In a paper to be published in the forthcoming issue of NANO, a team of researchers from the China University of Mining and Technology have fabricated an asymmetric supercapacitor (ASC) based on FeCo-selenide nanosheet arrays as positive electrode and Fe 2 O 3 nanorod arrays as negative electrode. There is evidence that FeCo-selenide could be the next-generation promising electrode materials in energy storage devices.

Supercapacitors have been considered as the most attractive candidate for energy storage devices and are widely used in the field of portable electronic equipment and electric car due to their high power density, fast charge/discharge rate, low maintenance cost and long cycling life. Similar to the transition metal bimetallic oxide and sulfides, metal selenides can be considered as a promising candidate for electrode materials because of Selenium belonging to the same group element as Sulfur.

A team of researchers from the China University of Mining and Technology successfully fabricated a solid-state energy storage device based on FeCo-selenide as positive electrode and Fe 2 O 3 as negative electrode. Their report appears in the forthcoming issue of the journal NANO.

The FeCo-selenide was synthesized using a two-step hydrothermal process, with Ni foam as substrate and current collector. The as-prepared FeCo-selenide nanosheet arrays on Ni foam shows specific capacitance of 978 F/g (specific capacity of 163 mAh/g) obtained at current density of 1 A/g and cycle stability of 81.2% was achieved after 5000 cycles. And the ASC device operating at 1.6 V delivers a maximum energy density of 34.6 W h/kg at power density of 759.6 W/kg, which is higher than that of many other ASC reported previously. The practical application of the ASC deviced was explored by assembling several capacitors into a series circuit to light 1 LED bulb and light board of "CUMT". The ASC device exhibited excellent electrochemical performance which provides the evidence that FeCo-selenide could be the next-generation promising electrode material in energy storage devices.

The team at China University of Mining and Technology is currently exploring options to better control the high voltage output and create high-performance ASC. For optimal electrochemical performance and decrease in cost, the team would also like to explore a device based on selenide composites in its application.

###

Additional co-authors of the paper are Jiqiu Qi, Yanwei Sui, Fei Yang, Fuxiang Wei, Yezeng He, Qingkun Meng and Zhi Sun.

This research was supported by the Fundamental Research Funds for the Central Universities.

Corresponding author for this study in NANO is Yanwei Sui, wyds123456@outlook.com.

For more insight into the research described, readers are invited to access the paper on NANO.