▎ 摘　　要

In this work, the Li-ion batteries (LIB) made with 3D network structure anodes were fabricated through incorporating ultrathin delta-MnO2 nanoparticles (NPs) into a reduced graphene oxide aerogel (RGOA), while KMnO4 was employed as a raw for preparing delta-MnO2. The influence of MnO2 adding amounts on the electrochemical performance of the obtained RGOA/delta-MnO2 composite electrode was investigated. As the MnO2 adding amount increased, the electrochemical performance of RGOA/delta-MnO2 was increased firstly and then decreased, reaching a maximum reversible capacity of 1 701.9 mA.g(-1) at a suitable loading amount of MnO2, which is significantly higher than the theoretical capacity of delta-MnO2 (1 230 mAh.g(-1)). Besides, for the LIBs containing RGOA/delta-MnO2 anodes, a high capacity of 210.5 mA.g(-1) remained even after 600 discharge-charge cycles at 5 A.g(-1). The excellent performance of RGOA/delta-MnO2. 160 mg can be attributed to the synergistic effect from large specific area and high conductivity of RGOA, as well as high theoretical capacity and small particle size of delta-MnO2. Furthermore, the 3D framework porous structure provided by RGOA makes it possible to wrap delta-MnO2 NPs, avoiding the volume expansion of delta-MnO2 and suppressing the thickening of solid electrolyte interphase (SEI) layer. By calculating the contributions from pseudocapacitance and diffusion-controlled process, it was demonstrated that the charge/discharge mechanism of the RGOA/delta-MnO2-160 mg anode was dominated by the pseudocapacitance process, which also facilitated achieving good rate performance and cyclic stability.