Energy storage capacitors with high recoverable energy density and efficiency are greatly desired in pulse power system. In this study, the energy density and efficiency were enhanced in Mn-modified (Pb0.93Ba0.04La0.02)(Zr0.65Sn0.3Ti0.05)O-3 antiferroelectric ceramics via a conventional solid-state reaction process. The improvement was attributed to the change in the antiferroelectric-to-ferroelectric phase transition electric field (E-F) and the ferroelectric-to-antiferroelectric phase transition electric field (E-A) with a small Mn addition. Mn ions as acceptors, which gave rise to the structure variation, significantly influenced the microstructures, dielectric properties and energy storage performance of the antiferroelectric ceramics. A maximum recoverable energy density of 2.64 J/cm(3) with an efficiency of 73% was achieved when x = 0.005, which was 40% higher than that (1.84 J/cm(3), 68%) of the pure ceramic counterparts. The results demonstrate that the acceptor modification is an effective way to improve the energy storage density and efficiency of antiferroelectric ceramics by inducing a structure variation and the (Pb0.93Ba0.04La0.02)(Zr0.65Sn0.3Ti0.05)O-3-xMn(2)O(3) antiferroelectric ceramics are a promising energy storage material with high-power density.