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LiPF6 as a dominant lithium salt of electrolyte is widely used in commercial rechargeable lithium‐ion batteries due to its well‐balanced properties, including high solubility in organic solvents, good electrochemical stability, and high ionic conductivity. However, it suffers from several undesirable properties, such as high moisture sensitivity, thermal instability, and high cost. To address these issues, herein, we propose an electron‐donation modulation (EDM) rule for the development of low‐cost, sustainable, and electrochemically compatible LiNO3‐based electrolytes. We employ high donor‐number solvents (HDNSs) with strong electron‐donation ability to dissolve LiNO3, while low donor‐number solvents (LDNSs) with weak electron‐donation ability are used to regulate the solvation structure to stabilize the electrolytes. As an example, we design the LiNO3‐DMSO@PC electrolyte, where DMSO acts as an HDNS and PC serves as an LDNS. This electrolyte exhibits excellent electrochemical compatibility with graphite anodes, as well as the LiFePO4 and LiCoO2 cathodes, leading to stable cycling over 200 cycles. Through spectroscopy analyses and theoretical calculation, we uncover the underlying mechanism responsible for the stabilization of these electrolytes. Our findings provide valuable insights into the preparation of LiNO3‐based electrolytes using the EDM rule, opening new avenues for the development of advanced electrolytes with versatile functions for sustainable rechargeable batteries. [ABSTRACT FROM AUTHOR]

Metal sulfides with excellent redox reversibility and high capacity are very promising electrode materials for sodium‐ion batteries. However, their practical application is still hindered by the poor rate capability and limited cycle life. Herein, a template‐based strategy is developed to synthesize nitrogen‐doped carbon‐coated Cu9S5 bullet‐like hollow particles starting from bullet‐like ZnO particles. With the structural and compositional advantages, these unique nitrogen‐doped carbon‐coated Cu9S5 bullet‐like hollow particles manifest excellent sodium storage properties with superior rate capability and ultra‐stable cycling performance. [ABSTRACT FROM AUTHOR]

Metal sulfides have received considerable attention for efficient sodium storage owing to their high capacity and decent redox reversibility. However, the poor rate capability and fast capacity decay greatly hinder their practical application in sodium‐ion batteries. Herein, an elegant multi‐step templating strategy has been developed to rationally synthesize hierarchical double‐shelled nanoboxes with the CoS2 nanosheet‐constructed outer shell supported on the CuS inner shell. Their structure and composition enable these hierarchical CuS@CoS2 nanoboxes to show boosted electrochemical properties with high capacity, outstanding rate capability, and long cycle life. [ABSTRACT FROM AUTHOR]

Abstract: Antimony‐based electrode materials with high specific capacity have aroused considerable interest as anode materials for sodium‐ion batteries (SIBs). Herein, we develop a template‐engaged ion‐exchange method to synthesize Sb2Se3 microclips, and the as‐obtained Sb2Se3 microclips are further in situ coated with polypyrrole (PPy). Benefiting from the structural and compositional merits, these PPy‐coated Sb2Se3 microclips exhibit enhanced sodium‐storage properties in terms of high reversible capacity, superior rate capability, and stable cycling performance. [ABSTRACT FROM AUTHOR]

Abstract: Hard carbon is regarded as the most promising anode material for commercialization of Na ion batteries because of its high capacity and low cost. At present, the practical utilization of hard carbon anodes is largely limited by the low initial Coulombic efficiency (ICE). Na ions have been found to adopt an adsorption–insertion storage mechanism. In this paper a systematic way to control the defect concentration and porosity of hard carbon with similar overall architectures is shown. This study elucidates that the defects in the graphite layers are directly related to the ICE as they would trap Na ions and create a repulsive electric field for other Na ions so as to shorten the low‐voltage intercalation capacity. The obtained low defect and porosity hard carbon electrode has achieved the highest ICE of 86.1% (94.5% for pure hard carbon material by subtracting that of the conductive carbon black), reversible capacity of 361 mA h g−1, and excellent cycle stability (93.4% of capacity retention over 100 cycles). This result sheds light on feasible design principles for high performance Na storage hard carbon: suitable carbon layer distance and defect free graphitic layers. [ABSTRACT FROM AUTHOR]

