Hybrid supercapacitor with nano-TiP₂O₇ as intercalation electrode

Nano-size (≤100 nm) TiP₂O₇ is prepared by the urea assisted combustion synthesis, at 450 and 900 °C. The compound is characterized by powder X-ray diffraction, Rietveld refinement, high resolution transmission electron microscopy and surface area methods. Lithium cycling properties by way of galvanostatic cycling and cyclic voltammetry (CV) showed a reversible and stable capacity of 60 (±3) mAh g^-1 (0.5 mole of Li) up to 100 cycles, when cycled at 15 mA g^-1 between 2-3.4 V vs. Li. Non-aqueous hybrid supercapacitor, TiP₂O₇ (as anode) and activated carbon (AC) (as cathode) has been studied by galvanostatic cycling and CV in the range, 0-3 V at 31 mA g^-1 and exhibited a specific discharge capacitance of 29 (±1) F g^-1stable in the range, 100-500 cycles. The Ragone plot shows a deliverable maximum of 13 Wh kg ^-1 and 371 W kg^-1 energy and power density, respectively.