Microspherical copper tetrathiovanadate with stable binding site as ultra-rate and extended longevity anode for sodium-ion half/full batteries

Vanadium sulfides are appeared and investigated for the application of sodium-ion batteries (SIBs) due to their adjustable structure and high theoretical capacity. Nevertheless, their inferior sodiation/desodiation kinetics during cycling and convoluted Na+ storage mechanism severely restricts their application in SIBs. Herein, a facile one-step hydrothermal approach is applied to synthesize interconnected and homogeneous Cu3VS4 microspheres with enhanced intrinsic conductivity, which is beneficial for improving electrochemical kinetics and modulation the stress relief. As applied in SIBs, the Cu3VS4 delivers a high capacity of 500 mAh g−1 after 100 cycles at 0.2 A g−1. Impressively, an ultra-stable capacity of 274 mAh g−1 after 25,000 cycles of Cu3VS4 can be achieved at 20 A g−1. The first-principles calculations are detailed given to confirm the sodium storage mechanism and extended longevity of the Cu3VS4. A Na3V2(PO4)2O2F cathode is constructed to assemble the full cell, also exhibiting a magnificent energy density of 171 Wh kg−1 and remarkable cycling stability (5000 cycles). We first time show the comprehensive understanding of superior SIBs performance of Cu3VS4 from both experimental and theoretical perspectives, giving the possibility for the next-generation advanced energy storage device.