Surface modification has been widely considered as an effective strategy to boost cycle-life and enhance conductivity of electrode particles for lithium ion batteries (LIBs). Atomic layer deposition (ALD) is a layer-by-layer thin film coating technique. Through ALD, a conformal ultrathin coating with controllable thickness can provide initial protection for surface of active materials. Recently, we studied cerium dioxide (CeO₂) and iron oxide as conductive coating materials for LIB application. Both CeO₂ and iron oxide can significantly enhance the electrochemical performance of LIB electrode materials. For example, iron oxide films were coated on LiMn_1.5Ni_0.5O₄ particles by ALD for the synergetic effect of performance enhancing by iron doping and conformal iron oxide film coating. With an optimal film thickness of ~0.6 nm, the initial capacity improved by 25% at room temperature and by ~26% at 55 °C at a 1C cycling rate. The synergy of doping of LiMn_1.5Ni_0.5O₄ with Fe near surface combined with the conductive and protective nature of the optimal iron oxide film led to high capacity retention (~93% at room temperature and ~91% at 55 °C) even after 1,000 cycles at a 1C cycling rate.