Cu superstructures fabricated using tree leaves and Cu–MnO2 superstructures for high performance supercapacitors

Abstract
Copper (Cu) superstructures have been originally synthesized by using natural sapless leaves. A novel hybrid nanoarchitecture, Cu–MnO2 composite, is prepared through facile coating of a thin MnO2 nanofilm onto the highly electronically conductive Cu superstructures. Benefiting from their unique structures, as electrode materials of supercapacitors the composite superstructures have a high specific capacity of 1024 F g−1 at 1.5 A g−1 and good capacity retention of around 96% after 2000 electrochemical cycles.