Volmer–Weber growth of nano-island heterostructures on spinel cathodes: a route to stable high-voltage lithium-ion batteries

Engineering stable electrode-electrolyte interfaces is paramount for the operation of high-voltage lithium-ion batteries. Here, we demonstrate the spontaneous formation of a uniform zirconia nano-island architecture on 5V-class spinel crystallites by introducing a trace zirconium precursor. This phenomenon, rationalized as a Volmer-Weber growth mechanism, is thermodynamically driven by the immiscibility of Zr and a large lattice mismatch (∼10%) between the surface-templated cubic ZrO₂ and the spinel substrate, which prevents further coalescing into large aggregates or a continuous film. Crucially, this discrete nano-island architecture offers a unique solution to a long-standing coating dilemma, overcoming the transport-blocking nature of pinhole-free films whilst offering comprehensive surface protection. It simultaneously enhances surface conductivity and stability as well as anchors a robust cathode-electrolyte interphase. As a result of this multifunctional interface, the optimized cathode exhibits outstanding electrochemical stability, retaining 90.8% of its capacity after 1000 cycles in half-cells and 77.5% after 500 cycles in pouch cells paired with graphite anodes.