Exploring morphological variations in Ce-doped MnO2-based nanomaterials: rethinking the need for morphological control in achieving enhanced electrochemical storage

This study presents a cost-effective approach to developing MnO2-based, aiming to understand how modifications with Ce can affect the materials' morphology, properties, and application; thus, we comprehensively studied such properties. Interestingly, when just precursors for MnO2 were used, nanowires were obtained using a hydrothermal method. However, the subsequent doping with varying concentrations of Ce induced notable changes in the material morphology. Although the morphology changed, the surface areas and porous volumes increased with Ce content. X-ray diffraction analysis revealed the presence of the α-MnO2 tetragonal crystal phase in all materials, suggesting uniform Ce distribution and the absence of distinct crystalline phases. Such properties are vital for storage issues; thus, we decided to evaluate the physicochemical properties of the materials in supercapacitor evaluations. When submitted to electrochemical assessments, the materials presented pseudocapacitive behavior; also, tests for pseudosupercapacitors showed an increase in the specific capacitance with Ce-doping. Notably, these materials exhibited remarkable stability, increasing specific capacitance after 1000 charge–discharge cycles at high current rates. After choosing the optimum conditions of Ce-doping quantity, which did not show a tailored morphological control, an asymmetric supercapacitor was prepared; the device demonstrated a broad potential window, excellent rate performance, and the ability to maintain specific capacitance across various current densities. Remarkably, the asymmetric supercapacitor exhibited an energy density of 785.2 Wh kg−1 at a power density of 2880.02 W kg−1, marking a significant advancement in energy storage capabilities. Here, we have shown that the morphological control was not mandatory for the application of the materials. Furthermore, incorporating Ce into MnO2 enhanced supercapacitor performance, suggesting chemical composition is as vital as morphology in high-performance energy storage.