<p>In this paper, ZnMn₂O₄/Mn₂O₃ nanoparticles were synthesized by an anhydrous sol–gel route to deal the poor capacity retention performance of Mn₂O₃ cathode material for Zn-ion batteries (ZIBs). The optimal Mn/Zn molar ratio in ZnMn₂O₄/Mn₂O₃ nanoparticles is 9:1. ZnMn₂O₄/Mn₂O₃ nanoparticles synthesized at the optimal Mn/Zn molar ratio (ZnMn₂O₄/Mn₂O₃-9) is composed of 28.98 at.% ZnMn₂O₄ nanoparticles and 71.02 at.% Mn₂O₃ nanopaticles. The nanoparticles have a size of 30–50&#xa0;nm. The gaps between the stacked nanoparticles lead to the porous structure of ZnMn₂O₄/Mn₂O₃-9. As a cathode material for ZIBs, ZnMn₂O₄/Mn₂O₃-9 delivers a high capacity of 356&#xa0;mAh g⁻¹ at a current density of 0.2&#xa0;A&#xa0;g⁻¹ after 600 cycles and maintains the high capacity during cycling. The high capacity and good capacity retention performance of ZnMn₂O₄/Mn₂O₃-9 is attributed to the anhydrous sol–gel route, the nanoscale and porous structure of the active material, and the introduction of ZnMn₂O₄ with smaller volume effect than Mn₂O₃.</p> Graphical abstract <p></p>