Layered metal oxides have attracted increasing attention as cathode materials for sodium-ion batteries (SIBs). However, the application of such cathode materials is still hindered by their poor rate capability and cycling stability. Here, a facile self-templated strategy is developed to synthesize uniform P2-Na0.7CoO2 microspheres. Due to the unique microsphere structure, the contact area of the active material with electrolyte is minimized. As expected, the P2-Na0.7CoO2 microspheres exhibit enhanced electrochemical performance for sodium storage in terms of high reversible capacity (125 mAh g−1 at 5 mA g−1), superior rate capability and long cycle life (86 % capacity retention over 300 cycles). Importantly, the synthesis method can be easily extended to synthesize other layered metal oxide (P2-Na0.7MnO2 and O3-NaFeO2) microspheres. [ABSTRACT FROM AUTHOR]

A TiO2@reduced graphene oxide (TiO2@rGO) composite is synthesized successfully by a simple spray-drying method. The structural and morphological characterizations reveal that the TiO2@rGO composite has a sphere-like morphology with diameters of 5-15 µm, and each microsphere is actually a random aggregation of primary TiO2 nanoparticles, which are tightly covered by soft graphene sheets. The TiO2@rGO electrode exhibits enhanced electrochemical performance of high charge capacity (170 mA h g−1 at 0.1 C), long cycling life (87% of capacity retention after 300 cycles at 0.2 C), and high rate capability (55 mA h g−1 at 10 C). Compared with bare TiO2 microspheres, the improved electrochemical performance of the TiO2@rGO composite benefits from the introduction of graphene as a highly conductive, flexible, and large-surface-area scaffold to provide good electronic contact between active materials, suppress the aggregation of intermediate products, and alleviate the volume change during sodiation and desodiation. The encouraging experimental results suggest that the TiO2@rGO composite has great potential as a high-capacity and high-stability anode for the sodium-ion batteries. [ABSTRACT FROM AUTHOR]

In article number 1803052, Changzhou Yuan, Xiong Wen (David) Lou and co‐workers design and fabricate a ternary Fe1−xS@porous carbon nanowires/reduced graphene oxide (Fe1−xS@PCNWs/rGO) hybrid film anode via scale‐up assembly and sulfuration methodologies. It exhibits superior volumetric and gravimetric capacity toward next‐generation sodium ion batteries. More competitively, a flexible Fe1−xS@PCNWs/rGO‐based full device demonstrates outstanding electrochemical Na‐storage properties, highlighting its enormous potential in versatile flexible and wearable applications. [ABSTRACT FROM AUTHOR]

The structure and phase evolution characteristics of the Na 6-2 x Fe x (SO 4) 3 (1.5≤x≤2.0) system are comprehensively investigated by both experimental and computational methods. It reveals that a pure phase exists in the 1.6≤ x ≤1.7 region, and part of Na ions tend to occupy Fe sites to form more stable frameworks. The NFSO-1.7 exhibits the best electrochemical performance among the NFSO- x samples, delivering a high discharge capacity (104.5 mAh g−1 at 0.1C), excellent rate performance (81.5 mAh g−1 at 30C), and remarkable cycle stability over 10,000 cycles with a high-capacity retention rate of 72.4%. [Display omitted] Fe-based polyanionic sulfate materials are one of the most promising candidates for large-scale applications in sodium-ion batteries due to their low cost and excellent electrochemical performance. Although great achievements have been gained on a series of Na 6−2 x Fe x (SO 4) 3 (NFSO- x , 1.5 ≤ x ≤ 2.0) materials such as Na 2 Fe 2 (SO 4) 3 , Na 2 Fe 1.5 (SO 4) 3 , and Na 2.4 Fe 1.8 (SO 4) 3 for sodium storage, the phase and structure characteristics on these NFSO- x are still controversial, making it difficult to achieve phase-pure materials with optimal electrochemical properties. Herein, six NFSO- x samples with varied x are investigated via both experimental methods and density functional theory calculations to analyze the phase and structure properties. It reveals that a pure phase exists in the 1.6 ≤ x ≤ 1.7 region of the NFSO- x , and part of Na ions tend to occupy Fe sites to form more stable frameworks. The NFSO-1.7 exhibits the best electrochemical performance among the NFSO- x samples, delivering a high discharge capacity (104.5 mAh g−1 at 0.1 C, close to its theoretical capacity of 105 mAh g−1), excellent rate performance (81.5 mAh g−1 at 30 C), and remarkable cycle stability over 10,000 cycles with high-capacity retention of 72.4%. We believe that the results are useful to clarify the phase and structure characteristics of polyanionic materials to promote their application for large-scale energy storage. [ABSTRACT FROM AUTHOR]