Perspectives and challenges for lead-free energy-storage multilayer ceramic capacitors

TLDR

The growing demand for high‑power‑density electric and electronic systems has driven the development of multilayer ceramic capacitors (MLCCs) that offer low series resistance, high current handling, and high‑temperature stability, yet lead‑free variants still suffer from low energy density, limiting their widespread use. This review surveys perspectives and challenges for lead‑free energy‑storage MLCCs. The authors outline the energy‑storage mechanism and device characterization, review dielectric ceramic composition and structural optimization, discuss fabrication and electrode design, explore advanced pulsed‑power and high‑density converter applications, and highlight industrialization challenges and future prospects.

Abstract

Abstract The growing demand for high-power-density electric and electronic systems has encouraged the development of energy-storage capacitors with attributes such as high energy density, high capacitance density, high voltage and frequency, low weight, high-temperature operability, and environmental friendliness. Compared with their electrolytic and film counterparts, energy-storage multilayer ceramic capacitors (MLCCs) stand out for their extremely low equivalent series resistance and equivalent series inductance, high current handling capability, and high-temperature stability. These characteristics are important for applications including fast-switching third-generation wide-bandgap semiconductors in electric vehicles, 5G base stations, clean energy generation, and smart grids. There have been numerous reports on state-of-the-art MLCC energy-storage solutions. However, lead-free capacitors generally have a low-energy density, and high-energy density capacitors frequently contain lead, which is a key issue that hinders their broad application. In this review, we present perspectives and challenges for lead-free energy-storage MLCCs. Initially, the energy-storage mechanism and device characterization are introduced; then, dielectric ceramics for energy-storage applications with aspects of composition and structural optimization are summarized. Progress on state-of-the-art energy-storage MLCCs is discussed after elaboration of the fabrication process and structural design of the electrode. Emerging applications of energy-storage MLCCs are then discussed in terms of advanced pulsed power sources and high-density power converters from a theoretical and technological point of view. Finally, the challenges and future prospects for industrialization of lab-scale lead-free energy-storage MLCCs are discussed.