Display omitted •Electrochemical reversibility of MANiCl3 enhances the capacity retention of electrode.•Extraction of MA+ occurs creating vacancies and increasing lithium concentration.•Li + atoms occupy both the interstitial space and the MA vacancies in the structure.•MANiCl3 displays anodic behavior and remarkable initial capacity of discharge. At present, efforts are being made to find new low-cost materials for photovoltaic, optoelectronic and energy storage applications. In this regard, compounds of the halide perovskite type have been increasingly studied over the past few years. The incorporation of small cations in these compounds and their possible use in rechargeable batteries can be achieved by the electrochemical reversibility technique, where perovskites with large cations are used to obtain a new isostructural compound with smaller cations and large interstitial space or free vacancies for ionic transport. The present work studied the electrochemical reversibility of lithium-ion into CH3NH3NiCl3 (MANiCl3) active material, after the formation of MA+ vacancies or interstitial spaces, taking both experimental and theoretical approaches. The material displayed an anodic behavior and an initial capacity of discharge of ca. 170 mAhg−1 at 0.2C (0.1 mA), a full capacity retention up to the first 25 cycles of charge–discharge, and even reached a retention of up to 80 % of initial capacity at the 80th cycle. First-principles density functional theory calculations show that the shape of the crystal lattice and volume changes of all the different phases involved in the electrochemical process are tiny, at about 3 Å3 per cell. In addition, there are no appreciable elastic contributions to the energy variation during the de-lithiation/lithiation process, indicating that memory effects are not an issue. The calculated formation energies of the lithiated structures and the open circuit voltages are −2.91 eV and 1.33 V for LinMA1-nNiCl3 and −1.41 eV and 2.91 V for Li2nMA1-nNiCl3, respectively. These findings suggest that incorporating one or, at most, to two lithium atoms is favorable for the overall stability and electrochemical performance.