Promoting cycle stability and rate performance of birnessite-type MnO2 cathode via cupper and bismuth dual ions pre-intercalation for aqueous zinc-ion batteries

Birnessite-type MnO2, as a promising and attractive cathode material for rechargeable aqueous zinc-ion batteries, is plagued by grievously poor cycling stability and rate performance, mainly attributed to structural collapse of MnO2 and slow Zn2+ diffusion kinetics. Herein, the Cu/Bi dual ions pre-intercalated birnessite-type MnO2 was fabricated by one-step hydrothermal method. It is validated by theoretical calculation in conjunction with experimentation that the Cu/Bi ions tends to occupy L1 sites, which not only can accelerate Zn2+ diffusion ki-netics owing to the low the Zn2+ diffusion energy barrier, but also can stabilize the structure of MnO2 host due to the formation of chemical bonds between the pre-intercalated Cu/Bi ions and oxygen atoms. Consequently, the CBMO cathode displays a high discharge capacity of 412.3 mAh/g at 0.1 A/g and distinguished cycling stability at 3 A/g after 1000 cycles with only approximately 0.0042 % capacity fading per cycle, which will be a strong competitive cathode material for developing stable and high-performance rechargeable aqueous zinc-ion batteries.