Boosting the zinc storage performance of sodium vanadate cathodes via V-alloyed MXene

This study develops high-performance zinc-ion battery cathodes through dual engineering of vanadium-alloyed MXene and its heterointerface with sodium vanadate (NaV 3 O 8 ·1.5H 2 O, NVO). By selectively etching (Ti 1-x V x ) 3 AlC 2 MAX precursors (NaF/HCl, 60℃, 48 h), we synthesized (Ti 1-x V x ) 3 C 2 MXene solid solutions where V-substitution optimizes electron conductivity. When composited with NVO, the 20 wt% (Ti 0.7 V 0.3 ) 3 C 2 /NVO cathode delivers remarkable specific capacities of 221.6 mA h g −1 at 10 A g −1 – surpassing pure NVO by 4.0-fold and Ti 3 C 2 /NVO by 2.5-fold – and maintains 195 mA h g −1 after 5,000 cycles (1.7 times of pure NVO and 4.1 times Ti 3 C 2 /NVO), outperforming state-of-the-art vanadate cathodes. Mechanistic analysis reveals that while NVO enables reversible Zn 2+ redox reaction, the V-alloyed MXene simultaneously constructs a 3D conductive network suppressing electrode degradation and creates low-energy Zn 2+ migration channels at interfaces via lattice distortion. Collectively, this interface engineering strategy unlocks ultra-stable zinc storage at practically high rates (10 A g −1 ), providing a pathway for next-generation zinc storage cathode.