Search

Owing to the advantages of high safety, low cost, high theoretical volumetric capacities, and environmental friendliness, magnesium-ion batteries (MIBs) have more feasibility for large-scale energy storage compared to lithium-ion batteries. However, lack of suitable cathode materials due to sluggish kinetics of magnesium ion is one of the biggest challenges. Herein, water-pillared sodium vanadium bronze nanowires (Na2 V6 O16 ·1.63H2 O) are reported as cathode material for MIBs, which display high performance in magnesium storage. The hydrated sodium ions provide excellent structural stability. The charge shielding effect of lattice water enables fast Mg2+ diffusion. It exhibits high specific capacity of 175 mAh g-1 , long cycle life (450 cycles), and high coulombic efficiency (≈100%). At high current density of 200 mA g-1 , the capacity retention is up to 71% even after 450 cycles (compared to the highest capacity), demonstrating excellent long-term cycling performance. The nature of charge storage kinetics is explored. Furthermore, a highly reversible structure change during the electrochemical process is proved by comprehensive electrochemical analysis. The remarkable electrochemical performance makes Na2 V6 O16 ·1.63H2 O a promising cathode material for low-cost and safe MIBs.

The increasing demands for renewable energy to substitute traditional fossil fuels and related large-scale energy storage systems (EES) drive developments in battery technology and applications today. The lithium-ion battery (LIB), the trendsetter of rechargeable batteries, has dominated the market for portable electronics and electric vehicles and is seeking a participant opportunity in the grid-scale battery market. However, there has been a growing concern regarding the cost and resource availability of lithium. The sodium-ion battery (SIB) is regarded as an ideal battery choice for grid-scale EES owing to its similar electrochemistry to the LIB and the crust abundance of Na resources. Because of the participation in frequency regulation, high pulse-power capability is essential for the implanted SIBs in EES. Herein, a comprehensive overview of the recent advances in the exploration of high-power cathode and anode materials for SIB is presented, and deep understanding of the inherent host structure, sodium storage mechanism, Na+ diffusion kinetics, together with promising strategies to promote the rate performance is provided. This work may shed light on the classification and screening of alternative high rate electrode materials and provide guidance for the design and application of high power SIBs in the future.