<p>Sol–gel auto combustion was used to create polycrystalline ZnMn_2-xLa_xO₄ nanoparticles, where <i>x</i> = 0.0, 0.05, 0.1, and 0.15 zinc manganite. La concentration, structural, electrical conductivity, magnetic, and electrochemical properties were found to be strongly correlated. ZnMn₂O₄ and other manganese-rich spinels have a tetragonal spinel structure due to the octahedral MnO₆ unit’s Jahn–Teller distortion. ZnMn_2-xLa_xO₄ oxides progressively change to a cubic spinel structure as more La occurs in the place of manganese. Expanding La substitution causes the lattice parameter <i>c</i> to drop from 9.2178 to 9.2158 A° and the lattice parameter <i>a</i> = <i>b</i> to rise from 5.6869 to 5.9107 A°. For rare-earth dopants such as lanthanum, substitution doping is necessary due to their (La) large ionic radii in comparison to manganese and zinc. Smaller particles would form as a result of doping materials like La form Zn and Mn, which would change particle mobility. Differences between zinc manganite and zinc manganite doped with La may be due to lattice strain and structural disorder. The conductivity value from both pure and (0.15%) doped samples rises from 16.46 × 10⁻⁴ S cm⁻¹ to 323.89 × 10⁻⁴ S cm⁻¹ with increasing La substitution. The enhanced electrochemical performance is caused by the formation of a La doped ZnMn₂O₄ which can suppress the volume expansion during the charge–discharge process.</p>