Itinerant-electron dynamics suppressing Jahn-Teller distortions: Enabling high-rate and stable sodium-ion storage

Jahn-Teller distortion (JTD) remains a fundamental bottleneck for transition metal oxides (TMOs) in electrochemical energy storage, where the e g -orbital single-electron occupancy induces irreversible octahedral collapse and rapid capacity fading. Here, we pioneer an itinerant-electron-mediated dynamic suppression strategy that fundamentally reshapes the JTD evolution pathway through π - d orbital hybridization engineering. By constructing reduced graphene oxide/TMO heterointerfaces (rGO/MO x , M = Fe/Ni/Mn), localized 3 d electrons are transformed into delocalized itinerant states, which (1) eliminate e g -band degeneracy via orbital repopulation and (2) establish an electron density buffer layer to neutralize lattice strain. This electronic regulation enables ultrafast Na + diffusion kinetics (508.3 F g −1 at 1 A g −1 → 304.6 F g −1 at 20 A g −1 ) and near-zero lattice deformation (91.07% capacitance retention after 20,000 cycles). Synchrotron-based X-ray absorption spectroscopy and density functional theory calculations reveal that itinerant electron dynamics actively decouple the Mn 3+ d 4 electronic configuration from JTD triggering, leading to a dramatic suppression of octahedral distortion compared to the conventional MnO 2 . The proposed electron delocalization-to-lattice stabilization paradigm opens a universal route to design distortion-resistant electrodes for high-power energy storage systems.