A novel 3D network single-phase Ni0.9Zn0.1O has been designed and synthesized by calcining a special metal-organic precursor (MOP) (MeO2C3H6, Me=Ni and Zn, the molar ratio of Ni: Zn=9:1) as the self-sacrificing template for the first time. Comparing with NiO or the mixture of NiO and ZnO, the new two-step Li-ion storage mechanism in the 3D network single−phase Ni0.9Zn0.1O has been discovered and verified to be: a reversible conversion reaction between Ni0.9Zn0.1O and Ni-Zn alloy (Ni0.9Zn0.1), and a reversible Li-alloying reaction between Ni-Zn alloy and Ni0.9Zn0.1Li. More remarkably, due to the new mechanism, the anode material shows a low initial discharge platform around ~ 0.5V (vs. Li+/Li). The first discharge voltage is lower than typical transition-metal oxides, which generally have higher initial discharge plateau around 1.0V (vs. Li+/Li). It is shown that the novel 3D network single-phase Ni0.9Zn0.1O has outstanding electrochemical performances, demonstrating discharge capacities (e. g. 1465.3 mAhg−1 at 100mAg−1 and 1055.6mAhg−1 at 800 mAg−1, respectively), excellent capacity retention and superior rate capability (e. g. capacity retention ratio of 92.9% after 150 cycles at 800 mAg−1 current density).