Gradient delocalized 4f-2p-3d orbital cascade of Gd-O-Mn sites remolding interfacial electronic landscape for accelerated Li-CO ₂ batteries redox kinetics

Abstract Conventional transition-metal cathodes constrained by a limited 3d-2p orbital manifold suffer from an unfavorable electronic structure that impedes the electrochemical kinetics of Li-CO2 batteries. Incorporating rare-earth 4f orbitals introduces strong spin-orbit coupling and a delocalized f-p-d cascade, fundamentally remolding interfacial electronic landscape. Herein, asymmetric Gd-O-Mn active sites are constructed via a 4f-2p-3d gradient orbital coupling strategy by doping gadolinium into Mn3O4 nanorods. This establishes a cascaded Gd 4f-O 2p-Mn 3d electronic conduit inducing directional charge redistribution and augmented electron density. The electropositive Gd dopant simultaneously elevates the O 2p band center and activates lattice oxygen redox chemistry, facilitating both the nucleophilic attack on CO2 and the subsequent cleavage of carbonate bonds. Consequently, the Gd-Mn3O4 cathode delivers an exceptional full discharge capacity of 14,640 mAh g-1, a remarkably low overpotential of 1.23 V, and extended cycling stability over 230 cycles. Comprehensive experimental and theoretical analyses reveal the f-p-d cascade coupling not only preserves the structural integrity of the MnO6 framework but also optimizes the adsorption energetics of key intermediates *C2O4. This work elucidates the mechanistic role of gradient orbital hybridization in stabilizing manganese-based cathodes and offers a new paradigm for the rational design of advanced catalytic sites in Li-CO2 batteries cathodes.