high-performance SIBs, cathode materials with stable structure and superior electrochemical properties are needed emphatically. In this work, we prepare a new layered oxide material, P2-type Na2/3Mn1/2Co1/3Cu1/6O2 (P2-MCC) with the morphology of hexagonal micro-prisms, by a sol-gel method. When used as cathode material for SIBs, the P2-MCC exhibits good cycling stability (e.g., >83.5% capacity retention after 100 cycles at 100 mA g−1) and superior high-rate performance. Moreover, it also owns an attractive ability of fast-charging, e.g., a high capacity retention of ∼66% after 100 cycles as charging at a high current density of 200 mA g−1 and discharging at a low current density of 10 mA g−1. Such good electrochemical properties can be originated from the synergetic improvement of selected multi-metallic ions and enhanced electrode kinetics (high apparent Na-diffusion kinetics) which is demonstrated by the galvanostatic intermittent titration technique, electrochemical impedance spectroscopy and cyclic voltammetry at various scan rates.

Owing to the high working voltage and energy-storage density and excellent cycling stability, Na3V2(PO4)2O2F (NVPOF) has been recognized as a promising cathode material for sodium ion batteries (SIBs). Usually, NVPOF is prepared by a high-temperature solid-state method, which easily leads to many deficiencies including large particle size, irregular morphology and poor high-rate capability. In order to avoid these deficiencies, the present study reveals a simple hydrothermal method to effectively regulate the morphology and size uniformity of the NVPOF particles and optimize the electrochemical properties by precisely adjusting the key preparation parameters including pH and temperature. It is disclosed that the optimized NVPOF prepared at pH = 7.00 ± 0.05 and 170 °C can achieve outstanding electrochemical properties in terms of high specific capacity of 123.2 mA h g−1 at 0.1 C, superior high-rate capability of 85.9 mA h g−1 at 20 C and long cycling stability (e.g., a capacity retention up to 94.8% at 1 C after 500 cycles). All of the properties are obviously better than those of the controls obtained at other preparation parameters. The much enhanced performance should be beneficial from the short and fast Na+ transport pathways because of the high uniformity and nanometer size of the NVPOF particles, making them a promising cathode material for high-performance SIBs.

A carbon-incorporated LiMnBO3/boron oxide composite (LMB/BxOy@C) is prepared as an advanced anode material for lithium-ion batteries (LIBs). The prepared LMB/BxOy@C can deliver a reversible capacity of about 362.5 mAh g−1 at a low current density of 0.04 A g−1. When cycled at 2.0 A g−1, the specific capacity increases from 159.7 mAh g−1 at the 100th cycle to 263.3 mAh g−1, which still maintains at 259 mAh g−1 after 1000 cycles. The excellent cycling performance and boosting effect of capacity should be due to the existence of conductive carbon network, the inactive boron oxide to provide outstanding structural stability, and the activation of the transformation between Mn2+ and Mn4+ during cycling. The preliminary result illustrates that the prepared LMB/BxOy@C could be a promising anode material for LIBs.

Sodium-ion batteries (SIBs) are heralded as promising candidates for grid-scale energy storage systems due to their low cost and abundant sodium resources. Excellent rate capacity and outstanding cycling stability are always the goals for SIBs. Up to now, nearly all attention has been focused on the control of morphology and structure of electrode materials, but the influence of binders on their performance is neglected, especially in cathode materials. Herein, using Na3V2(PO4)2O2F (NVPOF) as a cathode material, the influence of four different binders (sodium alginate, SA; carboxymethylcellulose sodium, CMC; poly(vinylidene fluoride), PVDF; and poly(acrylic latex), LA133) on its electrochemical performance is studied. As a result, when using SA as the binder, the electrochemical performance of the NVPOF electrode is improved significantly, which is mainly because of the high water solubility, rich carboxyl and hydroxyl groups, and high adhesive and cohesive properties of the SA binder, leading to the uniform distribution of active materials NVPOF and carbon black in electrodes, good integrity, low polarization, and superior kinetic properties of the NVPOF electrodes, as demonstrated by scanning electron microscopy, cyclic voltammetry, electrochemical impedance spectroscopy, and galvanostatic intermittent titration technique. More importantly, when coupled with a hard carbon anode, the fabricated sodium-ion full cells also exhibit excellent rate performance, thus providing a preview of their practical application. This work shows that the battery performance can be improved by matching suitable binder systems, which is believed to have great importance for the further optimization of the electrochemical performance of SIBs.

