Vapor-Phase Atomic-Controllable Growth of Amorphous Li2S for High-Performance Lithium–Sulfur Batteries

Lithium–sulfur (Li–S) batteries hold great promise to meet the formidable energy storage requirements of future electrical vehicles but are prohibited from practical implementation by their severe capacity fading and the risks imposed by Li metal anodes. Nanoscale Li2S offers the possibility to overcome these challenges, but no synthetic technique exists for fine-tailoring Li2S at the nanoscale. Herein we report a vapor-phase atomic layer deposition (ALD) method for the atomic-scale-controllable synthesis of Li2S. Besides a comprehensive investigation of the ALD Li2S growth mechanism, we further describe the high performance of the resulting amorphous Li2S nanofilms as cathodes in Li–S batteries, achieving a stable capacity of ∼800 mA·h/g, nearly 100% Coulombic efficiency, and excellent rate capability. Nanoscale Li2S holds great potential for both bulk-type and thin-film high-energy Li–S batteries.