Bifunctional Electrocatalysts in Rechargeable Lithium‐Gas Batteries: Material Evolution and Mechanistic Insights from Metal‐Free Carbons to Carbon‐Supported Single‐Atom Sites

ABSTRACT Advanced lithium‐gas batteries (LGBs), including Li‐CO ₂ batteries (LCOBs), Li‐O ₂ batteries (LOBs), and Li‐N ₂ batteries (LNBs) systems, offer superior energy density and promising long‐term stability. However, their widespread implementation is hindered by slow gas‐conversion kinetics, causing high overpotentials, low‐rate performance, and limited electrochemical reversibility, which severely affects cycling stability. Addressing these challenges requires designing bifunctional electrocatalysts that enhance both discharge and charge reactions for efficient gas conversion. Carbon‐based metal‐free electrocatalysts (C‐MFECs) and carbon‐supported single‐atom catalysts (CS‐SACs) are highly promising alternatives, distinguished by their outstanding catalytic activity for efficient reactant activation and product decomposition. This review offers an in‐depth analysis of LGBs, discussing the key challenges that hinder gas‐conversion reversibility and emphasizing the origin of bifunctional catalytic activity in C‐MFECs and CS‐SACs. We further explore recent advances in LGB applications, highlighting strategies to improve catalytic efficiency and electrochemical reversibility. Finally, we outline future directions for developing bifunctional C‐MFECs and CS‐SACs, focusing on material innovation, mechanistic insights, and practical implementation to drive the development of sustainable next‐generation LGBs.