Taking advantage of synergistic effects, the ternary metal oxides have attracted tremendous interest. Herein, ZnMn₂O₄ nano-particles have been fabricated via a facile one-step approach at room temperature, that of simply mixing ZnO and MnO in KOH aqueous solution without templates. When used as an anode for lithium ion batteries, it delivers the excellent structure stability (1028.9 mA h g⁻¹ at 1.0 A g⁻¹ after 400 cycles). Surprisingly, the low-cost and eco-friendly route provides a novel strategy to synthesize the mixed transition metal oxide electrodes with readily scaled-up production.