Bottom-Up Construction of Reduced-Graphene-Oxide-Anchored MnO with an Nitrogen-Doped Carbon Coating for Synergistically Improving Lithium-Ion Storage

Inorg Chem. 2018 Nov 5;57(21):13693-13701. doi: 10.1021/acs.inorgchem.8b02270. Epub 2018 Oct 17.

Abstract

Designing an advanced architecture to overcome the innate issue of MnO-based anode materials in terms of low electrical conductivity and severe volume change during cycling is still a challenge toward which more effort needs devoted. Here, an intriguing hybrid involving the architecture of reduced graphene oxide (RGO)-anchored MnO within an nitrogen-codoped carbon coating (RGO-MnO@NC) is reported via a simple and facile approach and regarded as a promising lithium-ion (Li+) anode material with high rate capacity, large specific capacity, and a long cycle lifespan simultaneously. The resulting porous conductive carbon layer could not only promote the electron/ion transfer but also alleviate the volume variation for retaining a relatively stable solid electrolyte interphase and prevent MnO from direct contact with the electrolyte to reduce unexpected lithium consumption. The existing internal voids offer the space to accommodate volume expansion in the lithiation/delithiation processes, and RGO could build a large conductive network for better electron transfer. Consequently, the RGO-MnO@NC electrode presents high Li+ storage capacity (699 mAh g-1 at 0.1 A g-1), excellent cycling performance (607 mAh g-1 at 1 A g-1 over 550 cycles), and a remarkable rate performance. Through kinetic analysis, it is revealed that RGO-MnO@NC exhibits an enhanced capacitive contribution for Li+ storage, showing a typical faradaic surface pseudocapacitive mechanism. This work proposes a new strategy to ameliorate the deficiency of the electrode material toward the conductivity and volume change for enhanced Li+ storage.