HIPES: Lead-free ferroelectrics for high power energy storage in dielectrics

The energy crisis and environmental issues caused by the burning of fossil fuels are major challenges facing mankind. In recent years, energy storage materials have attracted increasing scientific and industrial attention, coupled with the development of green and renewable energy sources. Renewable energies must be transformed into electrical energy for practical uses. In this form, the energy is safe, clean, well-suited to long-distance transportation, and can easily be transformed into other types of energy. Various technologies have been used to store energy from renewable sources. Dielectrics play an important role in high-power energy storage applications, such as electromagnetic devices and hybrid electric vehicles, due to their fast charge-discharge capability (typically in the nanosecond range). However, the energy storage density of commercial dielectric capacitors is very low compared to batteries which have low power density. The energy density of dielectric capacitors is closely related to the electric field-induced transitions in the ferroelectrics. To date, the best ferroelectric materials are based on lead-containing oxides. However, toxicity and environmental concerns have prompted the search for lead-free alternatives. High-entropy materials represent a promising class of disordered multicomponent materials with tailorable properties and potentially unprecedented performances, including excellent dielectric properties. Here, considering the high entropy effect on structures and electrical properties of ferroelectrics, the compositions are designed according to the high entropy concept, and the strategies to improve the energy density in environmentally-friendly lead-free ferroelectrics are proposed to enable the development of these materials for high-power energy storage capacitors.