This study reports the synthesis and comprehensive characterization of Li3KP2O7 electro-ceramic pyrophosphate, prepared via the conventional solid-state reaction route. X-ray diffraction (XRD) confirmed the formation of a single-phase triclinic structure (space group \(\text{P}\stackrel{-}{1}\) ), while FTIR spectroscopy verified the presence of characteristic P₂O₇ functional groups, confirming the structural purity of the compound. Complex impedance spectroscopy, performed in the 1.5 Hz–10⁷ Hz frequency range and 453–613 K temperature range, revealed a negative temperature coefficient of resistance (NTCR) with an activation energy of 0.68 eV, confirming the semiconducting nature of Li₃KP₂O₇. The electrical response fitted well with an (Rg∥Cg∥Qg + Rgb∥Qgb) equivalent circuit, with grain resistance (Rg) and grain boundary resistance (Rgb), highlighting the predominant contribution of grain boundaries to the total impedance. AC conductivity followed Jonscher’s double power law, and the temperature dependence of the frequency exponents (s₁, s₂) suggested a transition between correlated barrier hopping (CBH) at high temperatures and non-overlapping small polaron tunneling (NSPT) at lower temperatures. The material exhibited a high dielectric constant (ε′ ≈ 1.3 × 106 at 1 kHz, 613 K) and low dielectric loss (tan δ ≈ 6), demonstrating excellent polarization stability and energy storage capability. UV–Vis optical absorption measurements indicated a direct band gap of 2.22 eV, further supporting its semiconducting behavior. These findings establish Li3KP2O7 as a promising multifunctional electro-ceramic with potential for solid-state devices, dielectric capacitors, and high-temperature energy storage applications.
