Tailoring NiCoAl layered double hydroxide nanosheets for assembly of high-performance asymmetric supercapacitors

• Published in: Journal of colloid and interface science Vol. 583; pp. 722 - 733
• Main Authors: Meng, Zhaohui, Yan, Wen, Zou, Mingye, Miao, Hao, Ma, Fangxing, Patil, Aniruddha B., Yu, Rui, Yang Liu, Xiang, Lin, Naibo
• Format: Journal Article
• Language: English
• Published: Elsevier Inc 01.02.2021
• Subjects: Asymmetric supercapacitors; Cycle stability; Nanoflower clusters; Rate performance; Solvothermal; Nanoflower clusters; Cycle stability; Rate performance; Solvothermal; Asymmetric supercapacitors
• ISSN: 0021-9797; 1095-7103
• DOI: 10.1016/j.jcis.2020.08.120

NiCoAl layered double hydroxide nanosheets. [Display omitted] •Layered double hydroxide nanosheets are prepared by a one-step solvothermal method.•The effects of solvothermal time and Co content on structure are investigated.•Al doping improves the electrical conductivity and activity of the electrode.•The assembled asymmetric supercapacitor exhibits excellent cycle performance. NiCoAl layered double hydroxide nanosheets (NiCoAl-LDHNs) were prepared by a one-step solvothermal method. The shape and size of the obtained nanosheets are optimized by adjusting the solvothermal time and the molar concentration ratio of Ni2+/Co2+ to obtain the electrode material with the best performance. When the solvothermal time is 9 h and the molar concentration ratio of Ni2+/Co2+ is 1:1, NiCoAl-LDHNs has the best morphology and electrochemical performance. When assembled into a supercapacitor, NiCoAl-LDHN-9 has a high specific capacitance of 1228.5 F g−1 at 1 A g−1. As the current density is increased to 20 A g−1, the specific capacitance is 1001.8 F g−1, which still has a high capacitance retention of 81.6%. When NiCoAl-LDHN-9 was assembled into an asymmetric supercapacitor, NiCoAl-LDHN-9//AC has a specific capacitance of 102.1 F g−1 at 0.5 A g−1. The asymmetric supercapacitor devices also show excellent electrochemical performance in terms of energy density (35.9 Wh kg−1 at 225.8 W kg−1), power density (4.8 kW kg−1 at 22.2 Wh kg−1) and cycle life (capacitance retention rate after 10,000 cycles is 87.1%). Those results indicate that NiCoAl-LDHN have the potential to be promising electrode materials for high performance supercapacitors.