From compositional tuning to structural design: Advancing cathode catalysts for high-performance Li–CO2 batteries

ABSTRACT The lithium–carbon dioxide (Li–CO 2 ) battery presents a promising technology for high-energy storage and CO 2 utilization. However, its practical application is hindered by high charge overpotentials and poor reversibility, primarily owing to the difficulty in decomposing solid discharge products. The cathode catalyst plays a decisive role in overcoming these challenges. This review provides a systematic and forward-looking analysis of recent advances in cathode catalyst design, emphasizing the critical integration of two complementary dimensions: compositional tuning and structural engineering. Compositional tuning, including doping, defect engineering, alloying/high-entropy effects, heterointerface construction, and surface functionalization, optimizes the electronic structure and intrinsic activity of catalytic sites. Structural engineering, through porosity design, nanosizing, morphology control, and dimensionality integration, maximizes active site accessibility, mass transport, and mechanical stability. We highlight that the synergistic integration of these strategies, rather than their isolated application, is key to achieving breakthrough performance in activity, selectivity, and durability. Furthermore, we discuss future directions, underscoring the need for in-situ mechanistic understanding, multi-scale rational design, stability under practical operating conditions, and holistic cell integration. By framing catalyst development as a coordinated compositional–structural optimization problem, the aim of this review is to guide the rational design of next-generation cathodes for efficient, stable, and practical Li–CO 2 energy storage systems.