A bi-functional metal-free catalyst composed of dual-doped graphene and mesoporous carbon for rechargeable lithium–oxygen batteries

Abstract

Mesoporous carbon on nitrogen and sulfur co-doped graphene nanosheets (NSGC) was synthesized and its bi-functional catalytic activity toward oxygen reduction reaction and oxygen evolution reaction was investigated. The NSGC material showed high bi-functional catalytic activity due to the synergistic effect of co-doping of sulfur and nitrogen, as well as the presence of a hierarchical porous structure. The enhanced bi-functional catalytic activity of NSGC facilitated the efficient formation and decomposition of Li 2 O 2 on the air cathode. The lithium-oxygen cell assembled with the NSGC-based air cathode delivered a high initial discharge capacity of 11 431 mA h g À1 and exhibited good cycling stability. The hybrid structure consisting of mesoporous carbon with co-doped graphene nanosheets can be an effective strategy to improve the round-trip efficiency and cycle life of lithium-oxygen batteries.

Carbon‐Based Metal‐Free Catalysts for Electrocatalysis beyond the ORR

“…With the aid of LiI as a redox mediator, Liu et al have recently demonstrated a high capacity (typically between 25 000 to 40 000 mAh g À1 ), comparable to the theoretical value of Li-O 2 batteries, for a RGO framework electrode. [113] In this case, the mesoporous structure can accommodate the insoluble Li 2 O 2 formed during discharge. [113] In this case, the mesoporous structure can accommodate the insoluble Li 2 O 2 formed during discharge.…”

Recent Advances in Heteroatom-Doped Graphene Materials as Efficient Electrocatalysts towards the Oxygen Reduction Reaction

“…65 They found that the N and S dual-doped graphene has better catalytic activity on ORR than only N-doped graphene, probably due to the synergistic effect of dual-doping and superiority of S than N with two lone-paired electrons. The improved electrocatalytic activity caused by N and S atoms paves the way of practical application of NSG in the Li-air batteries, as demonstrated by Kim et al 66 The electrochemical performance of NSG reported in recent years is summarized in Table 2.…”

Kohlenstoffbasierte Metallfreie Katalysatoren für die Elektrokatalyse jenseits der ORR

“…[110] Als Kathode in einem Li-O 2 -System zeigte dieses Material eine gute Entladungsrate mit einer spezifischen Entladungskapazität von 1280 mAh g À1 selbst bei einer hohen Stromdichte von 200 mA g À1 . [113]. Copyright 2011 American Chemical Society).…”

“…c) Hochauflçsende TEM-Aufnahme von NSGC, die die mesoporçse Morphologie auf der rGO-Oberfläche zeigt. [113] [113].…”

“…[112] Hybride aus mesoporçsem Kohlenstoff auf mit N und S kodotierten Graphen-Nanoblättern (NSGC) besitzen eine große aktive Oberfläche sowie eine hohe Elektronen-/Elektrolytleitfähigkeit und wurden ebenfalls als Luftkathoden verwendet (Abbildung 11 c). [113]…”