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Although sodium ion batteries (SIB) have shown great potential for large-scale energy storage systems, the development of high-performance anode materials for SIB is crucial for their progress. However, the cycling performance of SIB is currently limited by severe volume changes during the sodiation/desodiation process. To overcome this problem, a bi-active metal alloying strategy has been proposed. In this study, we utilized pulsed electrodeposition to prepare bismuth-antimony alloy anode materials. The resulting Bi 44.9 Sb 55.1 alloy anode exhibited exceptional specific capacity, rate performance, and stability. After the second cycle, the discharge/charge capacities were 505.3 mAh·g−1/496.7 mAh·g−1 at 1 A·g−1, with a coulombic efficiency of over 98 %. Even after 50 cycles, the capacities remained at 494.7 mAh·g−1/481.9 mAh·g−1 with a capacity retention rate of 97.9 %. These excellent properties were attributed to the stable structure and suitable voids for electron transport and ion diffusion in the Bi 44.9 Sb 55.1 alloy, which effectively mitigated volume expansion during cycling. The reaction kinetics and mechanism were studied using cyclic voltammetry, in situ X-ray diffraction, and nuclear magnetic resonance techniques. Our work provides valuable insights for the development of bi-active metal alloy anodes for SIB. [ABSTRACT FROM AUTHOR]

To explore high performance anodes remains a key challenge for rechargeable Na-ion batteries (NIBs). In this work, we predict that layered molybdenum dinitride (MoN 2 ) could be a promising anode material for NIBs by first-principle calculations. The results show that each formula unit of MoN 2 monolayer can accommodate four Na atoms, corresponding to a high specific capacity of 864 mA h g −1 . The average open circuit voltage is estimated to be 0.62 V, benefitting for a high open voltage of a full cell. The diffusion barrier for Na on MoN 2 monolayer is quite small as 0.12 eV, indicating an excellent rate capability. Moreover, the Na atoms prefer to adsorb on MoN 2 monolayer separately with each other, which is essentially important for remaining high performance during cycling. Our results show that the layered MoN 2 has great potential to be an excellent anode material for NIBs. [ABSTRACT FROM AUTHOR]

Alloy anodes are widely recognized for their high theoretical specific capacity and have garnered significant attention among the anode materials studied for sodium-ion batteries. In this study, we synthesize Cu 68.6 Sb 23.0 Sn 3.2 Zn 0.3 P 4.9 anodes using a double-pulse electrodeposition method. This binder-free alloy anode, comprising five high-capacity elements, significantly enhances specific capacity and improves cycling stability, while also demonstrating excellent sodium storage capability. Specifically, the Cu 68.6 Sb 23.0 Sn 3.2 Zn 0.3 P 4.9 anode achieves an initial charge capacity of 368.8 mAh∙g−1 and remains highly stable over 100 cycles, with a capacity decay of only 0.1 %. In addition, the anode delivers 290.3 mAh∙g−1 even at a current density of 3200 mA∙g−1. The outstanding electrochemical performance can be attributed to improved electronic transfer efficiency due to the introduction of Cu into Cu 68.6 Sb 23.0 Sn 3.2 Zn 0.3 P 4.9 alloy via reverse potential, as well as the porous structure that facilitates electrolyte penetration and sodium ion transport. The galvanostatic intermittent titration technique reveals a high sodium ion diffusion coefficient, further highlighting the potential of this alloy anode in advancing sodium-ion batteries. [Display omitted] • Double-pulse electrodeposition is a novel method to prepare alloy anode materials to improve sodium storage performance. • Introducing reverse voltage deposition of copper enhances the electronic conductivity of the alloy and accelerates charge delocalization. • Special Porous structure facilitates electrolyte permeation and sodium ion transport to improve electrochemical performance. [ABSTRACT FROM AUTHOR]

