Enhanced Kinetics over VS4 Microspheres with Multidimensional Na+ Transfer Channels for High-Rate Na-Ion Battery Anodes.

Abstract

Developing 3 D self-assembled nanoarchitectures with well-defined crystal structures is an effective strategy to enhance the electrochemical performances of electrode materials. (1 1 0)-oriented and bridged-nanoblocks self-assembled VS4 microspheres are controllably synthesized by a facile one-step hydrothermal method. The (1 1 0)-bridged structure sets up open pathways for Na+ diffusion among nanoblocks, and the (1 1 0)-oriented structure provides unobstructed pathways for Na+ diffusion in the nanoblocks, which collectively constructs multidimensional Na+ transfer channels in the VS4 microspheres, promoting the electrochemical kinetics. As an anode for Na-ion batteries (SIBs), this material exhibits pseudocapacitive Na+ storage and excellent rate capability, delivering high capacities of 339 and 270 mAh g-1 at rates of 0.1 and 2.0 A g-1 , respectively, with a capacity retention of 79 % in the voltage window of 0.5-3.0 V. In particular, the reversible capacity reaches 575 mAh g-1 after 300 cycles even at 1.0 A g-1 in the voltage window of 0.05-3.0 V, outperforming those of the ever-reported VS4 -based anode materials. This work presents an effective strategy to the exploration and design of high-performance anodes for SIBs.