Enhanced Energy Storage Properties for Bi(Ni0.5Hf0.5)O3 doped KNN Ceramics

In this work, (1- x )K 0.5 Na 0.5 NbO 3 - x Bi(Ni 0.5 Hf 0.5 )O 3 ( x = 0.15, 0.17, 0.2, 0.25) [abbreviated by (1- x ) KNN- x BNH] lead-free energy storage ceramics were prepared by the conventional solid-phase reaction method. The results indicate that BNH has been successfully incorporated into the KNN lattice, forming a homogeneous and stable solid solution. At the A site, hybridization between Bi 6p and O 2p orbitals can ameliorate the polarity, inducing an increase in P max . At the B site, Nb 5+ is substituted by (Ni 0.5 Hf 0.5 ) 3+ , leveraging differences in oxidation states and ionic radii to enhance the relaxation behavior. Moreover, the addition of BNH effectively refines grain size and optimizes breakdown field strength. At x = 0.17, the ceramics achieve optimal energy storage performance, with W tot = 1.375 J cm −3 , W rec = 1.071 J cm −3 , and η = 77.89%(∼184 kV cm −1 ).