Synthesis, structural modification, and dielectric property enhancement of manganese and tin-doped bentonite composites for high-performance energy storage applications

This study explores the structural, morphological, optical, and dielectric properties of pure Bentonite (BT), Mn-doped Bentonite (Mn-BT), and Sn-doped Bentonite (Sn-BT) to evaluate their potential in advanced applications. X-ray diffraction (XRD) confirms the presence of Montmorillonite (M), Si, and Quartz (Q) phases, with slight peak shifts in Mn-BT and Sn-BT indicating successful incorporation of metal ions. Crystallite sizes increased from 16.07 nm for BT to 17.58 nm and 19.88 nm for Mn-BT and Sn-BT, respectively, suggesting structural modifications. Scanning electron microscopy (SEM) and Energy Dispersive X-ray (EDX) spectroscopy reveal a porous structure with homogeneously distributed elements, dominated by Si and Al, with minor quantities of Fe, Mg, Ca, and Na. UV-Vis analysis shows a reduction in bandgap energy from 4.14 eV for BT to 4.01 eV and 4.07 eV for Mn-BT and Sn-BT, respectively, indicating enhanced optical properties. Dielectric studies demonstrate significantly improved permittivity, with ε’ values higher in Mn-BT and Sn-BT compared to BT and reduced dielectric losses across a broad frequency range. Electrical conductivity increases with frequency, with hopping conduction dominating beyond a critical frequency. These results highlight the potential of Mn-BT and Sn-BT for applications in high-performance capacitors, energy storage devices, and environmental remediation.