The design and fabrication of biomass-based energy storage devices is becoming a new trend to reduce the depletion of non-renewable resources. Herein, b-Ni(OH) 2 nanosheet arrays grown on willow catkins-derived hollow carbon microtubes is prepared for the first time through a facile acid treatment and subsequent hydrothermal process. In the b-Ni(OH) 2 @acidtreated carbon microtube [b-Ni(OH) 2 @ACMT] composite, b-Ni(OH) 2 nanosheet arrays can be controllably grown on both internal and external surfaces of carbon microtubes, realizing effective utilization of the hollow tubular structure. In addition, carbon microtubes are not only employed as an effective support for the dispersion of b-Ni(OH) 2 nanosheets, but also served as a long-range conductive micro-current collector for electron transfer. Furthermore, the hollow tubular structure accompanied by the capillary effect provides fast channels for ion diffusion. As a consequence of this unique hierarchical structure, the electrode based on the b-Ni(OH) 2 @ACMT composite exhibits a high specific capacitance of 1568 F g À1 at 1 A g À1 , remarkable capacitance retention of 51.0 % even at 20 A g À1 , and excellent cycling stability of 84.3 % retention after 3000 cycles. An asymmetric supercapacitor, with b-Ni(O-H) 2 @ACMT composites as the positive electrode and porous carbon microtubes as the negative electrode, achieves a high energy density of 37.8 W h kg À1 at 750 W kg À1 , indicating its potential application in energy storage devices.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.