Defect Engineering of BaTiO₃ Thin Films for High-Energy-Density Capacitor Applications

Abstract

Defect engineering in barium titanate thin films has become a central materials strategy for increasing the energy density, efficiency, and reliability of capacitors used in electrified transport, pulsed power, renewable energy conversion, and distributed grid infrastructure. This paper examines BaTiO₃ thin-film capacitors as socio-technical systems rather than isolated materials problems. It analyzes how oxygen vacancies, acceptor and donor doping, grain boundaries, interface states, strain, and nanodomain configurations influence permittivity, leakage current, breakdown strength, fatigue, and thermal stability. The discussion emphasizes structural trade-offs: strategies that increase permittivity often reduce breakdown strength or accelerate degradation, while defect passivation that improves reliability may lower effective polarization. Processing pathways, including chemical solution deposition, physical vapor deposition, atomic layer deposition, and aqueous tape casting for ultrathin multilayer ceramic capacitors, are compared in terms of defect control, scalability, and environmental burden. The paper then links materials architecture to manufacturing infrastructure, metrology, standards, supply-chain governance, critical raw materials, and policy. It argues that high-energy-density BaTiO₃ capacitors require coordinated innovation across defect chemistry, interface engineering, quality assurance, and responsible materials governance. Robust deployment depends not only on laboratory energy density but also on accelerated lifetime prediction, thermal management, recyclability, fair access to critical materials, and transparent standards. The conclusion identifies research priorities for balancing performance, reliability, sustainability, and equity in next-generation capacitor systems.