The deployment of nickel-rich layered oxides in cathodes is a game-changer for next-generation lithium-ion batteries, offering impressive energy density and rate capabilities. However, the high nickel content comes with an inherent downside: it induces phase transformations and lattice oxygen loss at the surface due to the presence of more unstable Ni4+ ions, accelerating capacity fade during cycling. This surface reconstruction not only jeopardizes long-term performance but also heightens the risk of mechanical breakdowns due to the rapid build-up of interfacial strain. Current cathode-coating strategies, aimed at mitigating this surface restructuring, struggle to strike a balance between rapid electron/ion transport and maintaining structural integrity, ultimately constraining the technological readiness level of this promising material.

“Lacking consistent Li+ transport channels in the lattice and sufficient cohesive strength at the coating layer/cathode interface is another challenge we attempt to address,” says Xu. The team’s solution is to epitaxially grow the coating layer via oriented attachment of Nb12WO33 and ZrO2 nanocrystals. “We chose Nb12WO33 as a coating precursor because of its ReO3-type motif that aligns well with the lattice of layered structure in [100] direction. This compatibility in lattice enables the oriented attachment-driven surface fusion (cation mixing) under thermal treatment, ultimately leading to seamlessly interconnected lattice channels at the interface,” explains Xu.