Surface engineering of layered SnO micro-plates for impressive high supercapacitor performance

Abstract

Tin monoxide is an important functional material, which is widely used in energy storage and optoelectronic devices. In this work, SnO micro-plates were synthesized by low-temperature hydrothermal method using aqueous ammonia as reducing agent. The thickness and surface morphology of the SnO micro-plates were delicately controlled by adjusting ammonia concentration. It is shown that surface modification has significant effect on their supercapacitor performance. Specifically, an ultra-high specific capacity of 1080 F•g−1 is obtained, which reaches ~75% of its theoretical faradaic capacitance value. Considering the typical thickness of ~250 nm, the electrons/ions can diffuse ~90 nm into the sample. In addition, the capacity remains an impressive value of 849 F•g−1 after 1000 cycles at current density of 1 A•g−1, suggesting excellent stability. Our studies show that the non-transition metal oxide, SnO, is a promising supercapacitor electrode material with high specific capacity and good cycle stability.