Scalable Production of MnO₂/Carbon Composites via a Simple One-Step Precipitation Method for Aqueous Zn-Ion Batteries

Manganese dioxide (MnO2) is a promising cathode material for aqueous zinc-ion batteries (AZIBs) due to its considerable theoretical capacity, discharge voltage, high safety, and eco-friendliness. Here, a MnO2 composite with carbon materials was synthesized via a simple one-step precipitation method. The minor addition of carbon material significantly increases the yield of MnO2, which facilitates practical application in aqueous batteries. More importantly, during the precipitation process, the carbon material additive could regulate the growth morphologies of MnO2, contributing to increased specific surface area and alleviative Jahn–Teller distortion. Meanwhile, the incorporation of carbon materials improved the electrical conductivity, enhancing the electrochemical performance of the MnO2 composite. As a result, by employing the optimized cathode (MnO2@CNT), the full battery exhibits excellent specific capacity and maintains a stable cycling performance for over 1000 cycles at 3 C. Furthermore, its potential as a cathode material in sodium metal batteries is also demonstrated. This work provides a strategy for the practical utilization of MnO2 cathodes for AZIBs and contributes to realizing high-performance eco-friendly batteries.