Data-Driven Cation Engineering Guides Electrolyte Design for Sustainable Aqueous Zinc Battery Chemistries

Vanadium oxides have emerged as attractive cathode materials for zinc-based batteries owing to their high theoretical capacity and versatile redox chemistry. Nevertheless, their persistent dissolution in aqueous electrolytes remains a long-standing challenge, hindering real-world implementation. Here, we develop a cation-engineered electrolyte strategy enabled by a data-driven framework that integrates density functional theory (DFT) calculations, discrete wavelet transform (DWT)-based multi-scale analysis, and differential feature extraction, to efficiently screen potential hetero-cations and their combinations with objective statistic quantification, while minimizing trial-and-error experimentation and selection bias. As a proof of concept, the Zn/VOx batteries with the predicted Na⁺-Mg²⁺-Zn²⁺ tri-cation electrolyte (NMZ) achieved exceptional reversibility and record-long cycling stability, sustaining 500 cycles at 0.2 A g^-1 (1400 h) and 10,000 cycles at 5 A g^-1. The tri-cation electrolyte successfully triggers a potential-driven sequential ion insertion pathway involving Na⁺, Mg²⁺, and Zn²⁺, thereby fundamentally suppressing proton intercalation above 1.3 V and hydrated Zn²⁺ insertion near 1.0 V (vs Zn²⁺/Zn). This work not only provides valuable data-driven insights into ion-engineering electrochemistry for regulating insertion stability but also uncovers critical ion-related factors that are frequently overlooked. This approach establishes a reusable and statistically robust framework for guiding research across diverse battery chemistries.