Na-Ion Battery with 180 Wh/kg and Long Cycle Life

High Resolution Image Download MS PowerPoint Slide Na-ion batteries are promising energy storage technologies, yet cathodes suffer from structural instability during deep cycling, leading to a trade-off between energy density and long-term life. Here, we introduce a “local electron density engineering” strategy to address this intrinsic challenge. We propose that structural degradation originates from the withdrawal of electron density from lattice oxygen by a high-valence transition metal. By incorporating stable d 10 (Zn 2+ ) and d 0 (Ti 4+ ) ions, we create an electron-rich oxygen framework that acts as an “electron buffer”, resisting this electron depletion. Reinforced further by Ca 2+ pillars in the Na + layers, our single-crystalline Na 0.96 Ca 0.02 Cu 0.038 Zn 0.053 Ni 0.409 Mn 0.315 Ti 0.185 O 2 cathode exhibits a low volume change of ∼4% under deep desodiation. In 26700 cylindrical full cells, it delivers an energy density of 181.2 Wh kg –1 and retains ∼80% capacity rentention after 1000 cycles. These results establish a new design pathway for developing ultrastable, high-energy cathode materials for next-generation Na-ion batteries.