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This study outlines an effective method for improving the electrochemical properties of MoO 3 by tuning the electronic spin state of Mo via Ni doping, which can enhance its reactivity and weaken the diffusion energy barrier between Zn2+ and MoO 3. [Display omitted] • The electron spin states of Mo are modulated via Ni-ion doping. • The storage mechanism of this electron spin states tuning strategy is clarified. • The assembled Ni-MoO 3 //Zn can afford a high capacity of 258 mAh g −1 at 1 A/g. Aqueous zinc-ion batteries (AZIBs) have received considerable potential for their affordability and high reliability. Among potential cathodes, α-MoO 3 stands out due to its layered structure aligned with the (0 1 0) 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-MoO 3 with Ni (Ni-MoO 3), tuning the electron spin states of Mo. Thus modification can activate the reactivity of Ni-MoO 3 towards Zn2+ storage and weaken the interaction between Ni-MoO 3 and intercalated Zn2+, thereby accelerating the Zn2+ transport and storage. Consequently, the electrochemical properties of Ni-MoO 3 significantly surpass those of pure MoO 3 , 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. [ABSTRACT FROM AUTHOR]