Facile synthesis of amorphous aluminum vanadate hierarchical microspheres for supercapacitors

Abstract

Micro-nanostructured mixed metal vanadates have recently garnered enormous attention owing to their remarkable performances in catalysis, energy storage and conversion. In this work, we report the synthesis of amorphous aluminum vanadate hierarchical microspheres via a simple hydrothermal approach with polyvinylpyrrolidone as a surface directing agent. Amorphous aluminum vanadate hierarchical microspheres are firstly described as a kind of electrode material for supercapacitors. The measured specific capacitance of the amorphous aluminum vanadate electrode is 497 F g⁻¹ at 1 A g⁻¹ with good stability and a retention capacity of 89% after 10 000 cycles. In addition, the fabricated asymmetric supercapacitor device delivered better performance with an extended operating voltage window of 1.5 V, excellent cycle stability (10 000 cycles, 85% capacitance retention), high energy density (37.2 W h kg⁻¹ at 1124.4 W kg⁻¹) and high power density (11 250 W kg⁻¹ at 25 W h kg⁻¹). This study essentially offers a new kind of vanadate as an electrochemical active material for the development of supercapacitors.