Metal-Semiconductor Ohmic and Schottky Contact Interfaces for Stable Li-Metal Electrodes

Abstract

Li-metal is an attractive anode material for next-generation batteries owing to its high capacity and low reduction potential. Unfortunately, it undergoes dendritic growth, which limits its development. Herein, amorphous polymeric carbon-based semiconducting passivation layers are applied to Li-metal electrodes using radiofrequency plasma thermal evaporation to suppress dendrite growth. The plasma power is controlled to adjust the semiconducting type and mechanical properties of the plasma-polymerized carbon layer (PCL). n- and p-type semiconducting PCLs (n- and p-PCLs) form ohmic and Schottky contacts, respectively, with the Li-metal. p-PCL was more effective than n-PCL at suppressing Li-dendrite formation, as the former enhanced the modulus and Li-ion conductivity, inducing Li-ion deposition below the passivation layer. The p-PCL-coated Li electrode maintains state-of-the-art stable dendrite-free cycling behavior with overpotentials of ∼11.10 and ∼79.84 mV over 16 »450 and 2472 h at 1 and 10 mA cm-2, respectively.