Metal–Organic Framework-Derived MnO/C Nanocomposite with Lamellar Porous Structure for High-Performance Aqueous Zinc-Ion Battery

Manganese oxide (MnO) is a promising cathode for aqueous zinc-ion batteries; however, issues such as low electrical conductivity, Mn²⁺ dissolution, and sluggish kinetics lead to poor electrochemical performance that block its commercialized application. Herein, the first utilization of Mn-based metal–organic frameworks synthesized from manganese salt and 1,2,4,5-benzenetetracarboxylic acid to fabricate MnO/C composite materials is presented. The analysis of electrochemical testing demonstrates that carbon-coated MnO can effectively promote electrochemical properties compared to the pure MnO. Additionally, the Zn²⁺/Mn²⁺ concentration is optimized in order to maximize the electrode's potential in terms of electrochemical performance. The MnO/C-600 electrode delivers a higher specific capacity of 322 mAh g⁻¹ at 0.1 A g⁻¹ and exhibits a capacity of 270 mAh g⁻¹ after 360 cycles at 0.5 A g⁻¹ in the 2.0 m ZnSO₄ + 0.2 m MnSO₄ system. The results also indicate that the MnO/C-600 electrode has higher diffusion coefficients, and its unique structure improves structural stability and ion/electron transfer. Furthermore, the energy storage mechanism of the MnO/C-600 electrode is investigated. Herein, a method is provided for preparing an inexpensive and convenient MnO/C cathode for high-performance aqueous zinc-ion batteries.