Structural Engineering of Nitrogen-Doped Reduced Graphene Oxide for High-Performance Lithium-Ion Batteries: An Experimental and Theoretical Study

Nitrogen-doped reduced graphene oxide (NrGO) has attracted significant attention due to its potential applications in energy storage devices. Using a combined experimental and computational approach, we investigated the electrochemical performance of NrGO as an anode material for advanced next-generation lithium-ion batteries. The single-pot hydrothermal method was used to achieve different N doping in reduced graphene oxide with various urea concentrations (0.5 g (7.55 at. %), 1.0 g (8.13 at. %), and 1.5 g (10.76 at. %)). The electrode prepared with 1.0 g urea and graphene oxide (1.0NrGO sample) exhibits the highest specific capacity of 585 mA h g–1 at 0.05 C, significantly surpassing pristine commercial graphene oxide (301 mA h g–1). The 1.0NrGO sample exhibits an excellent 92% capacity retention against the 34.7% retention of GO at 0.5 C over 300 cycles. Our first-principles calculations revealed that nitrogen enhances conductivity and the capacity for lithium-ion adsorption. However, excessive oxygen functional groups impede ion diffusion by inducing side reactions and forming barriers along Li-ion pathways. The nitrogen doping and reduced oxygen content are responsible for optimal conductivity, adsorption strength, and Li-ion mobility. Our experimental and theoretical insights pave the way for strategic insights into designing high-capacity and durable GO-based anodes for energy storage systems.