Graphene-templated growth of vertical MnO nanosheets with open macroporous architectures as anode materials for fast lithium storage

摘要

Transition metal oxides (TMOs) have emerged as one of the promising and intriguing materials for next-generation lithium-ion battery (LIB) anodes with high capacities. However, the poor power capability and inferior cyclic stability of TMO anodes, caused by the low electrical conductivity and large volume changes, cannot meet the rapidly growing demands of commercial applications. Developing TMO-anode materials with high-performance has become an important research focus. In this study, vertical MnO nanosheets using graphene as a template (M-GS) with 3D open macroporous architectures are prepared by a low-temperature hydrothermal method combined with a heat treatment. As anodes for LIBs, M-GS electrodes display the high reversible capacity (819.8 mAh g(-1) at the current density of 250 mA g(-1)) and long cyclic performance (606.2 mAh g(-1) with 127% capacity retention after 200 cycles at 1500 mA g(-1)). Furthermore, obvious rising reversible capacities are acquired with the increasing C-rates, and the maximum capacity is at 2500 mA g(-1), implying the outstanding rate capability. These excellent properties benefit from the coexistence of vertical MnO nanosheets and graphene and their synergetic effects. The tight attaching of MnO nanosheets on graphene remarkably improves the electrical conductivity and structural stability for impressive cyclability, and the open macroporous architectures alleviate the volume changes and shorten diffusion paths of ionic/electronic transport for fast lithium storage. (C) 2018 Elsevier B.V. All rights reserved.