High Performance Capacitors Using BaTiO₃ Nanowires Engineered by Rigid Liquid-crystalline Polymers

Capacitors that provide high power density have attracted scientific and commercial interest, while often suffering from low energy density. Preparing a core-shell structured ceramic is regarded as a kind of effective method to improve the energy density, which is largely determined by the shell in the interfacial region. However, the current state-of-the-art of interfacial layer modification is predominantly based on utilizing flexible polymers, which are random polymer coils that collapse on the surface of any modified ceramic nanoparticles. Because of the characteristic properties of rigidity and orientation, the liquid-crystalline polymer poly{2,5-bis[(4-methoxyphenyl)oxycarbonyl]styrene} (PMPCS) is utilized to engineer the interfacial layer thickness on BaTiO₃ nanowire surfaces via surface-initiated reversible addition-fragmentation chain transfer polymerization (RAFT) method, in this paper. As a result, a high discharged energy density of 7.5 J/cm³ and an energy efficiency of 55.1% at 300 MV/m are achieved, respectively. The findings proved that rigid liquid-crystalline polymer is a promising modifier to prepare high performance capacitors and to explore the interfacial effect in dielectric nanocomposites.