Pseudocapacitive Lithium Storage in Three-Dimensional Cobalt-Doped MnO/Nitrogen-Doped Reduced Graphene Oxide Aerogels as High-Rate Anode Material

摘要

Structural design and modification are effective measures to improve the lithium storage performance of electrode materials. Herein, three-dimensional (3D) porous Co-doped MnO/nitrogen-doped reduced graphene oxide aerogels (Co-MnO/NG-G) have been prepared by successive self-assembly processes, including the self-assembly nucleation of Co-MnO on GO in H2O/N,N-Dimethylformamide (DMF) mixed solvent, and the 3D reduction-assembly of hydrogels accompanied with nucleation-inducing growth of Co-MnO nanocrystals. Due to high-efficient electron/ion transport channels dating from the novel 3D porous microstructure and improved electron/ion conductivity deriving from doping MnO with Co, the 3D Co-MnO/NG-G electrode demonstrates high pseudocapacitive lithium storage behavior with 88.3 % at 2 mV s(-1). As an anode in lithium-ion battery, the 3D Co-MnO/NG-G shows a high capacity of 982.8 mAh g(-1) at 0.5 A g(-1) after 100 cycles, outstanding rate capability with 424.0 mAh g(-1) at 8 A g(-1), as well as superior cycle stability with 508.9 mAh g(-1) after 800 cycles at 4 A g(-1). This work demonstrates that the synergistic strategy between cation doping and 3D porous channels for electron/ion transport is an effective way to design high-rate anode materials.