Ceramic coating for electrostatic energy storage

With the ever-increasing environmental problems and shortage of fossil fuels, advanced energy storage technology for storing and converting renewable energies is highly desired. Compared with electrochemical devices, electrostatic capacitors possess much higher power densities, thus delivering ultrahigh charge–discharge rates, which are adequate for intermittent renewable energies. Polymer dielectrics are the functional materials in the electrostatic capacitors, which can store and discharge electrical energy via polarization and depolarization by applying or releasing electric fields. However, the existence of defect surface states fails to prevent charge injection from the electrode, which causes the degradation of insulating capabilities at elevated electric fields or temperatures. Nanocoatings based on ceramics pave a new way to revive the interfacial barrier effect of polymers to effectively suppress the charge injection. Significantly enhanced breakdown strength, charge–discharge efficiency, and energy density can be achieved in ceramic-coated polymers.