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Sodium‐ion batteries (SIBs), based on hard carbon anodes and Na+‐intercalation compound cathodes, have gained significant attention. Nonetheless, hard carbon anodes involve the storage of Na+ at a low potential, typically below 0.1 V (vs Na/Na+), which increases the risk of dendritic Na growth on the anode surface during overcharging. Herein, a safe organic/inorganic composite anode containing tetrasodium 3,4,9,10‐perylenetetracarboxylate (Na4PTC) and Metallic bismuth (Bi) with a weight ratio of 7:2, which exhibits an average potential of 0.7 V (vs Na+/Na) and a capacity of 150 mAh g−1 is proposed. The electrode reaction involves a reversible coordination reaction within the organic host and alloying reactions within the metallic Bi component. Importantly, the organic component efficiently buffers the volume changes in Bi during the alloying reaction, while the metallic Bi enhances the electronic conductivity of the organic material. As a result, this composite anode shows high cycle stability and rate performance, even under high mass loadings ranging from 10 to 50 mg cm−2. Furthermore, it is demonstrated that the Na‐ion full cell, consisting of the composite anode and the Na3V2O2(PO4)2F cathode, exhibits minimal capacity degradation over 100 cycles while maintaining a high areal capacity of 1.1 mA cm−2. [ABSTRACT FROM AUTHOR]

Sodium‐ion batteries (SIBs), as one of the potential candidates for grid‐scale energy storage systems, are required to tackle extreme weather conditions. However, the all‐weather SIBs with a wide operation‐temperature range are rarely reported. Herein, we propose a wide‐temperature range SIB, which involves a carbon‐coated Na4Fe3(PO4)2P2O7 (NFPP@C) cathode, a bismuth (Bi) anode, and a diglyme‐based electrolyte. We demonstrate that solvated Na+ can be directly stored by the Bi anode via an alloying reaction without the de‐solvent process. Furthermore, the NFPP@C cathode exhibits a high Na+ diffusion coefficient at low temperature. As a result, the Bi//NFPP@C battery exhibits perfect low‐temperature behavior. Even at −70 °C, this battery still delivers 70.19 % of the room‐temperature capacity. Furthermore, benefitting from the high boiling point of the electrolyte, this battery also works well at a high temperature of up to 100 °C. These results are encouraging for the further exploration of wide‐temperature range SIBs. [ABSTRACT FROM AUTHOR]

A nitrogen-doped, carbon-coated Na3V2(PO4)3 cathode material is synthesized and the formation of doping type of nitrogen-doped in carbon coating layer is systemically investigated. Three different carbon-nitrogen species: pyridinic N, pyrrolic N, and quaternary N are identified. The most important finding is that different carbon-nitrogen species in the carbon layer have different impacts on the improvement of the electrochemical properties of Na3V2(PO4)3. Pyridinic N and pyrrolic N significantly increase the electronic conductivity and create numerous extrinsic defects and active sites. Quaternary N only increases the electronic conductivity without creating extrinsic defects. Therefore, it is unexpectedly demonstrated that the Na3V2(PO4)3/C+N, in which with minimize content of quaternary N or exist most extrinsic defects, exhibits the best electrochemical performance, particularly the rate performance and cycling stability. For example, when the discharging rate increased from 0.2 C to 5 C, its capacity of 101.9 mAh g−1 decays to 84.3 mAh g−1 and an amazing capacity retention of 83% is achieved. Moreover, even at higher current density of 5 C, an excellent capacity retention of 93% is maintained even after 100 cycles. [ABSTRACT FROM AUTHOR]

With the increasing demand for low cost, long lifetime, high energy density storage systems, an extensive amount of effort has recently been focused on the development of sodium‐ion batteries (SIBs), and a variety of cathode materials have been discovered. However, looking for the most suitable anode material for practical application is a major challenge for SIBs. Herein, a high capacity sulfur‐doped black phosphorus‐TiO2 (TiO2‐BP‐S) anode material for SIBs is first synthesized by a feasible and large‐scale high‐energy ball‐milling approach, and its stability in air exposure is investigated through X‐ray photoelectron spectroscopy. The morphology of TiO2‐BP‐S is characterized using transmission electron microscopy, indicating that the TiO2 nanoparticles produce PTi bonds with BP. The TiO2‐BP‐S composite with PS and PTi bonds exhibits excellent stability in air and the superior electrochemical performance. For example, the discharge specific capacity is up to 490 mA h g−1 after 100 cycles at 50 mA g−1, and it remains at 290 mA h g−1 after 600 cycles at 500 mA g−1. Meanwhile, the scientific insight that the formation of stable PS and PTi bonds can provide a guide for the practical large‐scale application of SIBs in other titanium base and black phosphorus materials is looked forward. [ABSTRACT FROM AUTHOR]

