Quantum Size Effect to Induce Colossal High‐Temperature Energy Storage Density and Efficiency in Polymer/Inorganic Cluster Composites

• Published in: Advanced materials (Weinheim) 2023-07, Vol.35 (30), p.e2301936-n/a
• Main Authors: Yang, Mingcong, Wang, Shaojie, Fu, Jing, Zhu, Yujie, Liang, Jiajie, Cheng, Sang, Hu, Shixun, Hu, Jun, He, Jinliang, Li, Qi
• Format: Article
• Language: English
• Subjects: Chemical synthesis; Clusters; dielectric capacitors; Dielectrics; Discharge; Efficiency; Electric fields; Energy storage; High temperature; high‐temperature energy storage; Materials science; Metal oxides; Nanocomposites; Nanoparticles; Polymer blends; polymer composites; Polymers; quantum size effect; Size effects; Surface defects; Temperature
• ISSN: 0935-9648; 1521-4095
• DOI: 10.1002/adma.202301936

Polymer dielectrics need to operate at high temperatures to meet the demand of electrostatic energy storage in modern electronic and electrical systems. The polymer nanocomposite approach, an extensively proved strategy for performance improvement, encounters a bottleneck of reduced energy density and poor discharge efficiency beyond 150 °C. In this work, a polymer/metal oxide cluster composite prepared based on the “site isolation” strategy is reported. Capitalizing on the quantum size effect, the bandgap and surface defect states of the ultrasmall inorganic clusters (2.2 nm diameter) are modulated to markedly differ from regular‐sized nanoparticles. Experimental results in conjunction with computational simulation demonstrate that the presence of ultrasmall inorganic clusters can introduce more abundant, deeper traps in the composite dielectric with respect to conventional polymer/nanoparticle blends. Unprecedented high‐temperature capacitive performance, including colossal energy density (6.8 J cm−3), ultrahigh discharge efficiency (95%) and superior stability at different electric field frequencies, are achieved in these polymer/cluster composites up to 200 °C. Along with the advantages in material preparation (inexpensive precursors and one‐pot synthesis), such polymer/inorganic cluster composite approach is promising for high‐temperature dielectric energy storage in practical power apparatus and electronic devices. The quantum size effect is utilized to modulate the band structure of aluminum oxide clusters. Based on the “site isolation” strategy, a polymer/aluminum oxide cluster composite with uniform dispersion of the inorganic phase is prepared with one‐pot synthesis, which exhibits a colossal storage energy density of 6.8 J cm−3 and ultrahigh efficiency over 95% at 200 °C.