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Relaxor ferroelectrics usually possess low remnant polarizations and slim hystereses, which can provide high saturated polarizations and superior energy conversion efficiencies, thus receiving increasing interest as energy storage materials with high discharge energy densities and fast discharge ability. In this study, a relaxor ferroelectric multilayer energy storage ceramic capacitor (MLESCC) based on 0.87BaTiO3‐0.13Bi(Zn2/3(Nb0.85Ta0.15)1/3)O3 (BT‐BZNT) with inexpensive Ag/Pd inner electrodes is prepared by the tape casting method. The MLESCC with two dielectric layers (layer thicknesses of 5 µm) sintered by a two‐step sintering method exhibits excellent energy storage properties with a record‐high discharge energy density of 10.12 J cm−3, a high energy efficiency of 89.4% achieved at an electric field of 104.7 MV m−1, a high temperature stability of the energy storage density (with minimal variation of <±5%), and energy efficiency (>90%) over a range of −75 to 150 °C at 40 MV m−1. These results suggest that the BT‐BZNT relaxor ferroelectric ceramic material can provide realistic solutions for high‐power energy storage capacitors.

Dielectric ceramic capacitors are fundamental energy storage components in advanced electronics and electric power systems owing to their high power density and ultrafast charge and discharge rate. However, simultaneously achieving...

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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.

Lead-free 0.985(0.96KNNT–0.04BNKZ)–0.015CZ ceramics were sintered at 1150–1190 °C.

A fast heating assisted two-step sintering method is developed to fabricate multilayer ceramic capacitors with ultrahigh energy-storage density and efficiency.

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