화학공학소재연구정보센터
Electrochimica Acta, Vol.299, 298-311, 2019
Hetero-structured nanocomposites of Ni/co/O/S for high-performance pseudo-supercapacitors
Pseudo-supercapacitors are electrochemical energy storage/conversion devices that show promise in various commercial applications. However, poor electronic conductivity, inferior power output, and poor cycling stability hinder development. To improve pseudo-supercapacitor performances, novel heterostructured nanocomposites of Ni/Co/O/S materials are synthesized in this study using a hydrothermal electrochemical method consisting of hydrothermal deposition followed by hydrothermal electrochemical deposition at temperatures of 373 K, 383 K, 393 K and 403 K. Corresponding formation mechanisms of these hetero-structured platelet morphology materials are also proposed based on composition, morphology and electrochemical analysis. Among the prepared materials, excellent results were obtained in which the material prepared at 383 K (0.12 center dot Ni0.3Co2.7S2/0.064$ 4Ni(Co)(0.25x)(-OH)(2)center dot NiCo6.67-xOOH) provided optimal capacitance (996 F g(-1) (4.83 F cm(-2)) at 1 A g(-1)(5 mA cm(-2))), good rate capability (57.9% retention even with 10-fold increases in discharge current densities), and high cycle stability (No specific capacitance decay after 12000 cycles at 1.6 A g(-1) (8 mA cm(-2))). This material was also tested as the positive electrode of an asymmetric super-capacitive device with carbon as the negative electrode and provided outstanding energy densities (an energy density of 662 mWh . cm(-2) (34.1 Wh.kg(-1)) was achieved at a power density of 5654mWcm(-2) (282.7 Wkg(-1)) and an energy density of 330 mWh.cm(-2)(16.5Wh.kg(-1)) was maintained at a power density of 56534mWcm(-2) (2826.7 Wkg(-1))) and excellent stability (device maintained full capacitive retention after 16000 cycles at 0.67 A g(-1)(10 mA cm(-2))). (C) 2019 Elsevier Ltd. All rights reserved.