N-Doped Mesoporous Carbon Film with Pinned Carbon Nanotube as Free-Standing Anode for Fast-Charging Li-Ion Batteries

A N-doped mesoporous carbon film with a pinned carbon nanotube was prepared by a hydrothermal soft-template self-assembly and metal-catalyzed graphitization approach, using phenolic resin/dicyandiamide as the solid carbon and nitrogen sources and F127 micelles as a mesoporous template. The thickness of the mesoporous carbon membrane was determined by the polymerization degree of phenolic resin and was adjustable by tuning the reagent concentration in the hydrothermal reaction. These NMCF-NCNT films show a high graphitization degree, large specific surface area, rich nitrogen dopant, and high mechanical strength. Importantly, the NCNT grown on the mesoporous carbon film constructs a conductive pathway between the carbon film and coin cell, and the mesopores in NMCF accelerate the electrolyte diffusion when NMCF-NCNT films are applied as free-standing anodes in LiBs. The NMCF-NCNT-1 with a thickness of 1 μm delivered the optimum electrochemical properties of 750 mAh g-1 at 0.1 A g-1, 578 mAh g-1 at 5 A g-1 after 30 cycles, and 661 mAh g-1 at 1 A g-1 after 600 cycles. Such good electrochemical performance could be attributed to the thinnest NMCF-NCNT-1 membrane granting high electrical conductivity, fast Li+ diffusion, and preeminent structural stabilization. This work aims at the preparation of a self-supporting-structured mesoporous carbon film with pinned carbon nanotube, the regulation of micro-nanostructure, and the optimization of electrochemical performance, which may gain a new insight into the design of free-standing carbon membrane electrodes for fast-charging LiBs.