In situ grown Nb4N5 nanocrystal on nitrogen-doped graphene as a novel anode for lithium ion battery

Abstract

The metal-rich niobium nitride of Nb₄N₅ has higher conductivity than Nb₃N₅ and a higher theoretical specific capacity than NbN. To rationally design a metal-rich anode material, Nb₄N₅ nanocrystals coated by nitrogen-doped graphene (N-G) have been successfully synthesized by a facile in situ ice bathing method with subsequent annealing in NH₃. The use of these as an anode material is reported for the first time. The discharge capacity is 487 mA h g⁻¹ at the current density of 0.1 A g⁻¹ (0.0819 mA cm⁻²) after 200 cycles and the high rate discharge capacity is 125 mA h g⁻¹ at a current density of 5 A g⁻¹ (4.0926 mA cm⁻²). Specially, the discharge capacity is still enhanced after 200 cycles at 0.1 A g⁻¹ (0.0819 mA cm⁻²). The Nb₄N₅/N-G hybrid could be a promising anode material for LIBs with a high rate performance and long cycle life.