Phosphate cathode materials are practical for use in sodium-ion batteries (SIBs) owing to their high stability and long-term cycle life. In this work, the temperature-dependent properties of the phosphate cathode Na

Due to the Earth’s scarcity of lithium, replacing lithium with earth-abundant and low-cost sodium for sodium-ion batteries (SIBs) has recently become a promising substitute for lithium-ion batterie...

As a promising cathode material of sodium-ion battery, P2-type Na2/3Ni1/3Mn2/3O2 (NNMO) possesses a theoretically high capacity and working voltage to realize high energy storage density. However, it still suffers from poor cycling stability mainly incurred by the undesirable P2–O2 phase transition. Herein, the electrochemically active Fe3+ ions are introduced into the lattice of NNMO, forming Na2/3Ni1/3Mn2/3–xFexO2 (x = 0, 1/24, 1/12, 1/8, 1/6) to effectively stabilize the P2-type crystalline structure. In such Fe-substituted materials, both Ni2+/Ni4+ and Fe3+/Fe4+ couples take part in the redox reactions, and the P2–O2 phase transition is well restrained during cycling, as verified by ex situ X-ray diffraction. As a result, the optimized Na2/3Ni1/3Mn7/12Fe1/12O2 (1/12-NNMF) has a long-term cycling stability with the fading rate of 0.05% per cycle over 300 cycles at 5 C. Furthermore, the 1/12-NNMF delivers excellent rate capabilities (65 mA h g–1 at 25 C) and superior low-temperature performance (the cap...

Developing a high-performance, low-cost, and safer rechargeable battery is a primary challenge in next-generation electrochemical energy storage. In this work, a quasi-solid-state (QSS) sodium-ion full battery (SIFB) is designed and fabricated. Hard carbon cloth derived from cotton cloth and Na3V2(PO4)2O2F (NVPOF) are employed as the anode and the cathode, respectively, and a sodium ion-conducting gel-polymer membrane is used as both the QSS electrolyte and separator, accomplishing the high energy and power densities in the QSS sodium-ion batteries. The energy density can reach 460 W h kg–1 according to the mass of the cathode materials. Moreover, the fabricated QSS SIFB also exhibits an excellent rate performance (e.g., about 78.1 mA h g–1 specific capacity at 10 C) and a superior cycle performance (e.g., ∼90% capacity retention after 500 cycles at 10 C). These results show that the developed QSS SIFB is a hopeful candidate for large-scale energy storage.

As a promising anode candidate for lithium ion batteries (LIBs), MnO has attracted wide attentions owing to its theoretically high Li-storage capacity, lower working voltage and polarization than other oxides, low cost, environmental friendliness, and abundant resources. Herein, we develop a facile and low-cost strategy to fabricate a unique porous MnO@N-doped carbon (MnO@N-C) nanotube and demonstrate its outstanding Li-storage properties as anode material for LIBs. Benefiting from its unique 1D porous features, the prepared MnO@N-C electrodes exhibit high reversible specific capacity (971.8 mAh g−1 at 0.1 A g−1), superb high-rate capability (359.5 mAh g−1 at 30 A g−1) and remarkable cycling stability (441.5 mA h g−1 after 3500 cycles at 10 A g−1). Such superior electrochemical performance should be due to the high conductivity and protection effects of N-doped carbon layer, and adequate internal voids in the MnO@N-C to effectively accommodate the volume changes of MnO during cycling. In addition, it is also disclosed that the high capacity contribution arises from the pseudocapacitive charge storage.

