Li-Doping-Induced Structural and Electronic Structure Modulation in MgTiO ₃ for an Electrochemical Energy Storage Supercapacitor Device

High Resolution Image Download MS PowerPoint Slide Correlation among the crystal structure, electronic structure, and electrochemical energy storage mechanism has been investigated for Li-doped MgTiO 3 ceramics, prepared using the solid-state reaction method. Li doping leads to an increase in the occupied density of states in the band structure of MgTiO 3, leading to a diminishing of the t 2g /e g peak intensities in the O K-edge and Ti L-edge XANES spectra. Though Li doping did not change the Ti 4+ and Mg 2+ oxidation states, upon increasing Li content, the Mg 2 TiO 4 phase thrived. Under the three-electrode configuration, with KOH as the electrolyte, the MgTiO 3, 5Li-MgTiO 3, and 10Li-MgTiO 3 samples have shown surface-plus-diffusion-based energy storage and offered high specific capacitances of 81.0 F/g, 190.5 F/g, and 309.0 F/g, respectively (at a scan rate of 5 mV/s). A Swagelok cell, a two-electrode-based symmetric supercapacitor device, has been investigated, which delivered an energy density of 46 Wh/kg at a power density of 5000 W/kg at a current density of 2.5A/g, retained greater than ∼71% capacity after 10,000 cycles, and powered an LED, indicating excellent practical energy storage performance.

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