Regulating the supercapacitor properties of hollow NiCo-LDHs via morphology engineering

Layered double hydroxides (LDHs) capture wide attention due to their unique properties. However, the easy agglomeration and limited exposure of surface active sites seriously limit the further improvement of their electrochemical performances. Herein, we report a strategy to improve the supercapacitor performance of hollow NiCo-LDHs by facile morphology engineering. By simply adopting multifunctional microbial derived carbon (M-FC) as an inducer, which can not only regulate the size of the outside nanosheets and the internal cavity, but also synergize with NiCo-LDHs via its excellent electrical conductivity and the supercapacitor feature. The optimal NiCo-LDHs/M-FC electrode material exhibits a high specific capacitance (1877 F g-1 at 1 A g-1) and excellent rate ability (up to 10 A g-1). The assembled asymmetric supercapacitor device using NiCo-LDHs/M-FC positive electrode and activated carbon negative electrode exhibits an energy density of 106.7 Wh kg-1 at the power density of 1333.8 W kg-1 at 2 mA cm-2, and still retained 80 Wh kg-1 at the power density of 9931 W kg-1 at 15 mA cm-2. This work demonstrates a facile strategy to regulate the microstructure and properties of LDHs.