Carbon-Coated MnO Quantum Dot-Decorated Three-Dimensional Graphene Aerogel Composite for High-Performance Lithium-Ion Batteries

Abstract

Herein, carbon-coated MnO QDs decorated on a graphene aerogel (GA, C@MnO QDs/GA) were fabricated by forming a manganese oxide gel in situ on the GA, followed by supercritical drying and carbonization. The composite combines the uniform distribution of ultra-small MnO QDs and the conducting GA with the 3D porous interconnected network structure. The well-dispersed tiny MnO quantum dots can buffer the volume change and shorten the ion diffusion path to improve the reaction kinetics. The GA can provide a 3D conductive channel for rapid electron transfer and Li+ diffusion. When used as anodes for Li-ion batteries, C@MnO QDs/GA electrodes displayed superior electrochemical performance, such as ultra-high discharge capacity, excellent cycling stability, and outstanding rate performance. A high discharge capacity of 1698 mA h g–1 was delivered after 100 cycles at 200 mA g–1, and a capacity of 702 mA h g–1 can be retained at a high current density of 2000 mA g–1. The results suggest that the C@MnO QDs/GA materials designed in this work can be potential anodes for high-performance LIBs, providing meaningful implications for further exploration of oxide anodes for next-generation alkali metal-ion batteries.