Dual-doped graphene-based electrode materials for energy devices

Heteroatom co-doping of graphene-based materials has become an effective and powerful approach to develop advanced two-dimensional (2D) layered electrodes by engineering the electronic structure, defect chemistry, and surface functionality for electrochemical energy storage and conversion. Compared with single-atom doping, co-doping enables synergistic modulation of charge redistribution, adsorption energetics, and ion transport behavior through complementary electronic and structural effects. Co-doping enables enhanced ion adsorption, charge transfer, and catalytic activity by introducing specific electronic and structural modifications that increase electrical conductivity, generate numerous active sites, and improve surface wettability. This review article systematically outlines the advantages of co-doped 2D graphene-based materials, and summarizes the synthesis techniques for nitrogen-sulfur (N,S), boron-nitrogen (B,N), nitrogen-phosphorus (N,P), and nitrogen-fluorine (N,F) co-doped 2D graphene-based materials, covering high-temperature annealing, thermal heating, hydrothermal, solvothermal, and liquid-phase methods for dual-heteroatom insertion in the carbon skeleton of these materials. The effectiveness of co-doped 2D graphene-based composite electrodes has been demonstrated in supercapacitors (SCs), batteries, fuel cells, solar cells, and water-splitting applications, highlighting the significance of synergistic heteroatom interactions for improving electrochemical performance. In addition to comparisons between single-doped and co-doped 2D graphene-based materials, analytical insights into electron/ion transport, adsorption energy optimization, and structural stability are discussed. The article provides an outlook for further research, highlighting potential uses and new developments in co-doped graphene-based 2D materials for energy applications. Important issues like scalable synthesis, reproducibility, and long-term cycling stability are also addressed, with suggestions for the systematic design of next-generation graphene-based materials and devices. • Synergistic dual-doping effectively modulates graphene electronic structure • Dual-doping enhances defect chemistry and surface reactivity of graphene • Design principles govern synergistic effects in dual-doped graphene materials • Mechanistic insights explain performance gains in energy storage and conversion • Dual-doped graphene is promising for batteries, supercapacitors and energy devices