MnO@N-C/flake graphite composite featuring bottom-top charge transfer channels and superior Li-storage performance at low-temperature

摘要

The common nanocomposites that containing high specific capacity anode materials often suffer from particle aggregation, severe side reactions, and huge irreversible Li-storage due to their high specific surface area exposed to electrolyte. To tackle these issues, an engineered structure with robust framework and moderate surface area is rationally designed in this work through a post-construction strategy. In the target sample, the MnO nanoparticles coated by N-doped carbon layer (N-C) are in situ formed and stacked on the micro-scale conductive flake graphite (FG), forming a plum-pudding like structure (MnO@N-C/FG). Of particular note is that the thin N-C layer together with FG could significantly enhance the electroconductivity of the whole electrode and confine the aggregation of MnO nanoparticles upon cycling. Moreover, the robust FG skeleton can endow the MnO@N-C with superior structural stability during deep charge-discharge processes. As a result, due to the synergetic effects of its unique plum-pudding like structure, the MnO@N-C/FG exhibits superior electrochemical performances at a wide temperature range. For example, a decent reversible capacity of 382.4 mAh g(-1) can be obtained even operated at -20 degrees C, indicating its potential use at a stern temperature, which makes MnO@N-C/FG composite a practical anode material for Li-ion batteries. (C) 2020 Elsevier B.V. All rights reserved.