A novel core–shell Fe3O4@FeS composed of Fe3O4 core and FeS shell with the morphology of regular octahedra has been prepared via a facile and scalable strategy via employing commercial Fe3O4 as the precursor. When used as anode material for sodium-ion batteries (SIBs), the prepared Fe3O4@FeS combines the merits of FeS and Fe3O4 with high Na-storage capacity and superior cycling stability, respectively. The optimized Fe3O4@FeS electrode shows ultralong cycle life and outstanding rate capability. For instance, it remains a capacity retention of 90.8% with a reversible capacity of 169 mAh g–1 after 750 cycles at 0.2 A g–1 and 151 mAh g–1 at a high current density of 2 A g–1, which is about 7.5 times in comparison to the Na-storage capacity of commercial Fe3O4. More importantly, the prepared Fe3O4@FeS also exhibits excellent full-cell performance. The assembled Fe3O4@FeS//Na3V2(PO4)2O2F sodium-ion full battery gives a reversible capacity of 157 mAh g–1 after 50 cycles at 0.5 A g–1 with a capacity retention of...

In this article, an effective strategy (viz., constructing multiple heterointerfaces) is proposed to develop superior electrode materials for sodium-ion battery (SIB), which is the most promising alternative to market-dominant lithium-ion battery for stationary energy storage. In the as-prepared heterogeneous-SnO2/Se/graphene (h-SSG) composite, there exists multiple phase interfaces, including heterointerfaces between tetragonal and orthorhombic SnO2 (t-/o-SnO2) in the heterogeneous SnO2 nanojunctions and two phase interfaces between t/o-SnO2 and amorphous Se. These multiple phase interfaces promise the much improved Na storage properties of h-SSG when compared to four controls without such multiple heterointerfaces because the multiple built-in electric fields at the heterointerfaces can significantly boost the surface reaction kinetics and facilitate charge transport as demonstrated by kinetics analyses, theoretical calculations and contrastive electrochemical tests. Moreover, h-SSG also exhibits superior Na-ion full cell performance when coupled with a high-voltage Na3V2(PO4)2O2F cathode. In view of the universality of the heterointerface-based enhancement effect on surface reaction and charge transport kinetics and the facile preparation procedures, the present strategy should be universal to develop other superior electrode materials for high-performance SIBs and other batteries for future energy storage applications.

Resolving the large volume changes and achieving the ultrafast charge-discharge capability for the alloy anode of sodium-ion batteries (SIBs) are needed urgently. Rational design of unique structure is an effective strategy to solve these problems. Herein, we reported a facile route to synthesize a layer-stacked Sb@graphene (LS-Sb@G) micro/nanocomposite via solvothermal method by using a mild reducing agent. In the LS-Sb@G, the Sb nanosheets are uniformly pasted on the graphene matrix and embedded into the interlayers, which leading to the formation of tight layer-by-layer micro/nanostructure. When employed as anode materials for SIBs, the unique structural characteristics offer the LS-Sb@G micro/nanocomposite with impressive Na-storage properties, such as high Na-storage capacity of 495.2 mAh/g after 100 cycles at 125 mA/g and decent rate capabilities up to 6 A/g. In addition, the LS-Sb@G electrode achieves superior electrochemical performance with a high reversible capacity of 116.5 mAh/g at 0.1 C (1 C = 120 mA/g) for sodium-ion full cells. Moreover, we firstly studied the low-temperature Na-storage performance of Sb-based composite at −20 °C. The LS-Sb@G composite demonstrated good low-temperature properties (e.g., 506.6 and 472.5 mAh/g at 25 and 50 mA/g at −20 °C, respectively) for SIBs, which endow great promise as an anode material for the normal operation of electric vehicles under low temperature condition.