In this work, monodispersed and high quality crystalline MnCO₃ micro-peanuts and MnCO₃ nano-shuttles were prepared by a simple hydrothermal method. A growth mechanism was proposed to elucidate the influence of reactant components on the morphology and size of the prepared MnCO₃ samples. Both structures were employed as active electrode materials in lithium ion batteries. The electrochemical performance of the obtained MnCO₃ samples was examined by analyzing the cyclic voltammograms, galvanostatic charge–discharge, rate performance and electrochemical impedance. At a current rate of 250 mA h g⁻¹, the reversible capacity of the MnCO₃ nano-shuttle electrode after 500 cycles was 605 mA h g⁻¹, while that of the MnCO₃ micro-peanut electrode was 463.4 mA h g⁻¹. The results indicated that the MnCO₃ samples synthesized by this method presented wonderful electrochemical properties, which could be used as promising active materials in lithium ion batteries.