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-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 Zn 2+ 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 Zn 2+ storage and weaken the interaction between Ni-MoO 3 and intercalated Zn 2+ , thereby accelerating the Zn 2+ 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.