Facile synthesis of the SnTe/SnSe binary nanocomposite <i>via</i> a hydrothermal route for flexible solid-state supercapacitors

Abstract

Environmental degradation and energy shortage are the two biggest problems facing the world right now. Because of the limited supply of non-renewable sources, the production of environment-friendly energy and its storage has gained significant importance. Pseudocapacitors have lately caught the interest of energy specialists due to their greater energy/power density and prolonged cycle life. In this work, binding-free SnTe/SnSe (STSS) electrodes deposited onto Ni foam (NF) as the conductive substrate have been developed by a facile hydrothermal route for supercapacitor applications. Several analytical tools were utilized to study the morphological, structural and textural characteristics. The electrochemical results obtained from a three-electrode system suggest that the STSS electrode material exhibits great specific capacitance (<i>C</i> _s) of 1276 F g^-1, specific energy (<i>E</i> _d) of 46.45 W h kg^-1 and specific power (<i>P</i> _d) of 256 W kg^-1 @ 1 A g^-1. The results of <i>C</i> _dl indicate that the STSS (31.28 mF) has a larger <i>C</i> _dl value than those of SnTe (23.22 mF) and SnSe (26.35 mF). The analysis of electrochemical stability indicates that the STSS displays structural stability over 5000 cycles with a maximum capacitance retention of 96%. The Nyquist plot profile displayed a smaller <i>R</i> _ct value for STSS (0.89 Ω) than SnSe (1.13 Ω) and SnTe (1.97 Ω). The symmetric behavior of STSS was determined in 2.0 M potassium hydroxide. The results reveal that this material has a specific capacitance of 537.72 F g^-1 and specific energy of 78.32 W h kg^-1. These findings suggest that the STSS electrode might serve as a potential candidate for supercapacitors and other energy-saving equipment.