Facile Method of Preparation of Graphene Nanoscrolls for High-Performance Lithium-Ion Capacitors

The configuration of the battery-type anode and the capacitor-type cathode has been demonstrated to facilitate the achievement of elevated power and energy densities in lithium-ion capacitors (LICs). The mismatch between electrode reaction kinetics and capacity pose limits the development of LICs. And the rapid and effective formation of carbon-based composite electrode materials suitable for LICs anode and cathode is still a key problem. Herein, an effective approach for fabricating a three-dimensional (3D) graphene nanoscroll-wrapped carbon nanotube (CNT/rGOR) material through a facile spray-freezing process followed by a self-propagating reaction has been presented. The unique 3D conductive network structure enhances the conductivity of the electrode material, facilitating efficient charge transport and ion diffusion. The distinctive characteristics of CNT/rGOR materials allow their application as both anode and cathode electrodes in LICs. As an anode, CNT/rGOR exhibits a high specific capacity of 1483.3 mAh g-1 and excellent rate performance. And it demonstrates a high capacity of 120.0 mAh g-1 with a capacity retention of 99.0% after 9000 cycles being as a cathode. The constructed devices showcase an energy density of 213.1 Wh kg-1 at 452 W kg-1 and 102.2 Wh kg-1 at an ultrahigh power density of 45.2 kW kg-1, along with long cycling life, retaining 87.1% capacity after 6000 cycles. The structure design of these electrodes provides a strategy for addressing the mismatch in LIC electrodes and constructing high-performance symmetrical LICs.