Excellent energy storage performance achieved in novel PbHfO3-based antiferroelectric ceramics via grain size engineering

•All ceramics were prepared by rolling process.•A very high Wrec of 12.2 J cm−3 and efficiency of 92% can be achieved in the Pb0.98La0.02(Hf0.65Sn0.35)0.995O3 ceramic.•The Pb0.98La0.02(Hf0.65Sn0.35)0.995O3 ceramic exhibits thermal stability over a wide temperature range.•The Pb0.98La0.02(Hf0.65Sn0.35)0.995O3 ceramic displays a high WD of 5.3 J cm−3 and a discharge speed of 103 ns.•The energy storage performance of AFEs can be improved by the approach of grain size engineering. Incremental attention has been paid to the PbHfO3-based antiferroelectric ceramics for its giant potential in dielectric capacitors and pulsed power techniques. Here, ultrahigh energy storage properties (Wrec = 12.2 J cm−3, η = 92%) and satisfied charge–discharge property (WD = 5.3 J cm−3, t0.9 = 103 ns, PD = 245 MW cm−3) are achieved in the Pb0.98La0.02 (Hf0.65Sn0.35)0.995O3 antiferroelectric ceramics. In addition, the studied ceramics also exhibited superior thermal stability within 20–120 °C (Wrec > 8 J cm−3, with minimal variation