Understanding the enhancement of electrochemical properties of NiCo layered double hydroxides via functional pillared effect: An insight into dual charge storage mechanisms

• Published in: Electrochimica acta 2017-08, Vol.246, p.406-414
• Main Authors: Lin, Yinyin, Xie, Xiangli, Wang, Xin, Zhang, Bing, Li, Cunjun, Wang, Hai, Wang, Linjiang
• Format: Article
• Language: English
• Subjects: Anion exchange; Chemical synthesis; Electric properties; Electrochemical analysis; Electrodes; Hydroxides; Intercalation; Interlayers; Layered double hydroxide; Pillar effect; Studies; Supercapacitor; Supercapacitors; Surfactant
• ISSN: 0013-4686; 1873-3859
• DOI: 10.1016/j.electacta.2017.06.067

As-prepared NiCo layered double hydroxide nanosheets via the intrinsic pillar effect of sodium dodecylbenzene sulfonate (NiCo-SDBS-LDH), and found that the surface redox and intercalation behaviors take effect simultaneously in NiCo-SDBS-LDH via electrochemical analysis. [Display omitted] •An insight into dual charge storage mechanisms was proposed for NiCo-SDBS-LDH.•NiCo-SDBS-LDHs were prepared via the pillar effect of the SDBS.•Functional pillar leads to improved electrochemical properties of NiCo-SDBS-LDH.•Ion intercalation should be considered when designing LDH-based supercapacitors. In terms of the charge storage mechanism of supercapacitors, there are three types, including electrical double layer (EDL), surface redox reaction and intercalation reaction. The surface redox mechanism of transition metal-layered double hydroxides (TM-LDH) supercapacitor had been previously revealed. A dual charge storage mechanism integrated with surface redox and ion intercalation for LDH-based supercapacitors, however, is seldom reported before. For this purpose, here, we synthesized NiCo layered double hydroxide nanosheets via the intrinsic pillar effect of sodium dodecylbenzene sulfonate (NiCo-SDBS-LDH), and found that the surface redox and intercalation behaviors take effect simultaneously in NiCo-SDBS-LDH via electrochemical analysis. The NiCo-SDBS-LDH electrode having a relatively low specific surface area (15.28m2g−1) still exhibited a remarkable specific capacitance of 1094Fg−1 at a scan rate of 5Ag−1, and super long cycle life of 81% retention over 3000 cycles. A dual charge storage mechanism is subsequently proposed based on the analysis of our results to explain the excellent properties of NiCo-SDBS-LDH. We believe that the enhancements should mainly be ascribed to the structural feature of the SDBS stabilized NiCo-LDH and the expanded interlayer space of NiCo-SDBS-LDH. These findings open new doors to functional pillared effect to control the electrochemical behaviors of TM-LDH-based materials.