In-situ construction of MnCO₃@CNTs nanosheets for high-capacity aqueous zinc ion batteries

Owing to severe agglomeration of manganese carbonate (MnCO₃) during its synthesis, it exhibits rapid decay cycle performance when used as a cathode material in aqueous zinc ion batteries. To overcome this drawback, we synthesized a MnCO₃ material with carbon nanotubes (CNTs) (i.e., MnCO₃@CNTs) via a one-step solvothermal method using a hybrid modification strategy. MnCO₃ nanospheres were grown in-situ on a two-dimensional (2D) plane that was orderly interwoven by tubular single fibers of carbon to form a leaf-like nanosheet structure. The surface area of the MnCO₃@CNTs material was enlarged enormously through the special nanosheet structure, and its stability was improved by the supporting structure of the CNTs. As a result, the MnCO₃@CNTs exhibited a discharge capacity of 247.6 mAhg⁻¹ at a current density of 0.1 A g⁻¹. The energy storage mechanism of MnCO₃@CNTs was further explored using a series of electrochemical kinetic analyses and ex-situ characterization tests. This modification method not only broadens the application field of MnCO₃, but also provides the possibility of modifying more cathode materials.