Among zinc-ion battery (ZIB) cathodes, ZnMn₂O₄ (ZMO), with its high theoretical capacity and voltage, is an intriguing choice. In this study, we compared the electrochemical activity of a ZMO microrods cathode obtained through a simple co-precipitation process in the presence of a 0.1 M MnSO₄ (MS) solution as a full-time electrolyte, as an additive in zinc sulfate (ZMS) electrolyte (1 M ZnSO₄ + 0.1 M MnSO₄) and in its absence or a full-time zinc sulfate (ZS) electrolyte (1 M ZnSO₄), respectively. Systematic investigations including ex situ X-ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM) studies revealed the reasons for the superior stability and high reversibility of ZMO in the ZMS electrolyte medium. The exceptional performance was facilitated by the electrochemical equilibrium between Zn²⁺ and Mn²⁺ ions via a stable Zn²⁺ (de)insertion in the bulk, a reversible electro-deposition/dissolution of MnO_x from the Mn²⁺ additive in the electrolyte onto(from) the surface of the cathode and the reversible Zn-insertion into the formed surface MnO₂ layer. This finding is significant as it is contrary to the conventional understanding that the addition of Mn²⁺ merely tends to prevent manganese dissolution thereby facilitating a stable cycle-life performance of the cathode in ZIBs.

在锌离子电池（ZIB）阴极中，具有高理论容量和高电压的ZnMn ₂ O ₄（ZMO）是一个吸引人的选择。在这项研究中，我们比较了在存在0.1 M MnSO ₄（MS）溶液作为全时电解质，作为硫酸锌（ZMS）添加剂的情况下，通过简单的共沉淀过程获得的ZMO微棒阴极的电化学活性。）电解液（1 M ZnSO ₄ + 0.1 M MnSO ₄）和不存在的电解液或全日制硫酸锌（ZS）电解液（1 M ZnSO ₄）。系统的调查，包括现场调查X射线衍射（XRD），扫描电子显微镜（SEM）和透射电子显微镜（TEM）研究揭示了ZMO在ZMS电解质介质中具有出色的稳定性和高可逆性的原因。Zn ²⁺和Mn ²⁺离子之间的电化学平衡（通过在主体中形成稳定的Zn ²⁺（去）插入），MnO _x可逆地电沉积/从Mn ²⁺添加剂中溶解MnO _x促进了优异的性能。电解质从阴极表面到阴极表面，以及可逆的Zn插入到形成的表面MnO ₂层中。这一发现很重要，因为它与常规理解相反，即添加Mn ²⁺ 仅仅倾向于防止锰溶解，从而促进了在ZIBs中阴极的稳定循环寿命性能。