Atomic layer deposited Ru/Mo2C heterostructure for efficient nitrogen reduction and nitrogen evolution in Li-N2 battery

• Controllable fabrication of metal-support structure by atomic layer deposition. • Modulation of electronic transfer by the construction of Ru/Mo 2 C heterostructure. • Ru/Mo 2 C heterostructure promotes the kinetics of the NRR and NER in Li-N 2 battery. • Ru/Mo 2 C significantly improves the electrochemical performance of Li-N 2 battery. Li-N 2 battery is a promising platform for integrating N 2 fixation and electrochemical energy storage. However, the low activity and poor stability of cathode catalysts lead to undesirable electrochemical performance of Li-N 2 batteries. Herein, a Ru/Mo 2 C heterostructure was controllably fabricated on N-doped carbon nanotubes (NCNTs) by atomic layer deposition technique. The Li-N 2 battery with Ru/Mo 2 C-NCNTs cathode catalyst exhibits large specific capacity, high cycling stability and enhanced reversibility. This excellent performance derives from the formation of unique Ru/Mo 2 C heterostructure by the preferential deposition of Ru on Mo 2 C supports with a controlled number of ALD-cycles, which could enrich the active sites, improve the structural stability and modulate the electronic transfer behavior to facilitate N 2 reduction reaction and N 2 evolution reaction on the cathode. This work may provide a new direction or strategy for the development of efficient cathode electrocatalysts for Li-N 2 batteries.