Boosting the Zn2+ storage capacity of MoO3 nanoribbons by modulating the electrons spin states of Mo via Ni doping

Aqueous zinc-ion batteries (AZIBs) have received considerable potential for their affordability and high reliability. Among potential cathodes, α-MoO₃ stands out due to its layered structure aligned with the (010) plane, offering extensive ionic insertion channels for enhanced charge storage. However, its limited electrochemical activity and poor Zn²⁺ transport kinetics present significant challenges for its deployment in energy storage devices. To overcome these limitations, we introduce a new strategy by doping α-MoO₃ with Ni (Ni-MoO₃), tuning the electron spin states of Mo. Thus modification can activate the reactivity of Ni-MoO₃ towards Zn²⁺ storage and weaken the interaction between Ni-MoO₃ and intercalated Zn²⁺, thereby accelerating the Zn²⁺ transport and storage. Consequently, the electrochemical properties of Ni-MoO₃ significantly surpass those of pure MoO₃, demonstrating a specific capacity of 258 mAh g^-1 at 1 A g^-1 and outstanding rate performance (120 mAh g^-1 at 10 A g^-1). After 1000 cycles at 8 A g^-1, it retains 76 % of the initial capacity, with an energy density of 154.4 Wh kg^-1 and a power density of 11.2 kW kg^-1. This work proves that the modulation of electron spin states in cathode materials via metal ion doping can effectively boost their capacity and cycling durability.