Boosting the capacitive property of nickel cobalt aluminum layered double hydroxide in neutral electrolyte

• Published in: Journal of colloid and interface science 2020-10, Vol.578, p.96-105
• Main Authors: Deng, Lingjuan, Qin, Xiaowen, Qiao, Wenli, Gu, Yuanzi
• Format: Article
• Language: English
• Subjects: Capacitive property; Composite; LDH; Redox-active additives
• ISSN: 0021-9797; 1095-7103
• DOI: 10.1016/j.jcis.2020.05.027

[Display omitted] •RGO/Fe(CN)63--LDH composite has been prepared by ion-exchanged reaction.•RGO/Fe(CN)63--LDH supplies high capacitance in -1~0.8 V vs. SCE in Na2SO4 electrolyte.•The solid-state-supercapacitor based on RGO/Fe(CN)63--LDH works within 2.0 V.•Capacitive performance of LDH in natural electrolyte has been promoted. Layered double hydroxide (LDH) has shown great potential for energy storage due to their high theoretical specific capacitance, relatively low cost and eco-friendliness. LDH, however, always works in alkali aqueous electrolyte for supercapacitors, which brings serious environmental pollution. In this work, a reduced graphite oxide/Fe(CN)63−- nickel cobalt aluminum LDH (RGO/Fe(CN)63−-LDH) composite has been prepared via ion-exchange reaction using RGO/LDH as precursor. RGO/Fe(CN)63−-LDH electrode provides a specific capacitance of 221 F g−1 in a wide potential window of −1 ~ 0.8 V vs. SCE in Na2SO4 aqueous electrolyte, and which is much higher than that of LDH electrode (3.56 F g−1). Owing to the wide potential window of RGO/Fe(CN)63−-LDH electrode, a symmetrical solid supercapacitor device (RGO/Fe(CN)63−-LDH//RGO/Fe(CN)63−-LDH) with a high voltage of 2.0 V can deliver a high specific energy of 25.2 Wh kg−1 at a specific power of 250 W kg−1, and a capacitance retention of 75% after galvanostatic charging/discharging at 5 A g−1 for 5000 times. This work supplies enlightenment for boosting the capacitive performance of LDHs in neutral electrolyte.