Significant enhancement of energy storage properties of BaTiO₃-based ceramics by hybrid-doping

In the present study, we designed a new system, Ba(Ti_0.99-1.25xMn_0.01Nb_x)O₃ (x = 0.5%, 1.0%, 1.25%, 1.5%), to improve the energy storage properties of BaTiO₃–based ceramics. Here the acceptor dopant Mn was introduced to enhance the maximum polarization P_max while reducing the remnant polarization P_r by inducing aging phenomena. The donor dopant Nb was added to make the hysteresis loop slimmer and slender through ‘softening’ effect. And the ratio of acceptor and donor was adjusted to modify the energy storage properties by modulating the shape of hysteresis loop. Results showed that an enhancement of 76% over pure BaTiO₃ in recoverable energy storage density (W_rec) has been achieved in hybrid-doped samples, accompanied by a high energy conversion efficiency (η) up to 86%. Hereinto, donor-dominant samples doped with 1% Mn and 1.25% Nb exhibited the highest W_rec and η with excellent thermal stability. This study proved the feasibility of enhancing the energy storage properties by hybrid doping and may provide a new viewpoint for later studies.