Multi-Functional Mo-Ion interlayer engineering facilitates high performance aqueous zinc-ion batteries

Abstract

The widespread application of vanadium oxide cathodes in aqueous zinc-ion batteries (AZIBs) remains constrained by three fundamental limitations: structural dissolution in electrolyte media, inadequate electronic conductivity, and sluggish Zn²⁺ diffusion kinetics. To concurrently overcome these challenges, we engineered Mo-intercalated V₃O₇ cathodes (denoted as Mo_0.06V₃O₇) through strategic interlayer modification. This multifunctional design achieves: enhanced structural integrity through interlayer stabilization, improved charge transfer capability, and optimized Zn²⁺ transport pathways with reduced diffusion energy barriers. The optimized cathode delivers a specific capacity of 460 mAh g⁻¹ at 0.2 A g⁻¹ and demonstrates exceptional cyclability with 91.8 % capacity retention after 20,000 cycles at 10 A g⁻¹. Notably, temperature-dependent testing confirms stable operation across -20 to 40 °C, addressing a critical limitation in practical deployment scenarios. Density functional theory (DFT) calculations reveal three synergistic mechanisms: Mo intercalation strengthens V-O bonding (3.1 double bond energy increase), simultaneously modulating charge redistribution during Zn²⁺ insertion and effectively reducing electrostatic interactions between zinc ions and host framework (2.5 double diffusion barrier decrease). This interlayer engineering strategy establishes a materials design paradigm applicable to diverse vanadium oxide systems, potentially accelerating the development of high-performance AZIB for grid-scale energy storage applications.