In this study, paraelectric ceramics, (Ba0.85Ca0.15)(Zr0.10Ti0.90)(1- x)(Ni1/3Nb2/3)(x)O-3, abbreviated as BCZT-xNN (with x = 0.1, 0.2, 0.3, 0.4) were prepared via a solid-state reaction method. By introducing a B-site complexion, (Ni1/3Nb2/3)(4+), the Curie temperature of the ceramic could be reduced to below room temperature. The effects of this B-site (Ni1/3Nb2/3)(4+) complex-ion substitution on the phase structure, surface microstructure as well as the dielectric, ferroelectric, and energy storage properties of the ceramic were systematically investigated. After adding NN, BCZT-xNN shows a single phase perovskite structure without evidence of a second phase. In addition, we observed high stability with respect to both temperature (-55 to 160 degrees C) and frequency (10(2)-10(7) Hz). Doping with NN produces slim polarization-electric field hysteresis loops and enhanced energy storage properties, while the efficiency decreases. When x = 0.3, the highest energy storage density reached 0.66 J/cm(3) for a high electric field (20 kV/mm), and the respective energy efficiency was 88.1%. These properties indicate that the environmental friendly BCZT-xNN ceramics are promising candidates for commercial energy storage devices.