Coating technologies for battery active materials

The widespread deployment of rechargeable batteries is central to the global transition towards clean energy, yet their long-term stability remains a challenge. Electrode degradation, manifested through interfacial reactions, structural disorder and gas evolution, elevates internal resistance, accelerates capacity loss and complicates recycling. Surface coatings can stabilize electrode–electrolyte interfaces, suppress parasitic reactions and enhance structural resilience. In this Review, we survey coating technologies for high-energy battery active materials, including nickel-rich (nickel content ≥60%) cathodes, graphite and silicon anodes, and lithium metal. Wet-chemical approaches offer strong compositional tunability and compatibility with scalable manufacturing; gas-phase methods enable nanometre-scale, ultrathin and highly conformal interfacial control; solid-state strategies provide solvent-free processing pathways; and emerging methods enable rapid and multifunctional coating routes across a broader range of material and process conditions. The industrial adoption of these coating technologies depends on balancing electrochemical gains with process scalability, cost and recycling compatibility. Future progress will rely on multifunctional and adaptive coatings, in situ process monitoring and green chemistries to support durable and circular battery systems.