Synthesis and electrochemical properties of high entropy titanate powders (La_0.2X_0.2Ba_0.2Sr_0.2Y_0.2)TiO₃ (X = Na or K, Y = Ca or Pb) with perovskite structure

In this paper, four new high entropy titanate powders (La_0.2X_0.2Ba_0.2Sr_0.2Y_0.2)TiO₃ (X = Na or K, Y = Ca or Pb) were successfully synthesized by a sol‒gel strategy. When the pH value of the sol ranged from 3 to 4, it was easier to obtain pure high entropy powders with a perovskite structure. When the calcination temperature was in the range of 700 °C–900 °C, the high entropy powders were more beneficial to form a single solid solution with high XRD diffraction intensity and crystal quality. The as-synthesized powders with uniform distribution of A-position elements had a particle size between 50–120 nm and good dispersibility. The cyclic voltammetry (CV) and galvanostatic charge discharge (GCD) tests showed that these powders had better electrochemical properties and energy storage potential. When the discharge current was 1 A/g, the specific capacitance was higher than 136 F/g, even if the current density was 10 A/g, the specific capacity remained about 60 % of the initial.