Designing electrodes in a highly ordered structure simultaneously with appropriate orientation, outstanding mechanical robustness, and high electrical conductivity to achieve excellent electrochemical performance remains a daunting challenge. Inspired by the phenomenon in nature that leaves significantly increase exposed tree surface area to absorb carbon dioxide (like ions) from the environments (like electrolyte) for photosynthesis, we report a design of micro-conduits in a bioinspired leaves-on-branchlet structure consisting of carbon nanotube arrays serving as branchlets and graphene petals as leaves for such electrodes. The hierarchical all-carbon micro-conduit electrodes with hollow channels exhibit high areal capacitance of 2.35 F cm−2 (~500 F g−1 based on active material mass), high rate capability and outstanding cyclic stability (capacitance retention of ~95% over 10,000 cycles). Furthermore, Nernst–Planck–Poisson calculations elucidate the underlying mechanism of charge transfer and storage governed by sharp graphene petal edges, and thus provides insights into their outstanding electrochemical performance.

Abstract

Based on analyzing the problem of the screen with circular, linear, and elliptical trajectory, the spatial Lissajous trajectory has been put forward. The article analyzes the dynamic theory of the spatial Lissajous trajectory screen, and the virtual simulation with discrete-element method is applied to study the solid migration rules. A discrete-element model is developed based on the JKR contact model which takes into considerations viscous forces of contacting particles. Two important factors, migration velocity and filter ratio, are selected to describe the working performance of the vibrating screen. The research results show that the spatial Lissajous vibrating screen has approximate solid migration velocity like the linear vibrating screen, but the filter rate of spatial Lissajous trajectory is the highest. Therefore, the spatial Lissajous trajectory vibrating screen can reduce the phenomenon of screening blockage, and the advantage will be more evident in the case of high drilling fluid viscosity, high mesh number, and serious screen blockage.