Polarity Index‐Guided Screening for Interfacial Molecular Enrichment Enabling Stable Zinc Metal Anodes

ABSTRACT

Functional additives enrichment within protective coatings represents a promising strategy for stabilizing zinc anode. However, selecting suitable additive molecules remains challenging due to required multifunctional adsorption capability. Herein, this work proposes the comprehensive consideration of polarity parameters for selecting functionally enriched additives within coatings, particularly the polar surface area (PSA) and PSA ratio as highly pertinent descriptors. As a validation, N‐methylformamide (NMF), with high PSA (82.39 Å ² ) and PSA ratio (80.13%), provides thermodynamically favorable sites for interaction between kaolinite (KL) and Zn ²⁺ . NMF enables a stable and energetically favorable arrangement within the kaolinite interlayer for enhanced electric field regulation capability and efficient ion transport, thus simultaneously achieving stable interface and fast kinetics. The KL‐NMF@Zn symmetric cell cycle stably for over 1000 h at 1 mAh cm ⁻² and 150 h at 10 mAh cm ⁻² (∼57% DOD). The NH ₄ V ₄ O ₁₀ ||KL‐NMF@Zn full cell retains 165.9 mAh g ⁻¹ after 400 cycles at 1 A g ⁻¹ (N/p = 3.22). The 300‐mAh pouch cell cycle steadily for 200 cycles at 3 mAh cm ⁻² , highlighting the practical potential. This work provides a novel concept utilizing comprehensive polarity parameters for scalable interfacial engineering toward durable aqueous zinc metal batteries.