We report an aqueous Zn−V 2 O 5 battery chemistry employing commercial V 2 O 5 cathode, Zn anode, and 3 M Zn(CF 3 SO 3 ) 2 electrolyte. We elucidate the Zn-storage mechanism in the V 2 O 5 cathode to be that hydrated Zn 2+ can reversibly (de)intercalate through the layered structure. The function of the cointercalated H 2 O is revealed to be shielding the electrostatic interactions between Zn 2+ and the host framework, accounting for the enhanced kinetics. In addition, the pristine bulk V 2 O 5 gradually evolves into porous nanosheets upon cycling, providing more active sites for Zn 2+ storage and thus rendering an initial capacity increase. As a consequence, a reversible capacity of 470 mAh g −1 at 0.2 A g −1 and a long-term cyclability with 91.1% capacity rentention over 4000 cycles at 5 A g −1 are achieved. The combination of the good battery performance, safety, scalable materials synthesis, and facile cell assembly indicates this aqueous Zn−V 2 O 5 system is promising for stationary grid storage applications.

Rechargeable aqueous zinc batteries have gained considerable attention for large‐scale energy storage systems because of their low cost and high safety, but they suffer from limitations in cycling stability and energy density with advanced cathode materials. Here, a high‐performance V5O12·6H2O (VOH) nanobelt cathode uniformly located on a stainless‐steel substrate via a facile electrodeposition technique is reported. We show that the hydrated layered VOH cathode enables highly reversible and ultrafast Zn2+ cation (de)intercalation processes, as confirmed by various electrochemical, X‐ray diffraction, X‐ray photoelectron spectroscopy, and transmission electron microscopy analyses. It is demonstrated that the binder‐free VOH cathode can deliver a discharge capacity of 354.8 mAh g−1 at 0.5 A g−1 with a high initial Coulombic efficiency of 99.5%, a high energy density of 194 Wh kg−1 at 2100 W kg−1, and a long cycle life with a capacity retention of 94% over 1000 cycles. In addition, a flexible quasi‐solid‐state Zn–VOH battery is constructed, achieving a reversible capacity of ≈300 mAh g−1 with a capacity retention of 96% after 50 cycles and displaying excellent electrochemical behaviors under different bending states. This work sheds light on the development of rechargeable aqueous zinc batteries for stationary grid storage applications or flexible energy storage devices.

Ultrasmall Sn nanodots (1-2 nm) are homogeneously encapsulated in porous N-doped carbon nanofibers using a simple and scalable electrospinning method. The composite nanofibers weave into flexible free-standing membrane and can be directly used as binder- and current collector-free anode for Na-ion batteries, exhibiting excellent electrochemical performance with high reversible capacity, exceptional rate capability, and ultralong cycle life.

This review summarizes the recent progress and remaining challenges of polyanion-type cathodes, providing guidelines towards high-performance cathodes for sodium ion batteries.

Designed as a high‐capacity, high‐rate, and long‐cycle life anode for sodium‐ion batteries, ultrasmall Sn nanoparticles (≈8 nm) homogeneously embedded in spherical carbon network (denoted as 8‐Sn@C) is prepared using an aerosol spray pyrolysis method. Instrumental analyses show that 8‐Sn@C nanocomposite with 46 wt% Sn and a BET surface area of 150.43 m2 g−1 delivers an initial reversible capacity of ≈493.6 mA h g−1 at the current density of 200 mA g−1, a high‐rate capacity of 349 mA h g−1 even at 4000 mA g−1, and a stable capacity of ≈415 mA h g−1 after 500 cycles at 1000 mA g−1. The remarkable electrochemical performance of 8‐Sn@C is owing to the synergetic effects between the well‐dispersed ultrasmall Sn nanoparticles and the conductive carbon network. This unique structure of very‐fine Sn nanoparticles embedded in the porous carbon network can effectively suppress the volume fluctuation and particle aggregation of tin during prolonged sodiation/desodiation process, thus solving the major problems of pulverization, loss of electrical contact and low utilization rate facing Sn anode.

This review is focused on the recent progress and strategies in the fabrication of high performance anode materials for Na-ion batteries.

Data openly available in a public repository that does not issue DOIs.

To develop a long cycle life and good rate capability electrode, 3D hierarchical porous α-Fe 2 O 3 nanosheets are fabricated on copper foil and directly used as binder-free anode for lithium-ion batteries. This electrode exhibits a high reversible capacity and excellent rate capability. A reversible capacity up to 877.7 mAh g −1 is maintained at 2 C (2.01 A g −1 ) after 1000 cycles, and even when the current is increased to 20 C (20.1 A g −1 ), a capacity of 433 mA h g −1 is retained. The unique porous 3D hierarchical nanostructure improves electronic-ionic transport, mitigates the internal mechanical stress induced by the volume variations of the electrode upon cycling, and forms a 3D conductive network during cycling. No addition of any electrochemically inactive conductive agents or polymer binders is required. Therefore, binder-free electrodes further avoid the uneven distribution of conductive carbon on the current collector due to physical mixing and the addition of an insulator (binder), which has benefi ts leading to outstanding electrochemical performance.