Amorphization triggers highly reversible intercalation chemistry in vanadium tetrasulfide for ultrafast aqueous zinc batteries

Abstract

Vanadium tetrasulfide (VS₄) with abundant inter-chain ion storage sites and cationic and anionic redox centers represents a promising cathode for aqueous zinc ion batteries. However, traditional crystalline VS₄ (c-VS₄) undergoes irreversible water-participated conversion reactions during cycling, leading to a short lifespan. Herein, we propose a phase amorphization strategy to modulate the conversion reaction of VS₄ into highly reversible and fast intercalation chemistry. Specifically, the as-prepared amorphous VS₄ (a-VS₄) features highly exposed hydrophobic sulfur atoms, avoiding water-participated irreversible conversion and enabling reversible H⁺/Zn²⁺ co-(de)intercalation. Simultaneously, the loosely-packed structure of a-VS₄ contributes to its isotropic nature and reduced bond energies, facilitating efficient electron and ion transport. Consequently, a-VS₄ renders a high capacity of 324 mAh g⁻¹ at 0.1 A g⁻¹, an impressive rate capability of 111 mAh g⁻¹ at 40 A g⁻¹, and outstanding stability with 93.7 % capacity retention after 8500 cycles, far surpassing those of c-VS₄ and previously reported VS₄ cathodes. Our results offer a new avenue for boosting the zinc storage performance of metal sulfide cathodes.