Rare Earth Pillars for Stabled Layered Birnessite Cathode Propelling Aqueous Zinc-Ion Batteries with Ultra-Long Cyclability

The weak structural stability, low intrinsic conductivity, and strong electrostatic interaction of cathode materials are still bottlenecks in aqueous zinc-ion batteries. Herein, a novel win-win strategy was proposed to fabricate the yttrium ions pre-intercalation birnessite-MnO2 cathode material. Benefiting from the unique advantages of rare earth ions with large radius, it could serve as interlayer pillars in the crystal lattice to stabilize the structure and enhance ionic conductivity. Furthermore, the high valence state of rare earth ions could significantly weaken the electrostatic interaction between zinc ions and host structures, thereby reducing charge transfer resistance and promoting ion transport. As a result, Y0.04K0.16Mn2O4·2.3H2O exhibits an ultra-long cycle stability of 24,000 cycles at a high current density of 8 A g-1, and the average capacity decay rate is only 0.002% per cycle. This work paves the way for the application of rare earth elements in energy storage.