Anchoring Nitrogen-Doped TiO_2 Nanocrystals on Nitrogen-Doped 3D Graphene Frameworks for Enhanced Lithium Storage

摘要

An advanced architecture design of nitrogendoped TiO_2 anchored on nitrogen-doped 3D graphene framework composites (denoted as N-TiO_2/N-3D GFs) have been fabricated by a facile template process and further NH3 treatment. The 3D graphene framework allows the electrolyte to penetrate into the inverse opal structure, and possesses high electronic conductivity. The close contact between the N-TiO_2 and the graphene suppresses the growth and aggregation of TiO_2 nanoparticles during heating process, leading to decreased Li~+ diffusion length. The N-doping in both TiO_2 and the graphene matrix could improve the electronic conductivity on the TiO_2 particle surface and between adjacent particles. As expected, when used as an anode for Li-ion batteries (LIBs), the NTiO_2/ N-3D GFs composite delivers an excellent reversible capacity of 165 mAhg~(-1) after 200 cycles at 100 mAg~(-1) and an outstanding rate capability of 114 mAhg~(-1) after 1000 cycles at 1 Ag~(-1). With rational design, this strategy could be extended to other electrode materials that may hold great promise for the development of high energy storage systems.