Composition and strain engineered AgNbO-based multilayer capacitors for ultra-high energy storage capacity

• Published in: Journal of materials chemistry. A, Materials for energy and sustainability Vol. 9; no. 15; pp. 9655 - 9664
• Main Authors: Zhu, Li-Feng, Zhao, Lei, Yan, Yongke, Leng, Haoyang, Li, Xiaotian, Cheng, Li-Qian, Xiong, Xiangming, Priya, Shashank
• Format: Journal Article
• Published: 20.04.2021
• ISSN: 2050-7488; 2050-7496
• DOI: 10.1039/d1ta00973g

Antiferroelectric (AFE) materials owing to their double-loop-shaped electric-field ( E ) dependent polarization ( P ) are considered quite promising for energy-storage capacitors. Among the large family of AFE materials, the AgNbO 3 composition is attractive not only because it is environmentally friendly, but also because it has high recoverable energy storage density ( W rec ). However, the reported values of W rec < 4 J cm −3 in Ag(Nb 0.85 Ta 0.15 )O 3 multilayer capacitors are lower than that of the corresponding monolithic ceramic. This is attributed to high leakage current density ( J ) and inferior breakdown strength (BDS) in multilayer structures. Here we demonstrate that MnO 2 doping not only effectively reduces the J value and results in slim P - E loops, but also enhances the breakdown strength (BDS). Multilayer capacitors with composition Ag(Nb 0.85 Ta 0.15 )O 3 + 0.25 wt% MnO 2 (ANT + Mn) demonstrated an excellent W rec = 7.9 J cm −3 and efficiency η = 71%. Extensive investigations were conducted on ANT + Mn multilayer capacitors to demonstrate the role of strain engineering in enhancing the maximum polarization ( P max ) and Δ P values. Results reveal the effect of built-in stress in the active layers of multilayer capacitors on the magnitude of P max , remanent polarization ( P r ) and W rec , and provide guidance towards the development of high energy storage density in multilayer capacitors. With strain engineer and MnO 2 addition, an ultra-high energy-storage density W rec = 7.9 J cm −3 and efficiency η = 71% were achieved in Ag(Nb 0.85 Ta 0.15 )O 3 + 0.25 wt% MnO 2 multilayer capacitors.