Acid catalyst concentration effect on structure and ion relaxation studies of Li2O–P2O5–B2O3–SiO2 glasses synthesized by sol–gel process

Lithium phosphoborosilicate (LPBS) glasses were synthesized through the sol–gel process by varying nitric acid concentrations as a catalyst. The sol–gel process was monitored through XRD and DSC to optimize the LPBS glass forming treatment. Characterization of LPBS glasses was conducted using XRD, FTIR and DSC techniques. Impedance measurements were carried out at different temperatures on LPBS samples synthesized by sol–gel process with various nitric acid concentrations and impedance data were analyzed using Boukamp equivalent circuit software. The conductivity of LPBS samples was calculated from analyzed impedance data and it was found that sample synthesized with 2.5 N nitric acid concentration showed the high conductivity σ = 2.28(±0.02) × 10−7 S cm−1 at 443 K. Activation energy (Ea) is obtained from Arrhenius plots of dc conductivity and it is found to be 0.39 (±0.02) eV for the high conductance sample. Ac conductivity data were analyzed using Jonscher’s power law (JPL) and the power law exponent (s) exhibits a low s value for high conducting LPBS sample and a non-linear behavior with temperature. The electric modulus data were fitted with Kohlraush–William–Watts (KWW) stretched exponential function and modulus formalism is used to study the ionic relaxation behavior at different temperatures in LPBS glasses synthesized with varying nitric acid concentrations.