▎ 摘　　要

In this study, we have fabricated carbon dot/ reduced graphene oxide (CDs/rGO) composites using oxygenfunctionalized CDs and conductive graphene oxide (GO) by a hydrothermal method and calcination at 250 degrees C. The CDs can manipulate the surface functional groups of the composites by consuming C-O bonds and introducing C=O bonds. As sodium ion battery anodes, CDs/rGO with a high C=O group content exhibits a great reversible capacity of 308 mAh g-1 at 0.05 A g-1, which is up to 1.8 times that of rGO (173 mAh g-1). It retains a capacity of 116 mAh g-1 after 2000 cycles at 2 A g-1. When assembled into a full cell, the activated anode and NVP@C display a higher initial discharge capacity of 291 mAh ganode-1 with an average working voltage of 2.5 V. The good performance of CDs/ rGO is mainly due to the synergistic effects of the CDs with abundant Na storage sites and rGO with a conductive network. The improved electrochemical properties are dominated by the capacitive Na storage mechanism. This work implies that the oxygenfunctionalized CDs could serve as medium to regulate the surface chemistry of carbon materials.