Sodium-ion batteries (SIBs) have garnered significant attention as cost-efficient and expandable energy conversion devices. Nonetheless, their further utilization is impeded by the rapid deterioration in the capacity of anode materials during cycling. Herein, we have successfully introduced both active (Zn) and non-active (Cu) metal components into Sb by fabricating Cu-doped Sb-Zn (SZC-N) anodes through a template-free novel pulse potential electrodeposition (NPPED) approach. The introduction of Cu demonstrated a crucial role in directing the formation of the uniform structure. On the other hand, active "Zn" increases overall capacity and serves as a cushion against the volume expansion of Sb. Notably, the SZC-N exhibits enhanced charge diffusion while maintaining the structural integrity of the electrode, making it a promising choice for SIBs. Interestingly, the SZC-N electrode demonstrated remarkable cycling and rate performance, manifesting an excellent reversible capacity of 380.9 mAh·g−1 after 250 cycles, with an outstanding capacity retention of 80 % when operated at 1 C. Furthermore, it achieved a noteworthy capacity of 454.1 mAh·g−1 at a high current density of 10 C. In contrast, both the SZC-R and SZ-C anodes only yielded 52.9 and 3.9 mAh·g−1 (after 250 cycles), moreover, delivering inferior rate performance. The increased cyclic performance of the SZC-N electrode can be ascribed to the presence of a Cu network, which facilitates charge transport and promotes the stabilization of the electrode structure. The findings suggest that binder-free anode materials produced through the NPPED method present a promising opportunity for SIBs. For the first time, we have successfully introduced both active and non-active metal components into Sb by fabricating SZC-N anodes through a template-free NPPED methodology. The introduction of "Cu" played a crucial role in directing the formation of the uniform structure. On the other hand, active "Zn" increases overall capacity and acts as a buffer against the volume expansion of Sb. Notably, the Cu-doped network in Sb-Zn anodes exhibits enhanced charge diffusion while maintaining the structural integrity of the anode materials, making it a promising candidate for SIBs. Interestingly, the SZC-N anode demonstrated remarkable cycling and rate performance, manifesting an excellent reversible capacity of 380.9 mAh·g−1 after 250 cycles, with an outstanding capacity retention of 80 % when operated at 1 C. Furthermore, it achieved a noteworthy capacity of 454.1 mAh·g−1 at a high current density of 10 C. In contrast, both the SZC-R and SZ-C anodes only yielded 52.9 and 3.9 mAh·g−1 (after 250 cycles), moreover, delivering inferior rate performance. The improved cyclic performance of the SZC-N anode materials can be attributed to the existence of a Cu network, which facilitates charge transport and promotes the stabilization of the electrode structure. The results indicate that binder-free anode materials fabricated by NPPED offer a potential opportunity for the application of SIBs. [Display omitted] [ABSTRACT FROM AUTHOR]

• The guiding effect of Cu makes anode form the hierarchical paddy-like structure. • The paddy-like structure can mitigate volume expansion-related stress. • The highly conducting Cu ensures the stability of the electrode structure. • The PRPED represents a promising approach for producing innovative binder-free anode. Sodium-ion batteries (SIBs) have gained remarkable interest as cost-effective and scalable energy storage devices. Nevertheless, their further application has been significantly hindered due to the limited selection of desirable anode materials that can provide both high capacity and excellent cycling stability. Herein, we developed a hierarchical paddy-like Bi 42.3 Sb 35.2 Cu 22.5 alloy anode on Cu foil via template-free pulse reverse potential electrodeposition. The Bi 42.3 Sb 35.2 Cu 22.5 anode obtains a considerable specific capacity of 529.5 mAh·g−1 after 120 cycles with a remarkable capacity retention of 95.5 %, signifying a capacity loss of only 0.0375 % per cycle. However, Bi 44.9 Sb 55.1 anodes obtained by the pulse potential electrodeposition strategy reveal a conventional irregular cluster structure, delivering only 64.5 mAh·g−1 after 100 cycles and also demonstrating inferior rate performance compared to Bi 42.3 Sb 35.2 Cu 22.5 anodes. The enhanced cycling performance of the paddy-like Bi 42.3 Sb 35.2 Cu 22.5 anode is primarily attributed to the introduced Cu-doped network facilitating the rapid diffusion of Na+ and also ensuring the stability of the electrode structure. Moreover, the unique paddy-like structure of Bi 42.3 Sb 35.2 Cu 22.5 mitigates volume expansion-related stress and facilitates efficient charge transport through open channels. This is further corroborated by conducting CV measurements, indicating a greater capacitive contribution in the case of the Bi 42.3 Sb 35.2 Cu 22.5 electrode compared to the Bi 44.9 Sb 55.1 electrode. Additionally, SEM images show a stabilized surface morphology for the Bi 42.3 Sb 35.2 Cu 22.5 electrode after cycling, demonstrating improved electrochemical performance. This work offers new insights into the development of high-performance anode materials for SIBs. [ABSTRACT FROM AUTHOR]

[Display omitted] • High capactities and low volume changes. • Low energy barriers for Mg and Al ions transportation. • High and stable electrical conductivity. Mg-ion batteries and Al-ion batteries are considered as potential replacements for Li-ion batteries due to their high-volumetric-capacity. The search for high-performance anode materials with a fast and reversible insertion of Mg/Al-ions remains a major challenge. In this study, the potential applications of a 3D topological metal boron structure (H-boron) as anode materials for MIBs/AIBs have been studied using the first-principle method. Their ultrahigh maximum capacities are 2480 and 5114 mAh/g for Mg/Al with small volume changes. The diffusion barriers are 0.34 and 0.35 eV for Mg/Al in H-boron. Above results demonstrate that H-boron can be a promising MIBs/AIBs anode. [ABSTRACT FROM AUTHOR]