High-performing polysulfate dielectrics for electrostatic energy under harsh conditions

High-capacity polymer dielectrics that operate with high efficiencies under harsh electrification conditions are essential components for advanced electronics and power systems. It is, however, fundamen-tally challenging to design polymer dielectrics that can reliably withstand demanding temperatures and electric fields, which neces-sitate the balance of key electronic, electrical, and thermal parame-ters. Herein, we demonstrate that polysulfates, synthesized by sulfur(VI) fluoride exchange (SuFEx) catalysis, another near-perfect click chemistry reaction, serve as high-performing dielectric poly-mers that overcome such bottlenecks. Free-standing polysulfate thin films from convenient solution processes exhibit superior insu-lating properties and dielectric stability at elevated temperatures, which are further enhanced when ultrathin (-5 nm) oxide coatings are deposited by atomic layer deposition. The corresponding elec-trostatic film capacitors display high breakdown strength (>700 MV m-1) and discharged energy density of 8.64 J cm -3 at 150 degrees C, outper-forming state-of-the-art free-standing capacitor films based on com-mercial and synthetic dielectric polymers and nanocomposites.

Automated summary

Designing high-capacity polymer dielectrics that can operate efficiently under harsh electrical conditions is challenging. However, polysulfates synthesized through SuFEx catalysis were found to be high-performing dielectric polymers that can overcome these challenges. Free-standing polysulfate thin films exhibit superior insulating properties and dielectric stability at high temperatures, which can be further improved with ultrathin oxide coatings. These advancements lead to electrostatic film capacitors with high breakdown strength and discharged energy density, outperforming current state-of-the-art dielectric materials.