ALD-Engineered ZnO Gradient-Doped Coating for Enhanced Carbon Compatibility and Stability of Nickel-Rich Cathodes

Nickel-rich layered oxide cathodes (NCMs) face critical challenges, including structural degradation and inadequate rate capability, limiting their application in high-energy lithium-ion batteries. Although carbon coating is a promising strategy to concurrently enhance electronic conductivity and interfacial stability for many different types of electrode materials, conventional coating approaches suffer from detrimental interfacial reactions between carbon precursors and NCMs. Here, we systematically investigate the reaction behavior between NCMs and carbon sources and propose a gradient doping and carbon coating hybrid surface architecture. We found that a conformal ZnO interlayer deposited by ALD, which subsequently undergoes partial transformation into a Zn2+ gradient-doped layer during postannealing, effectively suppresses deleterious interfacial reactions between NCMs and carbon precursors. The modified cathode (CZ-NCM) achieves exceptional capacity retention (99.6% after 100 cycles) and superior rate capability (166.3 mAh/g at 5C). This work presents a practical strategy to minimize detrimental interfacial reactions between a reductive carbon precursor and an oxidative oxide cathode, providing a promising avenue to construct multifunctional interfaces for high-voltage cathodes.