Particle‐Level ZrO ₂ Atomic Layer Deposition Enables Fast‐Cycling and Long‐Life Graphite Cathodes for Dual‐Ion Batteries

ABSTRACT

Fast‐charging and long‐life energy storage systems require electrode architectures that can sustain rapid ion transport while resisting structural and interfacial degradation. Dual‐ion batteries are attractive high‐voltage systems based on reversible anion intercalation into a graphite cathode. However, their long‐term operation is limited by large graphite volume changes, solvent co‐intercalation, unstable cathode‐electrolyte interphase formation, and electrolyte decomposition at high potentials. This study demonstrates that the spatial location of an atomic layer deposition (ALD) coating is a decisive factor in stabilizing graphite cathodes. After identifying ZrO ₂ as an effective coating, electrode‐level ALD and particle‐level ALD were compared using the same coating chemistry. Unlike electrode‐level ALD, which coats the pre‐fabricated composite electrode and covers inactive components, particle‐level ALD directly modifies graphite particles before electrode fabrication. This particle‐level ZrO ₂ coating improves electrode cohesion, preserves electronic connectivity, enriches PF ₆ ⁻ near the graphite interface, and facilitates anion transport. As a result, the particle‐level ALD graphite cathode delivers stable high‐rate cycling for 4000 cycles at a 5 C‐rate. Post‐cycling analyses confirm that particle‐level ZrO ₂ reinforces graphite, suppresses solvent‐assisted structural collapse, and mitigates excessive electrolyte decomposition. This work establishes the scale of coating application, particle‐level versus electrode‐level, as a key design principle for durable graphite cathodes in fast‐cycling dual‐ion batteries.