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

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. (c) 2020 Elsevier Inc. All rights reserved.

Automated summary

NiCoAl layered double hydroxide nanosheets were successfully synthesized using a one-step solvothermal method, showing optimized morphology and size for high-performance supercapacitor electrode materials. The nanosheets exhibited excellent electrochemical performance, with high specific capacitance and capacitance retention under different conditions, indicating their potential for future applications in energy storage devices.