Enhanced High-Temperature Capacitive Energy Storage by 0.55Bi0.5Na0.5TiO3-0.45(Bi0.2Sr0.7)TiO3 Nanofibers in Polyetherimide Nanocomposites

Thelow discharge energy density and operation temperature of dielectricslimit the integration application of capacitors under extreme environmentconditions. In order to reduce the dielectric loss of Bi0.5Na0.5TiO3, 0.55Bi(0.5)Na(0.5)TiO(3)-0.45(Bi0.2Sr0.7)TiO3 (BNT-BST) nanofibers with optimized diameter were synthesized andutilized to improve the high-temperature capacitive energy storageof polyetherimide (PEI) nanocomposites. Benefiting from the introductionof nanofibers, the leakage current is significantly reduced and chargemigration is limited, contributing to the enhancement of the energystorage properties. For example, the leakage current density of the3 wt % BNT-BST/PEI nanocomposite is suppressed from 0.136 & mu;A/cm(2) of PEI to 0.056 & mu;A/cm(2) at 250 kV/mm. Thenanocomposite with 3 wt % BNT-BST achieves an excellent dischargeenergy density of 10.37 J/cm(3) at 560 kV/mm, which is 65.4%higher than that of PEI. When the environment temperature is up to100 & DEG;C, the discharge energy density of the nanocomposite maintainsa high level of 4.76 J/cm(3). Furthermore, the nanocompositedisplays outstanding cycling stability and fast charge-dischargeperformance. For instance, after 10(6) charge-dischargecycles at 150 kV/mm, the discharge energy density and efficiency remainat 99 and 95% of the initial values, respectively. This work providesa feasible idea for achieving high-energy density nanocomposites underhigh environment temperature.