Synthesis of cobalt silicate nanosheets with mesoporous structure and high surface area as the promising electrode for high-performing hybrid supercapacitor

Abstract

The construction of electrode materials with novel morphology and structure showing enhanced electrochemical properties have received great attention and always been a task full of challenges and opportunities. Herein, mesoporous cobalt silicate nanosheets (Co2SiO4 NSs) with excellent electrochemical properties are firstly synthesized by the sacrificial template stÖber SiO2 spheres. Thanks to the small diameter and high specific surface area (114 m2 g−1), Co2SiO4 NSs can supply abundant reactive sites where the electrochemical reaction occurs, therefore they can accelerate kinetic process for mass transfer and achieve satisfactory electrochemical performance. The Co2SiO4 NSs show the specific capacitance of 638 F g−1 (319 C g−1) at the current density of 0.5 A g−1, and the capacitance stability after 10000 cycles is 82 % of the initial value. The Co2SiO4//AC hybrid supercapacitor (Co2SiO4//AC HSC) comprising of Co2SiO4-3 NSs and activated carbon (AC) achieves the specific capacitance of 571 mF cm−2 (799 mC cm−2, 81 F g−1) at 1 mA cm−2, the capacitance retention of 92 % after 10000 cycles and the energy density of 1.55 Wh m−2 at the power density of 1.75 W m−2. The device also can light the light emitting diode (LED) bulb in the practical application field. This work firstly presents the in-situ growth of mesoporous Co2SiO4 NSs by sacrificial template stÖber SiO2 spheres with noteworthy electrochemical property for high-performing HSC, which can be popularized to synthesize other transition metal silicates (TMSs) with improved electrochemical properties.