Pathway Engineering in Li–CO ₂ Batteries: Mitigating Energy Barriers via Optimized 4e ⁻ /3CO ₂ and 2e ⁻ /2CO ₂ Redox Chemistry

Abstract The Li–CO 2 battery emerges as a transformative technology for simultaneous CO 2 utilization, high‐energy‐density storage, offering a dual solution to carbon neutrality, renewable energy integration. However, its practical deployment is hindered by high thermodynamic energy barriers, kinetic limitations associated with the conventional 4e − /3CO 2 pathway, which generates insulating Li 2 CO 3 discharge products, leading to severe overpotentials, parasitic reactions, and poor cyclability. This review comprehensively analyzes current polarization‐reducing tactics to mitigate these limitations through two complementary approaches: 1) enhancing reversibility of the 4e − /3CO 2 pathway through advanced catalyst design, electrolyte engineering, external field assistance, discharge product morphology control; 2) switching to the kinetically favorable 2e − /2CO 2 pathway by stabilizing Li 2 C 2 O 4 as the final discharge product via strategies including chemical bonding modulation, non‐covalent interactions, redox mediator‐, solvent‐mediated reaction pathway reconstruction, charge–discharge protocol optimization. By synthesizing pioneering studies, persistent challenges are identified, targeted research directions for advancing low‐polarization, long‐lifetime Li–CO 2 battery are proposed. This review is intended to help readers understand the pathway‐specific optimization mechanisms to drive innovation in the next‐generation carbon‐neutral energy storage.