Abstract As a safe, low-voltage anode material, in recent years, Na 2 Ti 3 O 7 has become regarded as a highly alternative negative material for high energy room-temperature sodium ion batteries. However, its poor ion and electron conductivity produces very poor electrochemical performance of Na 2 Ti 3 O 7 , therefore greatly limiting its practical application in future scalable utilization. We report here a self-doping of Ti3+ into the Na 2 Ti 3 O 7 electrode material, through a very simple post heat-treatment process, that is, annealing the Na 2 Ti 3 O 7 precursor at an argon atmosphere containing 5% H 2. By XPS characterization, it is confirmed that Ti3+ is successfully doped into Na 2 Ti 3 O 7. Benefiting from this self-doped Ti3+ with larger ionic radius and better electronic conductivity, the obtained Na 2 Ti 3 O 7 demonstrates improved electron conductivity and ion diffusion properties. Combined with a carbon coating, this self-doped Na 2 Ti 3 O 7 electrode material exhibits superior electrochemical performance to that of non-doped electrode, e.g., this Na 2 Ti 3 O 7 sample could delivers a specific capacity of 187.8 and 51.9 mAh g−1 from 0.1C to 10C at various rate of discharge, respectively. When recycled back to 0.1C, it can still reach 153 mAh g−1. Compared with numerous reported nanoscale means, we believe this approach is practical and productive, and may extend to other ti-based electrode materials. Highlights • A self-doped Ti3+ of Na 2 Ti 3 O 7 anode is synthesized by a facile sol-gel process. • The Ti3+ enhances the electronic conductivity of Na 2 Ti 3 O 7. • The Ti3+ in crystal lattice of Na 2 Ti 3 O 7 enhances the Na+ diffusion coefficient. • This self-doped Na 2 Ti 3 O 7 material exhibits improved electrochemical performance. [ABSTRACT FROM AUTHOR]

Metal sulfides are considered potential anode materials for sodium ion batteries (SIBs) due to their unique structure and high theoretical capacities. Nevertheless, the low intrinsic electrical conductivity and sluggish electrochemical reaction kinetics lead to inferior electrochemical performance, which greatly limits their practical application. In this work, we successfully constructed N, S co-doped carbon modified NiS/MoS 2 heterostructures (denoted as NiS/MoS 2) via a simple one-step hydrothermal method. The as-prepared sample was corroborated as an advanced anode for SIBs that simultaneously achieved high reversible capacity (670.2 mA h g−1 at 0.5 A g−1), excellent rate capability (249 mA h g−1 at 40 A g−1), and long-term cycling stability (573.8 mA h g−1 after 1000 cycles at 2 A g−1). Furthermore, the superior cycle and rate performance are also reflected in the sodium-ion full cell, which demonstrates the potential value of the NiS/MoS 2 anode in practical applications. The bimetallic sulfide heterostructure distinctly lowers the Na + diffusion energy barrier and elevates the reaction kinetics by a built-in electric field effect. In addition, the doping of N, S elements can form a strong bond with carbon to accommodate the volume change and boost the electron transfer. This work provides a valuable reference to develop advanced anode materials for SIBs for practical applications. [Display omitted] ● N, S co-doped carbon modified NiS/MoS 2 with heterostructure is synthesized. ● The heterostructure reduces the Na + diffusion energy barrier across NiS/MoS 2. ● The heterointerface induces a built-in electric field to enhance charge transfer. ● N, S co-doped carbon improves the electrical conductivity of the material. ● The above strategy makes NiS/MoS 2 showing excellent performance. [ABSTRACT FROM AUTHOR]

[Display omitted] • AlF 3 coated nanoscaled Na 3.12 Fe 2.44 (P 2 O 7) 2 @CNTs is synthesized. • Carbon nanotubes build highly conductive networks. • The AlF 3 layer facilitates the formation of cathode-electrolyte interphase film. • AlF 3 coating improves materials structural stability at high temperatures. Sodium ion batteries (SIBs) are applied to the field of energy storage due to their unique advantages, however, large scale energy storage equipment, also requires low cost, good cycling performance, safety performance and good environmental adaptation performance, in order to cope with various climatic conditions. The polyanionic material Na 3.12 Fe 2.44 (P 2 O 7) 2 (NFPO) is considered to be an excellent cathode material for SIBs due to its unique large frame work structure and good thermal stability, leading to good cycle stability and a wide working temperature. Nevertheless, poor intrinsic conductivity of the material brings about large polarization, resulting in low electrochemical reversibility. Especially in high temperature environment, the electrolyte aggravates the erosion of the material and increases the side reactions, making the cycle stability worse. In this study, nanoscale NFPO composites are synthesized by an optimized sol–gel method, while the interface is modified using AlF 3 , to achieve resistance to surface oxidation and corrosion. Impressively, these modified materials exhibit high-temperature electrochemical properties due to the thermal stability and interfacial protection of AlF 3. At 60 °C, it provides a discharge capacity of 130 mAh g−1 at 0.1C, still has a discharge capacity of 100.4 mAh g−1 at 10C, a capacity retention rate of 96.3% after 400 cycles, and has excellent long-term cycling performance (70% capacity retention rate after 6000 cycles at 50C). This work demonstrates the effectiveness of the interfacial modification and provides an impactful strategy for the design of batteries at high temperatures. [ABSTRACT FROM AUTHOR]