Direct Growth of Flower‐Like δ‐MnO₂ on Three‐Dimensional Graphene for High‐Performance Rechargeable Li‐O₂ Batteries

Abstract

A challenge still remains to develop high‐performance and cost‐effective air electrode for Li‐O2 batteries with high capacity, enhanced rate capability and long cycle life (100 times or above) despite recent advances in this field. In this work, a new design of binder‐free air electrode composed of three‐dimensional (3D) graphene (G) and flower‐like δ‐MnO2 (3D‐G‐MnO2) has been proposed. In this design, graphene and δ‐MnO2 grow directly on the skeleton of Ni foam that inherits the interconnected 3D scaffold of Ni foam. Li‐O2 batteries with 3D‐G‐MnO2 electrode can yield a high discharge capacity of 3660 mAh g−1 at 0.083 mA cm−2. The battery can sustain 132 cycles at a capacity of 492 mAh g−1 (1000 mAh gcarbon −1) with low overpotentials under a high current density of 0.333 mA cm−2. A high average energy density of 1350 Wh Kg−1 is maintained over 110 cycles at this high current density. The excellent catalytic activity of 3D‐G‐MnO2 makes it an attractive air electrode for high‐performance Li‐O2 batteries.

A combined approach for high-performance Li–O2 batteries: A binder-free carbon electrode and atomic layer deposition of RuO2 as an inhibitor–promoter

“…S2 of the supplementary material, three new peaks were observed in the Raman spectra of the RuO 2 /CNT electrodes that are associated with the Raman active modes of RuO 2 : ∼494 cm 1 for E g , ∼613 cm 1 for A 1g , and ∼685 cm 1 for B 2g . 21,38 These results in Fig. 2 provide clear experimental evidence confirming that RuO 2 was formed on CNTs during the ALD process.…”

Hierarchical Structures Based on Two‐Dimensional Nanomaterials for Rechargeable Lithium Batteries

“…[35] From the point of energy storage devices, the resulting 3D macro-structures (e.g., graphene foams (GFs), [36][37][38][39][40][41] graphene aerogels(GAs), graphene sponges(GSs) [63][64][65] and etc. This type of hierarchical structure have been extensively applied in popular 2D nanomaterials.…”

“…To enhance the cathodic reaction kinetics for low charge overpotentials and high energy efficiency, it has been a prevalent approach to develop composite cathodes by loading catalysts, such as noble metal, [69] metal oxide [41,65,66,183] and others. To enhance the cathodic reaction kinetics for low charge overpotentials and high energy efficiency, it has been a prevalent approach to develop composite cathodes by loading catalysts, such as noble metal, [69] metal oxide [41,65,66,183] and others.…”

Restoration of thermally reduced graphene oxide by atomic-level selenium doping

“…Additionally, when a soluble LiI catalyst was used, the Se-rGObased electrode showed an abrupt decrease of charge polarization near 0.5 V (Figure 5e), which was superior to the previous reports on rGO electrodes in terms of energy efficiency. [55][56][57] These results, thus, demonstrate the possibility of using Se-rGO-based electrodes for Li-O 2 batteries.…”